tag:theconversation.com,2011:/us/topics/sick-80067/articlesSick – The Conversation2023-11-06T13:33:20Ztag:theconversation.com,2011:article/2129492023-11-06T13:33:20Z2023-11-06T13:33:20ZWhy do our noses get snotty when we are sick? A school nurse explains the powers of mucus<figure><img src="https://images.theconversation.com/files/548367/original/file-20230914-21-s25lth.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C1196%2C797&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Use a tissue and wash your hands after a booger explosion.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/schwachs/4352350750/">Joshua Wachs/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<p><strong>Why do our noses get snotty when we are sick? – Veronica P., age 5, Panama City, Florida</strong></p>
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<p>Not many things are as uncomfortable and annoying as a runny or congested nose when you’re sick. Constantly blowing your nose and not being able to breathe through it may leave you wondering: Why does this happen? </p>
<p>I’m a nurse practitioner who works with kids every day and also <a href="https://stories.purdue.edu/kristin-ahrens/">teaches nursing</a>. The answer is pretty simple. Mucus – or snot – is one of the ways your body helps keep you healthy. </p>
<p>Mucus lines your nose, throat, lungs and other parts of your body to protect it from bad bacteria, viruses and other particles. Your body <a href="https://www.everydayhealth.com/mucus/">continuously creates mucus</a> to fight off germs and help get rid of them. </p>
<p>When you’re sick, your immune system ramps up to produce extra mucus to flush out germs. While it might seem gross, mucus is also pretty amazing.</p>
<h2>Slimy protector</h2>
<p>Your body creates mucus out of a combination of <a href="https://www.britannica.com/science/mucus">water, proteins and salts</a>. Its sticky consistency traps bad microorganisms and other unwanted particles, like dust, pet dander and mildew, so they can’t get farther into your system. </p>
<p>Some components in mucus <a href="https://www.nibib.nih.gov/news-events/newsroom/disarming-bacteria-mucus-and-phages">stop bacteria from banding together</a> and becoming more dangerous. Other elements can actually <a href="https://doi.org/10.1007/BF02976990">kill the invaders</a> that are trying to make you sick. And though scientists don’t completely understand how, the <a href="https://doi.org/10.1007/BF02976990">proteins and genes in mucus</a> seem to work together to make it thicker and stickier if necessary.</p>
<p>Once germs or other potentially damaging particles are trapped and neutralized, your body’s way of getting rid of them altogether is to make so much mucus that you have to blow, sneeze or cough them out. </p>
<p>You might have noticed that sometimes when you’re sick, your nose can get red too. This is because your immune system, in addition to making mucus, also sends extra white blood cells to the source of an infection. As they rush to the scene to help fight infection, the extra white blood cells <a href="https://my.clevelandclinic.org/health/articles/21196-immune-system/">expand the blood vessels</a> in the area, making your nose look red. All the wiping and blowing can make it red, too.</p>
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<a href="https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart displaying mucus colors from clear to black and describing what each means." src="https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=960&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=960&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=960&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1206&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1206&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548373/original/file-20230914-9125-jab4s8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1206&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The mucus rainbow.</span>
<span class="attribution"><a class="source" href="https://riseandshine.childrensnational.org/snot-colors-and-what-they-mean/">Children's National Hospital</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
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<p>Snot can come in a rainbow of yucky colors. When white blood cells are fighting an infection, they release chemicals that may <a href="https://www.healthline.com/health/snot-color#white-snot">turn your snot yellow</a>. When more of those cells are needed to get the job done, mucus can even turn green. Typically, after a few days, colored mucus changes back to clear and your stuffy nose will go away. </p>
<h2>Not just in your nose</h2>
<p>Mucus isn’t found just in your nose and lungs.</p>
<p>Your <a href="https://theconversation.com/can-you-cry-underwater-205464">eyes also have a thin layer of mucus</a> that helps protect them from particles in the air. When you get sick or get an eye infection, <a href="https://www.verywellhealth.com/eye-mucus-types-3422108">eye mucus</a> can act the same way it does in your nose – catching and killing germs. Eye mucus can also sometimes turn thick and yellow. If that happens, you’ll want to call your health care provider. Don’t ever touch your eyes with your fingers. That can <a href="https://www.nyoph.com/blog/this-is-why-you-shouldnt-rub-your-eyes/">introduce more germs</a>.</p>
<p>Your stomach and intestines also have protective mucus. If you’ve ever had an upset stomach that led to diarrhea, the mucus in your intestinal track was working overtime to help <a href="https://doi.org/10.1038/nrgastro.2013.35">flush out bad bacteria</a>. That’s why your normal poop goes from a solid mush to something more slimy. There are other reasons you can have stomachaches – like stress, constipation or food allergies – but if you have diarrhea, your mucus is definitely hard at work. </p>
<h2>Animals have it too</h2>
<p>Humans aren’t the only animals that use mucus. For example, <a href="https://petriage.com/clinical-insights/your-pets-mucous-membranes/">dogs and cats have mucus</a> too.</p>
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<a href="https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A brightly colored fish is surrounded by a mucus cocoon on the sea floor next to some rocks. A smaller fish is nearby." src="https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548831/original/file-20230918-31-zzsqlo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Some fish use mucus for protection while sleeping.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Abrolhos_Marine_National_ParkRobertoCostaPinto20.jpg">RobertoCostaPinto/WikiMedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p><a href="https://www.montereybayaquarium.org/stories/mucus-slime-snot">Parrotfish</a>, <a href="https://doi.org/10.1098/rsbl.2010.0916">wrasses</a> and <a href="https://cimi.org/blog/mucus-in-the-animal-kingdom/">other sea creatures</a> produce mucus cocoons to help protect them from predators at night. </p>
<p>Chameleons use the sticky <a href="https://www.nationalgeographic.com/animals/article/chameleon-tongue-mucus-sticky-animals">mucus on the end of their tongues</a> to reel in their prey. Earthworms secrete mucus to help them move through the soil, which in turn <a href="https://doi.org/10.5194/egusphere-egu2020-17611">benefits the soil</a>.</p>
<p>In humans, mucus helps neutralize and eliminate the microbial bad guys. So the next time you reach for a tissue to blow your nose, remember: Your body’s natural defenses are doing their best to keep you healthy or make you better. Just think of all that snot as one of your body’s superpowers.</p>
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<p class="fine-print"><em><span>Kristin Ahrens is a member of the National Association of Pediatric Nurse Practitioners (NAPNAP) and the National Association of School Nurses (NASN). </span></em></p>Slimy snot is an important part of how your immune system wards off germs and fights back from infection.Kristin Ahrens, Pediatric Nurse Practitioner, Adjunct Instructor of Nursing at Purdue Global, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081562023-06-23T13:39:47Z2023-06-23T13:39:47ZDirty tea towels are breeding grounds for harmful bacteria – here’s how to clean them properly<figure><img src="https://images.theconversation.com/files/533147/original/file-20230621-15-81vklh.jpg?ixlib=rb-1.1.0&rect=123%2C0%2C6227%2C4218&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Yep, when you've finished, both of those need to go in the wash.</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/close-up-of-women-in-pattern-dresses-drying-cutlery-with-tea-towels-6956744/">pexels/karolina grabowska</a></span></figcaption></figure><p><a href="https://link.springer.com/article/10.1023/A:1016378226861">Kitchens</a> can harbour all sorts of germs and bacteria. These can arrive via humans, pets, uncooked food or even plants, meaning that a high proportion of <a href="https://academic.oup.com/jambio/article-abstract/119/2/582/6717307?redirectedFrom=fulltext">foodborne infections</a> are acquired directly within the home. </p>
<p>An important cleaning aid in most kitchens is the tea towel, also known as a dishcloth. Usually made of cotton or linen, they are used to dry wet hands and kitchen implements as well as wiping down surfaces – so play an important role in kitchen hygiene. </p>
<p>But, because hands and uncooked fresh produce are often rich in a diverse variety of germs, tea towels are prone to picking up the bacteria they come into contact with. </p>
<p>Indeed, in a <a href="https://www.semanticscholar.org/paper/Achieving-hygiene-in-the-domestic-kitchen%3A-the-of-Cogan-Slader/ffc798f7219afc6f986d6f18c62e6e496e7e0161">study</a> that used tea towels to wipe down chopping boards that had been used to prepare raw chicken with salmonella (which can cause diarrhoea, fever and stomach cramps), 90% of the cloths became contaminated with salmonella, too.</p>
<p><a href="https://www.tandfonline.com/doi/abs/10.1080/09603129509356839?src=recsys">Several studies</a> have looked at the germs tea towels typically carry in domestic kitchens. One study sampled 100 used tea towels and found a marked presence of <a href="https://www.tandfonline.com/doi/abs/10.1080/09603120050127202?src=recsys">staphylococcus aureus</a> <em>Staphylococcus aureus</em>, which is often found on the skin but is also a pathogen that can cause a variety of issues such as abscesses, joint infections and even pneumonia.</p>
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<img alt="Tea towels hanging to dry on the oven door." src="https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Dirty tea towels are a breeding ground for bacteria and foodborne illnesses.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-teatowels-on-rack-2293555605"> Joe Kuis/Shutterstock</a></span>
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<p>Tea towels are good at picking up germs which is important as another <a href="https://www.tandfonline.com/doi/abs/10.1080/09603129509356839?src=recsys">study of 46 kitchens</a> found a wide range of harmful bacterial species living on kitchen surfaces, which are often cleaned by tea towels. </p>
<p>Surfaces were found to have <em>Enterobacter</em> (which can cause respiratory tract infections, skin infections, urinary tract infections and heart, bone and eye infections), <em>Klebsiella</em> (which has been linked to serious infections of the lungs, bladder, brain and blood), and <em>E. coli</em> (which can cause upset stomachs and urinary tract infections). </p>
<p>Several kitchens also had <em>Pseudomonas aeruginosa</em>, which can cause lung infections. <em>Bacillus subtilis</em>, which can lead to eye infections and abscesses, was also found in more than half of the kitchens sampled. And all of the samples from the kitchens were found to have <em>Staphylococcus</em> and <em>Micrococcus</em>. In people with weak immune systems, <em>Micrococcus</em> has been linked to lung infections, such as pneumonia and septic arthritis along with eye and heart infections.</p>
<p>The levels and types of germs found on these tea towels were influenced by how they were used, how often they were washed and how long they were dried for. <a href="https://www.sciencedirect.com/science/article/pii/S0956713522003887?via%3Dihub">Rinsing tea towels in hot water</a> at 60°C was found to reduce levels of bacteria later spread by contaminated cloths, which is important as infection likelihood is often related to how many bacteria you ingest.</p>
<h2>Clean your cloths</h2>
<p>These studies suggest there is an infection risk from tea towels and that most kitchen cloths may be contaminated with high levels of bacteria. It’s easy, then, for these germs to transfer on to food preparation surfaces, potentially causing serious food poisoning. </p>
<p>The infection risk of using tea towels is well-recognised by the medical profession. Indeed, in UK hospitals, fabric <a href="https://www.leicspart.nhs.uk/wp-content/uploads/2021/02/Food-Hygiene-for-Ward-and-Therapy-kitchens-Infection-Prevention-Policy-exp-Feb-24.pdf">tea towels are not allowed</a>. Instead, patient crockery, cutlery and food preparation work surfaces are cleaned and dried with disposable paper towels. </p>
<p>One of the reasons tea towels act as such good microbial reservoirs is that they are often damp as they are used to absorb moisture and mop up spills. <a href="https://www.sciencedirect.com/science/article/pii/S0956713522003887?via%3Dihub">Water enables germs to grow</a>. And so a moist tea towel left in a warm kitchen provides an ideal environment for bacteria to multiply. This is particularly the case if food traces are present, too. </p>
<p>So what’s the best way to sanitise your used tea towel? Tea towels that are hung up in the air tend to dry faster than cloths stored and squeezed into balls, which can affect levels of bacteria in the towels. </p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0956713522003887?via%3Dihub">Laboratory experiments</a> that involved covering tea towels in salmonella, found that the bacteria multiplied in all types of cloths that were crumpled. But levels of bacteria were reduced by 1,000 times if the tea towels were hung to dry for 24 hours at room temperature. </p>
<h2>Reduce the germs</h2>
<p>To avoid tea towels spreading germs around the kitchen, it’s recommended that the cloths are washed regularly and when they get wet, are allowed to dry completely before being used again. Using <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">disposable cloths</a> or paper towels for heavily contaminated areas, such as those involving raw meat, could also help to stop the spread of bacteria. </p>
<p>In terms of tea towel hygiene, you should clean and thoroughly dry your kitchen towel <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">at least once a day</a> or after each use. The UK government recommends that tea towels should be sanitised by washing them in a washing machine with laundry detergent on a hot wash cycle of 90°C. </p>
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<img alt="Tea towels drying on a clothesline." src="https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Daily washing of tea towels is crucial for kitchen hygiene.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/colourful-towels-tea-hung-outside-dry-1655802655"> Tony Skerl/Shutterstock</a></span>
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<p>Laundry detergents contain hard water softeners, surfactants (which increase the wetting effect of water by reducing its surface tension), detergents, bleaches and digestive enzymes. Food stains on tea towels will probably be a mixture of proteins, fats and carbohydrates, which the enzymes degrade. </p>
<p>And the detergent helps to dissolve the stains, which are released into the washing water. Since proteins and fats are also involved in the attachment of bacteria to surfaces, laundry detergents will help to detach and so reduce bacteria levels in tea towels. </p>
<p>If you <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">wash tea towels</a> by hand, ensure any obvious food and dirt are removed by rinsing in hot water with detergent before disinfection. After washing, you can sanitise any microbes remaining using boiling water or a disinfectant such as bleach, diluted as per the manufacturer’s instructions. </p>
<p>Ironing tea towels on a hot setting will also effectively sanitise as the temperature is <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">above 90°C</a>.
You should also store your laundered tea towels in a dry, clean area, away from any uncooked food and grubby hands.</p><img src="https://counter.theconversation.com/content/208156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Primrose Freestone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A microbiologist on the deadly germs lurking in your kitchen and why you need to wash tea towels and dishcloths more often.Primrose Freestone, Senior Lecturer in Clinical Microbiology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1828232022-05-24T13:52:25Z2022-05-24T13:52:25ZHere’s why you might feel sick after a workout – and what you can do to prevent it<figure><img src="https://images.theconversation.com/files/465052/original/file-20220524-14-fl482a.jpg?ixlib=rb-1.1.0&rect=51%2C0%2C5740%2C3823&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Feeling sick after a workout is usually no cause for alarm.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/male-asian-athlete-having-abdominal-pain-2039907389">voronaman/ Shutterstock</a></span></figcaption></figure><p>Many of us exercise to feel better. While some of us get “runners’ highs” after a workout, unfortunately some of us leave the gym feeling nauseous. Though this is usually only temporary, it can still be uncomfortable. Fortunately there are a few good explanations for why this may be happening – so if this happens to you there’s probably no reason to be alarmed.</p>
<p>When we exercise, there’s an increase in blood flow to the working muscles, brain, lungs and heart. This increase in blood flow is driven by the sympathetic part of the autonomic nervous system (which helps regulates all of our involuntary body responses, such as heart rate, blood pressure and digestion). It does this by <a href="https://www.frontiersin.org/articles/10.3389/fphys.2012.00284/full">widening the arteries</a> so they can carry more blood to these tissues. </p>
<p>But the sympathetic nervous system, which normally drives our “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4495877/">fight or flight</a>” mechanism, simultaneously <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1432887/">narrows the blood vessels</a> going into our gastrointestinal system (such as our stomach) during a strenuous workout by up to 80%. It does this because there’s a limited quantity of blood in the body, and the increased oxygen demand by some tissues can only be met by altering the amount of blood going to other tissues. This means that blood supply may be reduced in areas that don’t currently need as much oxygen at that time. This can be the case whether or not you’ve recently eaten.</p>
<p>But let’s say you’ve recently eaten a meal before heading to the gym or going for a run. When we eat, the food <a href="https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works#:%7E:text=into%20your%20esophagus.-,Stomach.,chyme%2C%20into%20your%20small%20intestine.">stretches our stomach</a>, resulting in the release of acid and enzymes needed to digest the food. The stomach muscles also <a href="https://journals.physiology.org/doi/full/10.1152/advan.00025.2003">become more active</a> during digestion, causing greater demand for oxygen and blood flow to the stomach and other gastrointestinal tissues. A different part of the autonomic nervous system causes blood flow to increase to the gastrointestinal structures when they <a href="https://www.ncbi.nlm.nih.gov/books/NBK538516">need to be active</a>.</p>
<p>The significant conflict in the body from different tissues all demanding oxygen may be one reason why nausea happens during or after a workout. The body has to adapt the blood flow to the tissues as demand changes. So, when we work out, blood needs to go to the muscles, heart, lungs and brain, meaning blood flow is reduced in less active tissues, such as the gastrointestinal tract – even if it’s currently digesting our dinner. When blood flow is reduced in this area, it triggers our intestinal nerves, which subsequently causes <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198651/">feelings of nausea</a>.</p>
<p>On top of this, the stomach and other abdominal organs can also be compressed during exercise, which may further contribute to feelings of nausea. This is particularly an issue in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6945051/">squatting</a>, as the heart rate and oxygen demand in tissues increases, so the body draws larger volumes of air into the lungs. This then causes the diaphragm (under your ribs) to push down harder on the abdominal organs. Other muscles – such as those in the abdominal wall – also help, further squeezing the abdominal organs with every breath. This can result in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/apt.14157">significant nausea and even vomiting</a> – even on an empty stomach. </p>
<figure class="align-center ">
<img alt="A group of marathon runners racing outdoors. A man and a woman are at the front of the group." src="https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465054/original/file-20220524-22-reicdp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Endurance sports may actually be bad for the stomach.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/bamberg-germany-may-03-2015-weltkulturerbelauf-276219920">Andreas Zerndl/ Shutterstock</a></span>
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<p>Some evidence even suggests that exercise, particularly long distance running and other endurance events, can damage the <a href="https://pubmed.ncbi.nlm.nih.gov/1589703/">stomach lining</a> – likely due to the <a href="https://gut.bmj.com/content/48/3/435">decrease</a> in blood flow and oxygen available to the organ. This would also cause nausea. In extreme circumstances this can result in <a href="https://journals.lww.com/co-clinicalnutrition/Abstract/2009/09000/The_impact_of_physical_exercise_on_the.13.aspx">bleeding</a> of the <a href="https://pubmed.ncbi.nlm.nih.gov/8338081/">stomach lining</a>, particularly in endurance and long distance athletes. </p>
<h2>When to eat</h2>
<p>If you exercise immediately or up to an hour after eating, you’re more likely to <a href="https://www.sciencedirect.com/science/article/abs/pii/S019566630090391X">experience nausea</a> – regardless of exercise level or workout intensity. It takes <a href="https://pubmed.ncbi.nlm.nih.gov/17074022/">approximately two hours</a> for solid food to be <a href="https://www.ncbi.nlm.nih.gov/books/NBK537005/">broken down by the stomach</a> and enter the small intestines, so if you experience nausea after workouts, it might be best to wait at least two hours after a meal. </p>
<p>What you eat before a workout may also determine whether you experience nausea. High fibre, fatty, and even high protein foods are all linked to <a href="https://link.springer.com/article/10.1007/s40279-014-0153-2">greater likelihood</a> of nausea after a workout. Supplemental protein, <a href="https://academic.oup.com/ajcn/article/102/6/1574/4555193">particularly whey or shakes</a>, are also digested more slowly. This is likely to contribute to nausea during a workout as the stomach tries to digest it.</p>
<p>Certain fats, particularly <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4424767/">saturated</a>, may induce nausea differently – with animal models showing they <a href="https://pubmed.ncbi.nlm.nih.gov/27873093/">irritate</a> and <a href="https://www.ahajournals.org/doi/10.1161/01.ATV.21.6.991">damage</a> the lining of the gastrointestinal tract, which activates nerves in the lining of the stomach that link to the vomiting centre (located in the medulla oblongata) in the brain.</p>
<p>Consuming sports drinks or other <a href="https://pubmed.ncbi.nlm.nih.gov/28646834/">high-carbohydrate drinks</a> (such as juices, energy drinks and sodas), are also <a href="https://link.springer.com/article/10.1007/s40279-014-0153-2">linked to nausea</a> during and <a href="https://journals.sagepub.com/doi/10.1177/0897190002239633">after a workout</a>. This may be because these drinks <a href="https://journals.sagepub.com/doi/10.1177/0897190002239633">are digested very slowly</a> and stay in the stomach longer than other drinks might.</p>
<p>If you’re someone who often experiences nausea after a workout, there are a couple of things you can do. First, change or reduce your usual workout, and build up intensity slowly. This is because the longer the workout, the more blood is consistently drawn away from the stomach. Make sure you drink enough water before and after a workout, as both too little and too much can cause nausea for different reasons. </p>
<p>In terms of eating, avoid it two hours before, and choose the right food – such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5794245/">high quality carbohydrates</a> (such as bananas or sweet potatoes) and protein, as well as unsaturated fats (such as nuts). These will not only fuel the body, but they won’t be as difficult to digest as other foods if you plan to work out.</p><img src="https://counter.theconversation.com/content/182823/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor is affiliated with the Anatomical Society. </span></em></p>Try to avoid eating an hour or two before a workout.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1798032022-04-21T09:52:27Z2022-04-21T09:52:27ZExercising while sick won’t help you get over a cold faster – but it may prevent your next one<figure><img src="https://images.theconversation.com/files/501918/original/file-20221219-14-rahmat.jpg?ixlib=rb-1.1.0&rect=28%2C42%2C9461%2C6274&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The stress of exercising while sick could potentially make our immune cells less effective.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/african-american-woman-afro-hair-holding-2140316225">Krakenimages.com/ Shutterstock</a></span></figcaption></figure><p>Exercising regularly is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7149380/">good for your immune system</a> – with some research suggesting that it may even lower the risk of getting <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7172238/">upper respiratory infections</a>, such as the common cold. Even as little as 30 minutes of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7149380/">moderate exercise five times a week</a> is enough to bring about benefits. </p>
<p>Since exercising is good for our immune system, some people might think that exercising while you’re sick can help you “sweat it out.” Unfortunately, when it comes to the common cold, there’s no evidence exercising while sick can shorten the illness or make it less severe.</p>
<p>There are a couple of reasons why exercise is beneficial for our immune system. The first may be partly explained by the hormones that are released when we exercise. These are called catecholamines – which people may better know as adrenaline and noradrenaline. These hormones play an important role in the functioning of our immune system by eliciting the quick release of important immune cells that help detect the presence of viruses or other pathogens in the body. They also increase the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7172238/">amount of movement</a> of our immune cells between the blood and tissue – which is important in helping immune cells detect and prevent illnesses caused by viruses or other pathogens. Research shows that exercise is one way we can increase the <a href="https://pubmed.ncbi.nlm.nih.gov/16959907">levels of these important hormones</a> in our body.</p>
<p>When we exercise, it also increases blood flow in order to help our body keep up with the increased demands of exercise. This elevated blood flow places greater <a href="https://pubmed.ncbi.nlm.nih.gov/1618188/">stress</a> on our blood vessels, which releases specific immune cells called <a href="https://www.sciencedirect.com/science/article/pii/S0889159109000610">natural killer cells and T cells</a> that can be found dormant on the walls of our blood vessels. Natural killer cells and T cells both play an important role in killing cells infected with a virus.</p>
<p>Exercise may also benefit our fight against infection in other ways. For example, older adults who regularly exercise over a period of one month <a href="https://academic.oup.com/biomedgerontology/article/60/11/1432/623101?login=true">have been shown to</a> to have quicker skin wound healing compared to a non-exercise control group. This quicker healing process lowers the risk of virus and bacteria entry into the body via skin wounds. </p>
<p>All of these mechanisms together <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7172238/">may improve our immune system</a> and lower the risk of getting sick from viral infections. You don’t even have to be a regular gym-goer to see benefits. <a href="https://journals.lww.com/acsm-msse/Fulltext/2000/07001/Is_infection_risk_linked_to_exercise_workload_.5.aspx">Three studies</a> have shown that when people who didn’t exercise started brisk walking regularly for 40-45 minutes, five days per week, saw 40-50% fewer days of upper respiratory tract infection symptoms when compared to a control group. </p>
<figure class="align-center ">
<img alt="Young adult man and woman go for a brisk walk in the park on a sunny day." src="https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459069/original/file-20220421-60275-wf9kgn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Exercising may reduce your likelihood of catching a cold.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/couple-brisk-walking-dusty-road-230632984">Lester Balajadia/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Despite the benefits of exercise on our immune system, it’s difficult to know whether exercising while sick with a cold will help you get over your illness quicker than if you don’t exercise. There are currently no studies that have investigated this, largely because of how difficult it would be to conduct this type of study – mostly because some of the participants would purposely need to be infected with a virus to compare whether or not exercising has any affect. Not only would this be difficult to do, it could also be unethical.</p>
<p>So as exercise is good for the immune system, why could exercising while sick not improve the response of the immune system to the infection? Well, it’s important to remember that exercise can stress the body. This stress may in turn make the immune cells <a href="https://journals.humankinetics.com/view/journals/ijsnem/29/2/article-p181.xml?content=pdf">less capable at responding</a> to pathogens. This may be partly due to the fact that the body needs more oxygen and stored energy (in the form of glucose) when we exercise – which our immune cells also need to help fight off a virus. If the body is fighting an existing infection and then exposed to the stress of exercise this may not benefit the immune response. </p>
<p>But while there’s currently no evidence that exercising while sick with a cold can help you get over it faster, that doesn’t mean you can’t exercise if you want to. If your symptoms are <a href="https://www.gssiweb.org/en-ca/article/sse-56-contagious-infections-in-competitive-sports">mainly above the neck</a> (such as a runny nose or congestion), begin by exercising at a lower intensity than you might normally to see how your feeling. If you feel okay, you can gradually increase your intensity. But if exercising makes you feel worse, rest. It’s also not recommended for you to exercise if you’re experiencing fever, aching muscles or vomiting.</p>
<p>If you do want to exercise while you’re sick, make sure you take caution – especially if you exercise around other people. Since colds are infectious, it may be best to skip the gym and exercise outdoors or at home to avoid spreading it around.</p>
<p>Regular exercise is a great way to help prime the immune system to fight many different types of infections, including the common cold and <a href="https://bjsm.bmj.com/content/bjsports/55/19/1099.full.pdf">possibly even COVID-19</a>. But don’t feel you have to exercise if you’re sick. Sometimes the best remedy for a cold is rest, staying hydrated and taking pain-relieving medicines if needed.</p><img src="https://counter.theconversation.com/content/179803/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Hough does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As little as 30 minutes of exercise five times a week can benefit your immune system.John Hough, Senior Lecturer, Exercise Physiology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1620622021-06-03T21:02:51Z2021-06-03T21:02:51ZI’m fully vaccinated but feel sick – should I get tested for COVID-19?<figure><img src="https://images.theconversation.com/files/404344/original/file-20210603-25-rj66sq.jpg?ixlib=rb-1.1.0&rect=176%2C198%2C7172%2C3933&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some people can still get sick after getting vaccinated for COVID-19.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-sneezing-in-a-tissue-in-the-living-room-royalty-free-image/1149518691?adppopup=true">Dragana991/iStock via Getty Images Plus</a></span></figcaption></figure><p>Imagine last night you developed a little runny nose and a sore throat. When you woke up this morning you started coughing and had a fever. In the past year, your mind would have immediately jumped to COVID-19. But if you are already fully vaccinated, you might wonder: Should I still get tested for COVID-19?</p>
<p><a href="https://directory.hsc.wvu.edu/Individual/Index/31722">As an infectious disease physician</a>, I am often asked this question. The answer is yes. If you have symptoms of COVID-19, you should get tested for COVID-19 even if you are fully vaccinated. You won’t be at high risk for hospitalization or severe disease, but if you are infected you <a href="https://theconversation.com/can-people-vaccinated-against-covid-19-still-spread-the-coronavirus-161166">may pass the virus to an unvaccinated person</a>, who could then get very sick.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man wearing a mask getting his COVID-19 vaccine shot." src="https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/404348/original/file-20210603-23-24xyrr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Vaccination prevents more than 90% of severe COVID-19 cases, but researchers think that only 70%-85% of vaccinated people are completely protected from any infection.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/VirusOutbreakCaliforniaVaccine/189df2d60f4e4ad9b87b2971305a78ad/photo?Query=vaccine%20covid%20california&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=715&currentItemNo=21">AP Photo/Marcio Jose Sanchez</a></span>
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<h2>Vaccines work but aren’t 100% effective</h2>
<p>Researchers have developed some <a href="https://theconversation.com/pfizer-vaccine-what-an-efficacy-rate-above-90-really-means-149849">amazing COVID-19 vaccines over the past year</a>. The high efficacy of these vaccines in the closely controlled environment of clinical trials matches their effectiveness in real life. The mRNA vaccines made by Pfizer and Moderna remain <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7018e1.htm">over 90% effective in preventing hospitalization or death</a>.</p>
<p>That does not, however, mean that you have the same degree of protection from getting infected. </p>
<p>The latest research estimates that the mRNA vaccines offer <a href="https://doi.org/10.1016/S0140-6736(21)00870-9">70% to 85% protection from getting infected at all</a>. It’s impossible to know whether a person is fully protected or could still develop a mild case if exposed to the coronavirus. </p>
<p>If you did happen to get infected, you could still spread the virus. And that’s why testing is still important.</p>
<h2>What is a breakthrough case?</h2>
<p>When a person gets infected with the coronavirus after being fully vaccinated, this is called a breakthrough case. Breakthrough cases demonstrate a basic principle of infectious disease – whether or not a person gets infected depends on the balance between two factors: intensity of exposure and immune competence.</p>
<p><a href="https://dx.doi.org/10.1016%2Fj.mehy.2020.110431">Intensity of exposure</a> relates to how close an uninfected person is to a highly infectious individual spewing virus while talking and how long the two people are in contact. Immune competence relates to the body’s inherent protection against COVID-19. Unvaccinated individuals who’ve never been infected with the coronavirus have no protection – this is a completely new virus after all – while fully vaccinated people will be much more protected.</p>
<p>According to the CDC, as of April 30, 2021, there had been a total of <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7021e3.htm">10,262 known SARS-CoV-2 vaccine breakthrough infections</a> in U.S. states and territories. These are usually asymptomatic or only mildly symptomatic cases, and most don’t result in hospitalization. Breakthrough cases will continue to occur, and though these people are <a href="https://doi.org/10.1038/s41591-021-01316-7">less likely to spread the coronavirus to others</a> than are unvaccinated individuals, <a href="https://theconversation.com/can-people-vaccinated-against-covid-19-still-spread-the-coronavirus-161166">they still probably can</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A medical worker inserting a small swab into a man's nose." src="https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=517&fit=crop&dpr=1 754w, https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=517&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/404349/original/file-20210603-27-152lr5w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=517&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If you have symptoms of COVID-19, you should still get tested, even if you’ve already been vaccinated.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/VirusOutbreakFlorida/94a88a14f5ca47afa7963d68844fb4fa/photo?Query=covid%20test%20swab%20nose&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=163&currentItemNo=16">AP Photo/Wilfredo Lee</a></span>
</figcaption>
</figure>
<p>And what about the SARS-CoV-2 variants? Well, the world has been fortunate that the mRNA vaccines in particular <a href="https://www.cdc.gov/vaccines/covid-19/health-departments/breakthrough-cases.html">afford significant protection against all major variants</a> that have emerged so far. But it is entirely possible that at some point a <a href="https://theconversation.com/coronavirus-variants-viral-mutation-and-covid-19-vaccines-the-science-you-need-to-understand-153771">coronavirus strain could mutate</a> and <a href="https://doi.org/10.1016/S1473-3099(21)00202-4">partially or fully escape the protection from vaccines</a>. This is yet another good reason to get tested if you are feeling sick.</p>
<p>[<em>Get our best science, health and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p>
<p>As vaccination rates rise and daily case counts fall in the U.S. and other countries, it is also <a href="https://theconversation.com/genomic-surveillance-what-it-is-and-why-we-need-more-of-it-to-track-coronavirus-variants-and-help-end-the-covid-19-pandemic-157540">important to keep a close eye on the coronavirus</a>. COVID-19 testing allows officials to keep track of how much virus is in a community, and positive test results can help people quarantine before unknowingly spreading the virus to others. So, yes, please get tested if you have concerning symptoms, even if you are fully vaccinated.</p><img src="https://counter.theconversation.com/content/162062/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arif R. Sarwari does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Vaccinated people can still get infected with the coronavirus. So if you have symptoms of COVID-19, getting tested can protect others and help health officials keep an eye on the virus.Arif R. Sarwari, Physician, Associate Professor of Infectious Diseases, Chair of Department of Medicine, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1366632020-04-24T12:22:03Z2020-04-24T12:22:03ZCoronavirus drifts through the air in microscopic droplets – here’s the science of infectious aerosols<figure><img src="https://images.theconversation.com/files/330205/original/file-20200423-47794-1ypobds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">From your lungs into the air around you, aerosols carry coronavirus.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/man-with-flu-coughing-and-sneezing-royalty-free-image/148981627?adppopup=true"> Peter Dazeley/The Image Bank via Getty Images</a></span></figcaption></figure><p>During the 1970s when I was growing up in Southern California, the <a href="https://timeline.com/la-smog-pollution-4ca4bc0cc95d">air was so polluted</a> that I was regularly sent home from high school to “shelter in place.” There might not seem to be much in common between staying home due to air pollution and staying home to fight the coronavirus pandemic, but fundamentally, both have a lot to do with aerosols.</p>
<p>Aerosols are the tiny floating pieces of pollution that make up Los Angeles’ famous smog, the dust particles you see floating in a ray of sunshine and also the small droplets of liquid that escape your mouth when you talk, cough or breathe. These small pieces of floating liquids can contain pieces of the coronavirus and can be major contributor to its spread.</p>
<p>If you walk outside right now, chances are you will see people wearing masks and practicing social distancing. These actions are in large part meant to prevent people from <a href="https://www.huffpost.com/entry/face-masks-do-not-replace-social-distancing-why_l_5e970b37c5b65eae709d3fc7">spreading or inhaling aerosols</a>.</p>
<p><a href="http://shellym80304.com">I am a professor of mechanical engineering</a> and study aerosols and air pollution. The more people understand how aerosols work, the better people can avoid getting or spreading the coronavirus.</p>
<h2>Airborne and everywhere</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330207/original/file-20200423-47820-1e6axkz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aerosols are everywhere.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/child-flour-game-royalty-free-image/157329692?adppopup=true">slobo/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p>An aerosol is a clump of small liquid or solid particles floating in the air. They are everywhere in the environment and can be made of anything small enough to float, like smoke, water or coronavirus-carrying saliva. </p>
<p>When a person coughs, talks or breathes, they throw anywhere between <a href="https://dx.doi.org/10.1080%2F15459624.2012.684582">900 to 300,000 liquid particles</a> from their mouth. These particles <a href="https://doi.org/10.1016/j.jinf.2010.11.010">range in size</a> from microscopic – a thousandth the width of a hair – up to the size of a grain of fine beach sand. A cough can send them traveling at speeds <a href="https://doi.org/10.1080/02786826.2010.542785">up to 60 mph</a>. </p>
<p>Size of the particle and air currents affect how long they will stay in the air. In a still room, tiny particles like smoke can stay airborne for <a href="https://doi.org/10.1016/S1352-2310(02)00157-7">up to eight hours</a>. Larger particles fall out of the air more quickly and land on surfaces after a few minutes. </p>
<p>By simply being near other people, you are coming into constant contact with aerosols from their mouth. During a pandemic this is a little more concerning than normal. But the important question is not do exhaled aerosols exist, rather, how infectious are they? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330206/original/file-20200423-47794-1org5ed.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The coronavirus is small and easily transported by airborne particles of saliva.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/virus-on-black-background-royalty-free-image/1212421196?adppopup=true">fotograzia/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Aerosols as virus delivery systems</h2>
<p>The new coronavirus, SARS-CoV-2, is tiny, about 0.1 microns - roughly 4 millionths of an inch - in diameter. Aerosols produced by people when they breathe, talk and cough are generally between about <a href="https://dx.doi.org/10.1080%2F15459624.2012.684582">0.7 microns</a> to around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234804/pdf/jhyg00188-0053.pdf">10 microns</a> – completely invisible to the naked eye and easily able to float in air. These particles are mostly biological fluids from people’s mouths and lungs and <a href="https://doi.org/10.1002/jmv.23698">can contain bits of virus genetic material</a>. </p>
<p>Researchers don’t yet know how many individual pieces of SARS-CoV-2 an aerosol produced by an infected person’s cough might hold. But in one preprint study, meaning it is currently under peer review, researchers used a model to estimate that a person standing and speaking in a room could release up to <a href="https://doi.org/10.1101/2020.04.12.20062828">114 infectious doses per hour</a>. The researchers predict that these aerosolized bits of saliva would easily infect other people if this happened in public indoor spaces like a bank, restaurant or pharmacy.</p>
<p>Another thing to consider is how easy these particles are to inhale. In a recent computer model study, researchers found that people would most likely inhale aerosols from another person that is talking and coughing while sitting <a href="https://doi.org/10.1016/j.buildenv.2020.106859">less than 6 feet away</a>.</p>
<p>While this seems bad, the actual process from exposure to infection is a <a href="https://theconversation.com/what-we-do-and-do-not-know-about-covid-19s-infectious-dose-and-viral-load-135991">complicated numbers game</a>. Often, viral particles found in aerosols are damaged. A study looking at the flu virus found that only <a href="https://dx.doi.org/10.1371%2Fjournal.ppat.1003205">0.1% of viruses</a> exhaled by a person are actually infectious. The coronavirus also starts to die off once it has left the body, remaining viable in the air for <a href="https://doi.org/10.1056/NEJMc2004973">up to three hours</a>. And of course, not every aerosol coming from an infected person will contain the coronavirus. There is a lot of chance involved.</p>
<p>Public health officials still don’t know whether direct contact, indirect contact through surfaces, or aerosols are the main <a href="https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-019-3707-y">pathway of transmission</a> for the coronavirus. But everything experts like myself know about aerosols suggests that they could be a major pathway of transmission.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330242/original/file-20200423-47841-zm8fap.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aerosol driven outbreaks have been linked to restaurants, shops and many other public places.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Hong-Kong-China-Outbreak/37408763dcd441db9dad9180db4377f2/69/0">AP Photo/Vincent Yu</a></span>
</figcaption>
</figure>
<h2>Evidence of aerosol transmission</h2>
<p>It is almost impossible to study viral transmission in real time, so researchers have turned to environmental sampling and contact tracing to try to study the spread of the coronavirus in aerosols. This research is happening extremely fast and most of it is still under peer review, but these studies offer extremely interesting, if preliminary, information. </p>
<p>To test the environment, researchers simply sample the air. In Nebraska, scientists found <a href="https://doi.org/10.1101/2020.03.23.20039446">airborne SARS-CoV-2 in a hospital</a>. In China, scientists also found the virus in the air of <a href="https://doi.org/10.1101/2020.03.08.982637">a number of hospitals as well as a department store</a>. </p>
<p>But environmental sampling alone cannot prove aerosol transmission. That requires contact tracing.</p>
<p>One restaurant in Guangzhou, China, was the site of a small outbreak on Jan. 23 and offers direct evidence of aerosol transmission. <a href="https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article">Researchers</a> believe that there was one infected but asymptomatic person sitting at a table in the restaurant. Because of the air currents circulating in the room due to air conditioning, people sitting at two other tables became infected, <a href="https://doi.org/10.1101/2020.04.16.20067728">likely because of aerosols</a>. </p>
<p>Overall, the evidence suggests that it is much <a href="https://www.nationalreview.com/corner/coronavirus-transmission-chinese-study-shows-covid-more-likely-spread-indoors/">more risky to be inside</a> than outside. The reason is the lack of airflow. It takes between <a href="https://www.aivc.org/sites/default/files/airbase_4213.pdf">15 minutes and three hours</a> for an aerosol to be sucked outside <a href="https://www.ncbi.nlm.nih.gov/books/NBK143277/">by a ventilation system</a> or float out an open window.</p>
<p>Another preprint study of outbreaks in Japan suggests that the chances of direct transmission are almost <a href="https://doi.org/10.1101/2020.02.28.20029272">20 times higher indoors compared</a> to outdoors. In Singapore, researchers traced the first three outbreaks directly to a <a href="https://doi.org/10.1016/S0140-6736(20)30528-6">few shops, a banquet dinner and a church</a>. </p>
<p>Once outside, these potentially infectious aerosols disappear in the expanse of the atmosphere and are much less of a worry. It is of course possible to catch the virus outside if you are in close contact with a sick person, but this seems very rare. Researchers in China found that only <a href="https://doi.org/10.1101/2020.04.04.20053058">one of 314 outbreaks</a> they examined could be traced back to outdoor contact. </p>
<p>There has been recent concern over <a href="https://www.wired.com/story/are-running-or-cycling-actually-risks-for-spreading-covid-19/">aerosol transmission during running and biking</a>. While the science is still developing on this, it is probably wise to give other bikers or runners a little more room than normal.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330208/original/file-20200423-47810-1n1kzds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wearing masks and social distancing reduce the risk of spreading or inhaling aerosols.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Virus-Outbreak-Louisiana/bb82598420d646edbce881537b399efa/88/0">AP Photo/Gerald Herbert</a></span>
</figcaption>
</figure>
<h2>How to reduce aerosol transmission</h2>
<p>With all of this knowledge of how aerosols are produced, how they move and the role they play in this pandemic, an obvious question arises: what about masks?</p>
<p>The Centers for Disease Control and Prevention recommends wearing a face mask in <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html">any public setting</a> where social distancing is hard to do. This is because homemade masks probably do a reasonable job of blocking aerosols from leaving your mouth. The evidence <a href="https://theconversation.com/why-wear-face-masks-in-public-heres-what-the-research-shows-135623">generally supports their use</a> and more research is coming to show that masks can be very effective at <a href="https://doi.org/10.5061/dryad.w9ghx3fkt">reducing SARS-CoV-2 in air</a>. Masks aren’t perfect and more studies are currently underway to learn how effective they really are, but taking <a href="https://doi.org/10.1136/bmj.m1435">this small precaution</a> could help slow the pandemic. </p>
<p>Other than wearing a mask, follow common sense and the <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/index.html">guidance of public health officials</a>. Avoid crowded indoor spaces as much as possible. Practice social distancing both inside and outdoors. Wash your hands frequently. All of these things work to prevent the spread of the coronavirus and can help keep you from getting it. There is a significant amount of evidence that COVID-19 is transmitted by the inhalation of airborne particles, but by carefully following the advice of experts, individuals can minimize the risk they pose.</p>
<p>[<em>Get facts about coronavirus and the latest research.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=upper-coronavirus-facts">Sign up for The Conversation’s newsletter.</a>]</p><img src="https://counter.theconversation.com/content/136663/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shelly Miller does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Aerosols are the tiny particles of liquid and material that float around in our environment. When they come from an infected person, they may be a significant source of coronavirus transmission.Shelly Miller, Professor of Mechanical Engineering, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1330542020-03-17T19:46:25Z2020-03-17T19:46:25ZViruses live on doorknobs and phones and can get you sick – smart cleaning and good habits can help protect you<figure><img src="https://images.theconversation.com/files/320286/original/file-20200312-111300-zgdow6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Disinfecting an area takes time and effort. And there is only so much you can do. </span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Virus-Outbreak-New-York/4af925c106ca40268d5db383657b355e/2/0">AP Photo/Seth Wenig</a></span></figcaption></figure><p>One vomiting episode from someone infected with norovirus <a href="https://dx.doi.org/10.3201/eid1410.080117">emits billions and billions of individual viruses</a>. That’s enough to fuel an outbreak – and is exactly what happened in an elementary school in <a href="https://www.usatoday.com/story/news/health/2019/12/13/norovirus-outbreak-stomach-flu-terrorizes-washington-public-schools/4417867002/">Seattle, Washington a few months ago</a>. Over 100 children got sick with the stomach-churning bug, and the school doors remained closed until workers could decontaminate the lockers, desks and hallways.</p>
<p>You might think of germs mostly passing directly from one person to another, but the outbreak in Seattle illustrates how they can survive on and be transmitted by inanimate objects in the world around us. <a href="https://sph.umich.edu/faculty-profiles/eisenberg-joseph.html">Epidemiologists like me</a> call these everyday objects – like doorknobs, elevator buttons and cellphones – fomites, and when contaminated, these fomites can make you sick. </p>
<p>Fomites can be an important pathway of disease transmission. They were the main culprits in that norovirus outbreak in Seattle last year and have been the cause of many other outbreaks. In 1908, <a href="https://dx.doi.org/10.1128%2FAEM.02051-06">smallpox outbreaks were traced to contaminated imported cotton</a>. More recently, <a href="https://doi.org/10.1093/oxfordjournals.aje.a113661">outbreak studies in day care centers</a> have identified viruses on <a href="https://www.ncbi.nlm.nih.gov/pubmed/8393172">toys, phones, toilet handles, sinks and water fountains</a>.</p>
<h2>The novel coronavirus</h2>
<p>The coronavirus is spreading quickly. As concern has increased, I’ve seen more people washing their hands and using hand sanitizer than ever before. While there is still a lot we don’t know about the new coronavirus, SARS-CoV-2, history would suggest that there is probably some transmission from fomites. Everyone should be washing their hands and using hand sanitzer, but taking efforts to clean the things around you is also important to fight the spread of the virus.</p>
<p>For instance, in the last major coronavirus pandemic, SARS in 2002, contaminated surfaces were a major contributor to over <a href="https://dx.doi.org/10.1258%2Fjrsm.96.8.374">300 cases in a Hong Kong apartment building</a>.</p>
<p>When thinking about how risky transmission via fomites is in an outbreak, the important question is how long can a particular bug survive on surfaces. And there is a lot of variation. Some pathogens can last outside the body for only minutes, while others are hardier and can hold on for days or even months. A new study suggests that the novel coronavirus <a href="https://doi.org/10.1101/2020.03.09.20033217">can survive on some surfaces up to three days</a>, but it varies depending on the material. The study found that the virus could survive for 24 hours on cardboard and up to three days on plastic and stainless steel.</p>
<p>This variation is caused in part by the <a href="https://doi.org/10.1186/1471-2334-6-130">properties of the surface a virus lands on</a>. Porous material like clothing may allow pathogens to survive longer but it can be harder for a virus to move <a href="https://doi.org/10.1128/AEM.01030-13">from your shirt to someone else’s fingers</a>. The matrix fibers in nonporous materials can trap germs making it hard for them to transfer. On the other hand, viruses can more readily transfer from nonporous materials like the glass screen on your phone to fingers, but the virus won’t always survive as long on a glass surface compared to a sweater.</p>
<p>Environmental conditions such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC201876/">temperature and humidity also influence the viability of a pathogen in the environment</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/320291/original/file-20200312-111268-3h808r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Most viruses will eventually die on their own. But cleaning with alcohol, bleach and other chemicals can kill them more quickly.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Ukraine-Virus-Outbreak/6b99329a97094a578d3b689b6f5d9924/20/0">AP Photo/Efrem Lukatsky</a></span>
</figcaption>
</figure>
<h2>Persistent bugs and how to get rid of them</h2>
<p>It’s nearly impossible to keep anything in the real world virus-free, but during outbreaks like this one it’s a good idea to try to minimize the number of viruses on fomites around you. Some people are practically bathing in hand sanitizer and wiping down everything they touch with disinfectant. But whether this works depends on what virus you are hoping to kill.</p>
<p>Norovirus, for example, is notoriously hardy. After an outbreak on a cruise ship in 2002, the next group of passengers got sick <a href="https://dx.doi.org/10.3201%2Feid1101.040434">more than a week later after a thorough cleaning of the ship</a>. Many standard cleaners like alcohol or Lysol do not kill norovirus. It takes something as strong as chlorine bleach to get the job done. </p>
<p>In contrast to norovirus, <a href="https://dx.doi.org/10.1128%2FAEM.02051-06">influenza is much less persistent in the environment</a>. While influenza is often lurking in daycare centers during flu season, it typically lasts on surfaces only for hours or a few days. And if you wanted to clean off your phone or countertop, simply wiping it down with an alcohol-based product or ammonia is effective.</p>
<p>While virologists don’t know much about how tough the current coronavirus is, past coronaviruses have fallen somewhere between norovirus and the flu. Like influenza, Lysol will likely kill the coronavirus.</p>
<p>But you don’t necessarily need to kill the virus to make yourself safer. Removing the virus can be just as effective and simply <a href="https://www.cdc.gov/handwashing/show-me-the-science-hand-sanitizer.html">washing often-used objects or your hands with soap can do that</a>.</p>
<p>If you have been in crowded areas or want to be extra careful, washing your hands with soap for 20 seconds will effectively remove germs, and disinfecting tabletops and gym equipment with ammonia will effectively kill most germs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/320289/original/file-20200312-111237-38wj0i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Viruses are on everything. How you behave around them matters.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/asian-woman-with-protective-face-mask-using-royalty-free-image/1203348066?adppopup=true">d3sign/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>What can you do in a world with viruses everywhere?</h2>
<p>During the coronavirus pandemic, it is important to clean the objects you touch frequently, like keyboards, tabletops and gym equipment.</p>
<p>But while fomites are known to be the culprits in many outbreaks, an individual’s risk depends on a lot of factors. Someone who touches contaminated surfaces frequently, like a health care worker, <a href="https://www.nytimes.com/interactive/2020/03/15/business/economy/coronavirus-worker-risk.html">is more likely to get sick than someone who doesn’t</a>. Risk also depends on personal habits, such as how often one touches their eyes, nose and mouth. And for most infectious diseases, whether someone gets sick and the severity of the illness depends on age and underlying health conditions.</p>
<p>Cleaning objects frequently with a disinfectant is the best way to mitigate the risk of transmission from everyday objects. Hand-washing is also important, especially if done reliably right after coming home from a public place.</p>
<p>Given that germs are ubiquitous, it’s easy to become germ-phobic and strive for a sterile environment. But keep in mind that while basic precautions are important, germs will always find a way to exploit our human environment. You can and should minimize risk, but germs are here to stay. </p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>.]</p><img src="https://counter.theconversation.com/content/133054/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joseph Eisenberg does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The coronavirus, like many infectious diseases, can live and spread on inanimate objects in the world around us. An epidemiologist explains how and gives some advice on how to minimize the risk.Joseph Eisenberg, Professor and Chair of Epidemiology, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1283702020-02-20T12:17:45Z2020-02-20T12:17:45ZDo I have to wear a jacket when it’s cold outside?<figure><img src="https://images.theconversation.com/files/315565/original/file-20200215-11000-1f9iyib.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5220%2C3631&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's an age-old battle between parents and kids.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/photo-teenage-friends-red-christmas-sweaters-1265217739">Alena Ozerova/Shutterstock.com</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Will I get sick if I go out in the cold without a jacket? – Ben P., age 4, South Orange, New Jersey</strong></p>
</blockquote>
<hr>
<p>The answer to this question is: “It depends.”</p>
<p>Cold weather does not get you sick. Feeling chilly because you’re not bundled up does not get you sick.</p>
<p>But being cold – like when you’re outside in wintry weather wearing just a thin shirt – can actually weaken your body and make it easier for you to get sick. Researchers have shown that <a href="https://doi.org/10.1016/j.wem.2011.08.005">cold temperatures weaken your immune system</a> and thus your ability to fight off infections. In fact, the longer time you spend in the cold, the higher your risk of actually getting sick.</p>
<p>To get sick, though, you still must be exposed to a germ. So it’s key to avoid coming into contact with germs as well. Unfortunately, that’s easier said than done.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315566/original/file-20200215-10980-1gq2rix.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscopic bacteria and viruses are all around, ready to invade your body’s cells and make you sick.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/bacteria-viruses-on-surface-skin-mucous-297732359">Kateryna Kon/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>There are <a href="https://www.nih.gov/news-events/nih-research-matters/understanding-common-cold-virus">over 200 viruses that can cause a cold</a>. These viruses are all around us. In the wintertime, people often stay indoors and are closer together in general, which encourages the spread of viruses.</p>
<p>One called rhinovirus is responsible for around a <a href="https://www.nih.gov/news-events/nih-research-matters/understanding-common-cold-virus">third of the cases of runny noses and congestion</a>, but can also cause more serious lung diseases. There’s another group of germs, called <a href="https://www.cdc.gov/coronavirus/types.html">human coronaviruses</a>, that can make you sick. The <a href="https://theconversation.com/us/topics/coronavirus-5830">new virus named 2019-nCoV</a> is one of these.</p>
<p>The cold, <a href="https://doi.org/10.1017/S0022172400039176">dry weather</a> does <a href="https://www.popsci.com/science/article/2013-01/fyi-why-winter-flu-season/">play a role in winter sniffles</a>, because it can strengthen these virus invaders. For example, viruses survive longer and multiply faster in the <a href="https://www.sciencedaily.com/releases/2015/01/150105170014.htm">cooler regions of your nasal passages</a>.</p>
<p>Cooler temperatures also tend to <a href="https://doi.org/10.1073/pnas.1411030112">weaken your body’s antiviral immune responses</a>. In fact, a fever helps your body warm up and invigorates your immune system cells to fight infection.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315299/original/file-20200213-10985-10aa4ur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An uncovered sneeze blasts germs into the air for other people to breathe in.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=11162">CDC/Brian Judd</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Viruses live in the environment all around you. They’re on surfaces such as doorknobs. They’re in the air after someone sneezes. The most common way to expose yourself to these germs is by inhaling virus-filled air or touching your eyes or nose with dirty hands. </p>
<p>The <a href="https://www.cdc.gov/features/rhinoviruses/index.html">best way to avoid catching a cold</a> is to wash your hands as often as possible, avoid anyone who is clearly sick and keep your immune system strong. Tips for boosting your body’s immune power include eating a well-balanced diet, having a healthy sleep routine, balancing stress with enjoyable activities and keeping warm to minimize susceptibility to infection. Don’t forget vaccines are available to help keep you from getting sick with certain viruses, <a href="https://www.cdc.gov/flu/prevent/vaccinations.htm">including influenza</a>.</p>
<p>If you do catch a cold, it is best to rest, drink plenty of water and contact your doctor for any worsening symptoms. And if you go outside in the cold, be sure to bundle up and try to stay warm.</p>
<hr>
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<p class="fine-print"><em><span>Carolyn Kaloostian does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Leaving your coat at home on a cold winter day doesn’t automatically mean you’re going to get sick. But it could make you more susceptible to germs.Carolyn Kaloostian, Clinical Assistant Professor of Family Medicine, University of Southern CaliforniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1297422020-02-13T14:04:19Z2020-02-13T14:04:19ZHow to convince your loved ones to get the flu shot this year<figure><img src="https://images.theconversation.com/files/309773/original/file-20200113-103979-1txdvzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Studies show that people are more likely to get the flu shot if they have a plan.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/concept-image-calendar-red-push-pin-273450770">xtock/Shutterstock.com</a></span></figcaption></figure><p>The best way to <a href="https://www.cdc.gov/flu/prevent/actions-prevent-flu.htm">protect against the flu is the flu vaccine</a>. But even so, <a href="http://thenationshealth.aphapublications.org/content/47/9/E45">about 60% of Americans will skip</a> getting a flu shot this year.</p>
<p>This can be especially frustrating when it is a friend or loved one who is putting themselves and those around them at risk. <a href="https://www.researchgate.net/scientific-contributions/2163348560_Helen_Colby">We are</a> <a href="https://clas.ucdenver.edu/hbsc/meng-li">behavioral scientists</a>, and we wanted to know: How do you convince someone to get the vaccine?</p>
<p>The flu shot doesn’t just benefit the person who gets it. It also <a href="https://www.pbs.org/wgbh/nova/article/herd-immunity/">helps protect everyone around the vaccinated person</a>, <a href="https://www.cdc.gov/flu/prevent/whoshouldvax.htm">such as the very young, the very old and people whose immune systems are compromised</a>. People in these groups often cannot get the vaccine, or it is less effective for them.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/m6b5z1CIEZE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The CDC warns viewers to get the flu shot.</span></figcaption>
</figure>
<h2>It’s a bargain</h2>
<p>We would love to tell you that a logical presentation of facts like those we listed above is the best method for convincing someone. Unfortunately, <a href="https://www.cnbc.com/2018/11/02/heres-why-people-dont-get-a-flu-shot-and-why-you-should.html">it usually isn’t</a>.</p>
<p>It really seems like we should just be able to tell our spouse, uncle or babysitter how the vaccine works, what it does for us and why it’s important, and then, watch them run straight to the nearest immunization clinic.</p>
<p>The surprising truth is that telling people the facts about the flu shot just doesn’t work.</p>
<p>However, <a href="https://hub.kelley.iupui.edu/news/_news/kelley-professor-studying-what-works-and-what-doesnt-in-health-advertising-and-messaging.html">our research</a>, funded by the <a href="https://www.rwjf.org/en/library/funding-opportunities/2019/evidence-for-action-investigator-initiated-research-to-build-a-culture-of-health.html_">Robert Wood Johnson Evidence For Action program</a>, has found that showcasing the flu shot in different ways – like explaining <a href="https://www.cdc.gov/vaccines/programs/vfc/awardees/vaccine-management/price-list/index.html">what a good deal it is</a> – can be much more convincing.</p>
<p>For instance, even though the true cost of getting a flu shot is typically between US$40 and $70, most people can receive one free or for about $10 by using insurance, an employer’s program or finding a community clinic.</p>
<p>That’s a 75% to 100% savings. If televisions were offered at that discount, people would be lined up out the door of Best Buy. </p>
<p>These studies have shown that some of the consumer excitement people feel when getting great discounts on household goods can be transferred to preventive care activities, like flu shots.</p>
<p>Reminding people what a great deal flu shots are is a much more effective strategy to increase interest than listing the health and societal benefits. In our studies, it’s been even more effective than showing <a href="https://www.youtube.com/watch?v=m6b5z1CIEZE">a 30-second informational video</a> about flu shots from the CDC website.</p>
<h2>When and where?</h2>
<p>So now your friend or loved one is a little more interested, maybe even willing to get the shot. How do you make sure they will follow through?</p>
<p>If it’s your spouse or child, you might be able to make them an appointment.</p>
<p>In a separate set of studies, <a href="https://jamanetwork.com/journals/jama/fullarticle/186162?resultClick=1">we found</a> that signing up people for a specific date and time to get a flu shot – without asking them for convenient dates or knowing anything about their schedules – was 36% more effective at driving flu shot uptake than sending an email that asked people to click to make an appointment.</p>
<p>Even though some people changed their appointment date or time, and some didn’t show up, more people who received a randomly assigned appointment got the flu shot than those who had to make their own appointments.</p>
<p>If you can’t just make them an appointment, you can also nudge them to create what’s called an “<a href="https://www.psychologytoday.com/us/blog/dont-delay/201001/implementation-intentions-facilitate-action-control">implementation intention</a>,” or a concrete, specific set of plans about when and where something will happen.</p>
<p>Implementation intentions <a href="https://doi.org/10.1073/pnas.1103170108">increase the likelihood of getting</a> the flu shot by as much as 4.2%. For example, will they go to the pharmacy near their house for the vaccine? When will they do it?</p>
<p>Tying it to specific activities can help them remember – like “after dropping off the kids at soccer practice on Saturday morning I will stop by the CVS on the corner of Main Street to get a flu shot” – is a great implementation intention.</p>
<p>Help the person develop an implementation intention by asking simple questions or making suggestions about when and where they might be able to get the vaccine.</p>
<p>Encouraging them to write them down – or even better, set a reminder in their phone or calendar – can also be helpful.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309774/original/file-20200113-103966-1p5lowt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Getting the flu shot helps people who are most susceptible to the flu, like kids.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/doctor-makes-vaccination-391419913">CNK02/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>The flu is no joke</h2>
<p>Though the optimal time to get a flu shot is much earlier <a href="https://www.cdc.gov/flu/about/season/flu-season.htm">during the flu season</a>, it is not too late to get the shot, as the season sometimes goes as late as May.</p>
<p>The <a href="https://www.scientificamerican.com/article/how-does-the-flu-actually-kill-people/">flu kills hundreds of thousands</a> of people every year around the world and <a href="https://www.waukeshapediatrics.com/blog/post/cold-vs-flu.html">debilitates millions more</a>. The best prevention is getting the flu vaccine.</p>
<p>But if presenting the facts to your friends and family isn’t encouraging them to get the shot, try emphasizing the great value, making appointments for them or encouraging them to set and record concrete implementation intentions.</p>
<p>They will protect their health and get a great bargain too.</p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/129742/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Helen Colby receives funding from the Robert Wood Johnson Foundation. </span></em></p><p class="fine-print"><em><span>Meng Li receives funding from the Robert Wood Johnson Foundation. </span></em></p>The flu shot is a bargain – and people are more likely to get it if they know that.Helen Colby, Assistant Professor of Marketing, IUPUIMeng Li, Associate Professor of Health and Behavioral Sciences, University of Colorado DenverLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1269152019-12-17T13:53:50Z2019-12-17T13:53:50ZFeeling sick is an emotion meant to help you get better faster<figure><img src="https://images.theconversation.com/files/307274/original/file-20191216-123987-1po4o1j.jpg?ixlib=rb-1.1.0&rect=840%2C269%2C6344%2C4523&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The emotion of lassitude might help your body fight off infection by making certain adjustments.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sick-boy-thermometer-laying-bed-child-1478490944">Kalinka Georgieva/Shutterstock.com</a></span></figcaption></figure><p>You know what it’s like to be sick. You feel fatigued, maybe a little depressed, less hungry than usual, more easily nauseated and perhaps more sensitive to pain and cold.</p>
<p>The fact that illness comes with a distinct set of psychological and behavioral features is not a new discovery. In medical terminology, the <a href="https://medlineplus.gov/ency/article/003089.htm">symptom of malaise</a> encompasses some of the feelings that come with being ill. Animal behaviorists and neuroimmunologists use the term <a href="https://doi.org/10.1093/icb/icp028">sickness behavior</a> to describe the observable behavior changes that occur during illness.</p>
<p>Health care providers often treat these symptoms as little more than annoying side effects of having an infectious disease. But as it turns out, these changes may actually be part of how you fight off infection.</p>
<p><a href="https://scholar.google.com/citations?user=qXvC94wAAAAJ&hl=en&oi=ao">I’m an anthropologist</a> interested in how illness and infection have shaped human evolution. My colleagues and I propose that all these aspects of being sick are features of an <a href="https://doi.org/10.1016/j.evolhumbehav.2019.09.002">emotion that we call “lassitude.”</a> And it’s an important part of how human beings work to recover from illness.</p>
<h2>Your body sets priorities when fighting germs</h2>
<p>The human immune system is a <a href="https://doi.org/10.1056/NEJM200007063430107">complex set of mechanisms</a> that help you suppress and eliminate organisms – such as bacteria, viruses and parasitic worms – that cause infection.</p>
<p>Activating the immune system, however, <a href="https://doi.org/10.1002/ajhb.21045">costs your body a lot of energy</a>. This presents a series of problems that your brain and body must solve to fight against infection most effectively. Where will this extra energy come from? What should you do to avoid additional infections or injuries that would increase the immune system’s energy requirements even more?</p>
<p>Fever is a critical part of the immune response to some infections, but the <a href="https://www.ncbi.nlm.nih.gov/books/NBK331/">energy cost of raising your temperature is particularly high</a>. Is there anything you can do to reduce this cost? </p>
<p>To eat or not to eat is a choice that affects your body’s fight against infection. On one hand, food ultimately provides energy to your body, and some foods even contain compounds that may <a href="https://doi.org/10.1016/S2221-1691(11)60016-6">help eliminate pathogens</a>. But it also <a href="https://doi.org/10.1186/1743-7075-1-5">takes energy to digest food</a>, which diverts resources from your all-out immune effort. Consuming food also increases your risk of acquiring additional pathogens. So what should you eat when you’re sick, and how much?</p>
<p>We humans are highly dependent on others to <a href="https://doi.org/10.1002/ajpa.10325">care for and support us when we’re sick</a>. What should you do to <a href="https://doi.org/10.1177/1474704915600559">make sure your friends and family care for you</a> when you’re ill?</p>
<p>My colleagues and I propose that the distinctive changes that occur when you get sick <a href="https://doi.org/10.1016/j.evolhumbehav.2019.09.002">help you solve these problems</a> automatically.</p>
<ul>
<li>Fatigue reduces your level of physical activity, which leaves more energy available for the immune system.</li>
<li>Increased susceptibility to nausea and pain makes you less likely to acquire an infection or injury that would further increase the immune system’s workload.</li>
<li>Increased sensitivity to cold motivates you to seek out things like warm clothing and heat sources that reduce the costs of keeping body temperature up.</li>
<li>Changes in appetite and food preferences push you to eat (or not eat) in a way that supports the fight against infection.</li>
<li>Feelings of sadness, depression and general wretchedness provide an honest signal to your friends and family that you need help.</li>
</ul>
<p>Of course these changes depend on the context. Any parents reading this article are likely familiar with the experience of being sick but pushing through it because a child needs care. While it may make sense to reduce food intake to prioritize immunity when the sick individual has plenty of energy reserves, it would be counterproductive to avoid eating if the sick person is <a href="https://doi.org/10.1016/j.bbi.2014.01.005">on the verge of starvation</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307275/original/file-20191216-124009-swa2ry.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Your body needs you to do (or avoid) a few things so it can concentrate on getting better.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/black-woman-feeling-sick-seasonal-flu-1201292887">tommaso79/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Sickness as an emotion</h2>
<p>So how does your body organize these advantageous responses to infection?</p>
<p>The evidence my colleagues and I reviewed suggests that humans possess a regulatory program that lies in wait, scanning for indicators that infectious disease is present. When it detects signs of infection, the program sends a signal to various functional mechanisms in the brain and body. They in turn change their patterns of operation in ways that are useful for fighting infection. These changes, in combination with each other, produce the distinct experience of being sick.</p>
<p>This kind of coordinating program is <a href="https://doi.org/10.1080/1047840X.2017.1256132">what some psychologists call an emotion</a>: an evolved computational program that detects indicators of a specific recurrent situation. When the certain situation arises, the emotion orchestrates relevant behavioral and physiological mechanisms that help address the problems at hand. </p>
<p>Imagine you’re walking through the woods, thinking you’re alone, and suddenly you are startled by sounds suggesting a large animal is in the underbrush nearby. Your pupils dilate, your hearing becomes attuned to every little sound, your cardiovascular system starts to work harder in preparation for either running away or defending yourself. These coordinated physiological and behavioral changes are produced by an underlying emotion program that corresponds to what you might think of as a certain kind of fear.</p>
<p>Some of these coordinating programs line up nicely with general intuitions about what makes up an emotion. Others have functions and features that we might not typically think of as “emotional.”</p>
<p>Some psychologists suggest these emotion programs likely evolved to respond to identifiable <a href="https://doi.org/10.1016/0162-3095(90)90017-Z">situations that occurred reliably over evolutionary time</a>, that would affect the survival or reproduction of those involved.</p>
<p>This way of thinking has helped researchers understand why some emotions exist and how they work. For instance, the <a href="https://doi.org/10.1098/rstb.2017.0203">pathogen disgust program</a> detects indicators that some potentially infectious agent is nearby. Imagine you smell the stench of feces: The emotion of disgust coordinates your behavior and physiology in ways that help you avoid the risky entity.</p>
<p>Another example is the <a href="https://doi.org/10.1073/pnas.1514699113">emotion of shame</a>, which scouts for signs that you’ve done something that causes members of your social group <a href="https://doi.org/10.1016/j.evolhumbehav.2018.05.010">to devalue you</a>. When you detect one of these indicators – a loved one rebukes you for doing something that hurt them, say – the experience of shame helps you adjust your mental map of what kinds of things will cause others to devalue you. Presumably you will try to avoid them in the future.</p>
<p>Drawing from the emerging discipline of <a href="https://doi.org/10.1093/emph/eox025">evolutionary medicine</a>, my colleagues and I now apply the idea of these emotion programs to the experience of being sick. We call this emotion “lassitude” to distinguish the underlying program from the outputs it generates, such as sickness behavior and malaise.</p>
<p>We hope that our approach to lassitude will help solve problems of practical importance. From a medical perspective, it would be useful to know when lassitude is doing its job and when it is malfunctioning. Health care providers would then have a better sense of when they ought intervene to block certain parts of lassitude and when they should let them be.</p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/126915/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joshua Schrock has received funding from the Wenner-Gren Foundation. </span></em></p>Fighting off infection comes with predictable psychological and behavioral features. Now researchers suggest an emotion coordinates this response to help you get better. They call it ‘lassitude.’Joshua Schrock, Ph.D. Candidate in Anthropology, University of OregonLicensed as Creative Commons – attribution, no derivatives.