Extra year of secondary schooling reduces HIV rates in Botswana

US First Lady Michelle Obama visits a centre in Botswana that supports young people affected by HIV. Botswana has one of the highest HIV infection rates in the world. Charles Dharapak/Reuters

The association between school and HIV risk has been fiercely debated for more than two decades. It has long been suggested that formal education acts as a “social vaccine” to reduce the spread of HIV because it may give young people more information about the virus and how to protect themselves from getting infected.

But it has proved difficult to isolate the effect of education on HIV risk from the complex web of other causal factors like personal motivation, psychological traits, socioeconomic status, and family background.

Our [new study](http://www.thelancet.com/journals/langlo/article/PIIS2214-109X(1500087-X/fulltext), published in The Lancet Global Health, presents what we believe is the first causal evidence that formal schooling is an important structural determinant of HIV infection and that this relationship is causal.

The study, conducted by a research team based at the Harvard T.H. Chan School of Public Health, Boston University and the Botswana Harvard Partnership, found that an extra year of secondary school reduces the risk of acquiring HIV – especially for girls.

Botswana’s HIV landscape

There have been huge strides in the fight against HIV, but it remains a major issue in global health. More than two million people are newly infected each year. In Botswana in 2013 about 22% of people aged between 15 and 49 were HIV positive, which means the country has one of the highest infection rates in the world.

Where there is no large-scale trial data, quantitative social scientists sometimes use a statistical technique that exploits “natural experiments” to evaluate causal links. Our research used this technique, examining a 1996 school reform that made it required for pupils in Botswana to complete grade 10 in order to obtain a junior secondary certificate.

One of the other impacts of the policy is that some students who stayed on to grade 10 likely discovered that they enjoyed school and wanted to stay on through grades 11 and 12. The policy resulted in almost one year of additional schooling among teens.

Using data from about 7000 people who participated in Botswana’s AIDS Impact Surveys, our research compared those who were young enough to have benefited from the school reform with those who were not. It looked at their HIV status about a decade after finishing school.

From this, it emerged that spending the additional year in secondary school lowered the risk of HIV infection among students by about a third a decade later. The effects were particularly strong for women.

But how does it work?

The question is exactly how formal education lowers HIV risk. Botswana did not have a national HIV education curriculum in 1996, so what we see is not the effect of HIV-specific education, but education more generally. So what do people gain or develop when they spend more time in school?

More education may improve job prospects, which might be especially important for women. In sub-Saharan Africa, women frequently find themselves in economically dependent sexual relationships where they don’t necessarily have enough power to insist on condom use or avoid HIV infection risk in other ways.

Research has also showed that girls who complete primary and secondary education have fewer unwanted pregnancies, which suggests they may engage more often in safe sex.

The additional schooling may also be improving cognitive skills that help people make better decisions. Students at that age are forming a sense of who they are and what their future is going to be: will they have a career, focus on finding a spouse and starting a family, or a combination of these paths?

At this point we do not know the answer, but upcoming research will address the causal pathways between formal schooling and HIV infection risk.

These results suggest that improving access to secondary schooling should be considered alongside circumcision and treatment as prevention as mainstays in combination HIV prevention strategies in countries where there is a high prevalence of HIV.

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