Current plans to eradicate polio mean keeping the virus alive – and risk restarting the epidemic.
A polio patient in an iron lung, 1940.
Vaccination is not to be taken for granted.
A boy in Pakistan receives oral polio vaccine in July.
Polio for years has been close to becoming eradicated, with the entire continent of Africa going two years without a reported case – until early August. Here's why eradication is hard but attainable.
Nigerian women who formed part of the country’s previous polio immunisation campaign.
Global Polio Eradication Initiative
A new polio outbreak in Nigeria has hampered the country's efforts to be declared polio free by 2017.
Afghanistan and Pakistan are the only two countries that still have endemic levels of polio.
Eradicating the last 1% of polio cases in the world requires an endgame plan centred on immunisation and surveillance.
The Nigerian commissioner for health of Bauchi state, Sani Malam, administers a polio vaccine to a child during an immunisation drive.
The positive impact of the polio eradication initiatives on the continent can be felt across the health sector in other health programmes.
A health worker vaccinates children with drops of polio vaccine in a classroom in Lagos, Nigeria.
Nigeria's strategy to eliminate polio was so effective that it was duplicated to deal with ebola. So why did the country take so long to get off the list of polio-endemic countries?
Senegalese Mamou Tiang, who suffers from polio, begs for money outside a bank on a sidewalk in the capital Dakar.
It's been one year since the last polio case was reported in Africa. If the continent keeps this up, it could be declared polio free by 2018.