Nigeria polio-free year sees Africa inch closer to eradication Against all odds, Nigeria has had no new polio cases in the past 12 months. Somalia will reach that milestone on 11 August � at which point all of Africa will have been polio free for a year.

The World Health Organization is still checking samples from the last suspected cases in Nigeria, but once it has confirmed them as negative, it can officially take Nigeria off the list of countries where the disease is endemic. Oliver Rosenbaum of the WHO says this could happen by September.

Nigeria success hasn�t been easy. The vaccination drive has been dogged by political corruption, rumours the vaccine was contaminated with HIV and violence � nine health workers were killed by terrorist group Boko Haram in 2013.

Nigeria has come close to eradicating the disease several times before, only for it to re-emerge. But this is the longest the country has gone without reporting a case, says Rosenbaum.

The road to zero cases
The only places where the disease still circulates regularly are Afghanistan and Pakistan, which have reported 5 and 28 cases of polio respectively this year. For each of these, there will be around 199 other people who are infected but symptomless, spreading the virus. A handful of other countries such as Somalia, Iraq and EG occasionally report the odd case, but not enough so that the disease would be considered endemic there.

Both Afghanistan and Pakistan are making progress with their vaccination campaigns, but too many children are missed, partly due to the difficulties in reaching people in rural areas with poor infrastructure, or in areas of conflict. A lack of international funding for the vaccination campaigns is also a problem, says Rosenbaum.

Nigeria won�t be able to rest on its laurels � as long as the virus is still circulating somewhere in the world, there is a chance it could return. �This is an eradication project, and unless we get to zero cases we�re not going to finish this disease,� says Rosenbaum. �Nigeria will need to keep immunising and protecting the population.�