Nigeria announced that three years have passed since it last recorded a case of polio, a key step towards eradicating the notorious disease in Africa, according to the World Health Organization (WHO).

This is a big change from 2012 when the country accounted for more than half of all polio cases worldwide. While it can be seen as a significant milestone, it will be several months before the country can officially be labeled polio-free.

Now, the WHO need to make sure there is a robust surveillance system in Nigeria to be certain that there are no further cases of the wild poliovirus, the chairman of Nigeria‘s polio committee, Dr Tunji Funsho, said.

“We are confident that very soon we will be back here trumpeting the certification that countries have, once and for all, kicked polio out of Africa,” said Dr. Matshidiso Moeti, WHO regional director for Africa.

Nigeria is the last country in Africa to have witnessed a case of polio — in Borno state, in the north-east. Outside of Nigeria, the last case on the continent was in the Puntland region of Somalia, in 2014.

Insecurity in the north-east of Nigeria had hindered the polio vaccination program, but success in fighting the Boko Haram militant group has been cited as one of the reasons behind the recent success.

In addition, officials have said that political support and an injection of funds have also helped. In 2018, there were a total of 33 polio cases confined to just two countries: Afghanistan and Pakistan.

Matshidiso Moeti said the continent is “on the verge of an extraordinary public health achievement; one which will be our legacy to our children and children’s children”. But health experts urge caution.

They must first be sure that every part of the continent has been reached and no cases have been missed. For now, there are renewed calls to vaccinate children against polio. It has taken the effort of thousands of volunteers to deliver the much-needed vaccines to all parts of the continent.

Polio, a highly infectious disease, invades the nervous system and can cause total paralysis in a matter of hours. Initial symptoms include fever, fatigue, and headache. One in 200 infections leads to irreversible paralysis. Among those paralyzed, 5% to 10% die when their breathing muscles become immobilized.