The World Health Organization (WHO) has advised Nigeria and other countries in the region not to be complacent in their efforts to eradicate polio.
WHO Regional Director for Africa, Dr Matshidiso Moeti, gave the advice in her statement to commemorate this year's World Polio Day today.
She said until polio is eradicated, all countries remain at risk of outbreaks.
"If no new case is confirmed, and surveillance is quickly strengthened, the African Region can be certified to have eradicated polio by the end of 2019 or early 2020," she added.
The WHO regional boss said since the launch of the Global Polio Eradication Initiative (GPEI) nearly 30 years ago, new cases of polio have dropped by more than 99.9 percent - from 350,000 cases every year in more than 125 affected countries, to 22 wild polio cases in 2017 in two affected countries.