Africa declared free of wild polio

Africa has been declared free from wild polio by the independent body, the Africa Regional Certification Commission.
A region is certified as free of wild polio after three years have passed without the virus being detected in any of its countries.
- Nigeria is the last African country to be declared free from wild polio.
Wild polio is still present in Pakistan and Afghanistan.
It is a strain of the weakened poliovirus that was initially included in oral polio vaccine (OPV) and that has changed over time and behaves more like the wild or naturally occurring virus.
Oral polio vaccine (OPV) contains an attenuated (weakened) vaccine-virus, activating an immune response in the body. When a child is immunized with OPV, the weakened vaccine-virus replicates in the intestine for a limited period, thereby developing immunity by building up antibodies.