In recent weeks there has been a lot of reportage in the press of polio outbreaks in the country, some of them with frightening headlines that suggest that the wild poliovirus is back. While the vaccine-derived virus is still a menace that paralyses children, it must be distinguished from the wild poliovirus which remains at zero in Nigeria. The vaccine-derived poliovirus is a product of a few factors which lead to the mutation of the attenuated poliovirus in the oral polio vaccine to a virulent form which causes paralysis. The factors include unsanitary environments
leading to contaminated food and water and suboptimal immunisation of children. This allows the virus to survive and be transmitted through unimmunised children in populations with sub-optimal immunization levels several times during which time it takes the opportunity to mutate. Without these frequent passages through these susceptible hosts, the virus which cannot live long outside the human body will perish…. Read more.