Africa Declared Free of Wild-Type Poliovirus — Vaccine-Derived Virus Persists

By Joe Elia

Edited by David G. Fairchild, MD, MPH, and Lorenzo Di Francesco, MD, FACP, FHM

Wild-type poliovirus — the variety found outside of vaccines — has been eliminated from the African continent, the Africa Regional Certification Commission declared on Tuesday.

Vaccine-derived poliovirus, however, infected 320 people on the continent last year, according to the New York Times. That is in contrast to the situation some 25 years ago, when wild-type polio paralyzed roughly 75,000 African children annually.

Vaccine-derived infections are occurring mainly in areas where there has been only partial vaccination. Efforts in those areas, in particular Nigeria, have been hampered by misinformation about the vaccine's safety and by violent insurgencies. The disease caused by the mutated form of the vaccine's virus causes paralysis in about one case per 200.

Wild-type infections are still reported in Afghanistan and Pakistan.