Vaccine-derived poliovirus in Congo, Burundi

Johannesburg [South Africa], March 19: Health officials in Burundi and the Democratic Republic of Congo have detected cases of vaccine-derived poliovirus, the World Health Organization and Global Polio Eradication Initiative said.The WHO said the Burundian government had declared the detection of the virus a national public health emergency after cases were confirmed in an unvaccinated four-year-old boy in the Isale district in western Burundi and two other children who were his contacts. Five other samples from environmental surveillance of wastewater confirmed circulating poliovirus type 2 in Burundi, the WHO added in a statement.
Circulating poliovirus type 2 is different to wild poliovirus, with infections occurring when a weakened strain of poliovirus contained in the oral polio vaccine circulates among under-immunized populations for long periods. The detections are significant as they are the first linked with the use of a new vaccine, the novel oral poliomyelitis vaccine type 2 (nOPV2), which was developed specifically to reduce this risk.
Source: Qatar Tribune