Status: affected by circulating vaccine-derived poliovirus

Circulation of vaccine-derived poliovirus type 2 (cVDPV2) has been confirmed in Niger, related to a cVDPV2 affecting Jigawa, Nigeria. Surveillance for AFP cases is being strengthened and an outbreak response will be implemented.

The detection of cVDPVs underscores the importance of maintaining high levels of routine vaccination coverage at all levels to minimize the risk and consequences of any poliovirus circulation. A robust outbreak response is needed to rapidly stop the VDPV2 transmission. WHO will continue to evaluate the epidemiological situation and outbreak response measures being implemented.

Polio this week in Lake Chad Basin

  • Three cases of circulating vaccine-derived poliovirus type 2 (cVDPV2) are reported from Niger, genetically linked to a cVDPV2 in Katsina, Nigeria, with onset of paralysis on 31 August, 6 September and 7 September, all from Zinder province.  The total number of cVDPV2 cases in 2018 is six, all from Zinder province.  These cases are all linked to the cVDPV2 outbreak in Jigawa, Nigeria.
  • The Government of Niger has declared a national public health emergency, as per the temporary recommendations of the Emergency Committee of the International Health Regulations.
  • WHO and its partners are supporting local public health authorities in field investigations and risk assessment, and to conduct additional response measures as appropriate and necessary.  Health workers are conducting active searches for additional AFP cases; surveillance is also being strengthened by taking more environmental samples from more areas and sampling the stools of healthy people.
  • The detection of wild poliovirus type 1 (WPV1) and cVDPV2 in Nigeria continue to pose a risk to the neighbouring countries of the Lake Chad basin. Emergency outbreak response and efforts to improve surveillance continue across the basin. These include efforts to vaccinate children at markets, in internally displaced persons and refugee camps, and at international borders.

International Health Regulations

Countries affected by poliovirus transmission are subject to International Health Regulations Temporary Recommendations that request them to declare a case of polio as a national public health emergency and consideration vaccination of all international travellers, as per temporary recommendations issued as of August 2018.

Travel advice

WHO’s International Travel and Health recommends that all travellers to polio-affected areas be fully vaccinated against polio. Residents (and visitors for more than 4 weeks) from infected areas should receive an additional dose of OPV or inactivated polio vaccine (IPV) within 4 weeks to 12 months of travel.

More on vaccine-derived polioviruses