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

  • No circulating vaccine-derived poliovirus type 2 (cVDPV2) was reported in the past week.
  • In the Lake Chad region, cVDPV2 linked to the outbreak originating in Nigeria has been detected in Niger (one case in 2019 and ten cases in 2018), and Cameroon (one positive environmental sample, collected on 20 April 2019 in Extreme Nord.
  • The risk of further cVDPV2 spread across the Lake Chad subregion remains high.

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 May 2019.

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