Status: no longer affected by circulating vaccine-derived poliovirus 2 (cVDPV2) but remains vulnerable to re-infection

Sudan is affected by a circulating vaccine-derived poliovirus type 2 (cVDPV2). Genetically-linked VDPV2 were isolated from two AFP cases, with onset of paralysis on 7 March and 1 April from South Darfur state (in the west of the country, close to the border with Chad), and Elgedarif state in the east (close to the border with Eritrea and Ethiopia.

Though final genetic sequencing is pending for other isolates, initial investigation indicates these isolates are linked to cVDPV2s from the CHA-NDJ-1 emergence group which is currently circulating in Chad.  Additionally, three cVDPV2-positive environmental samples from Khartoum were detected – full sequencing of these isolates is pending to assess their genetic-linkage.

WHO advice

It is important that all countries, in particular those with frequent travel and contacts with polio-affected countries and areas, strengthen surveillance for AFP cases in order to rapidly detect any new virus importation and to facilitate a rapid response. Countries, territories and areas should also maintain uniformly high routine immunization coverage at the district level to minimize the consequences of any new virus introduction.

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.