Yemen is affected by a circulating vaccine-derived poliovirus type 1 (cVDPV1). The isolates have 17-24 Nt changes from Sabin 1, suggesting circulation of potentially up to two years.
Cases have been reported from different districts of Saada Governorate, in the north-west of the country, and outbreak response is being implemented.
With large-scale population movements with other areas of the Horn of Africa, notably Djibouti and northern Somalia, a more thorough Horn of Africa risk assessment to both type 1 and type 2 poliovirus is being conducted.
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.
International Health Regulations
Yemen is classified by the International Health Regulations (IHR) as a state infected with cVDPV2, with potential risk of international spread. It is therefore subject to temporary recommendations as of June 2020.
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.