Circulating vaccine derived polio virus type 1 outbreak, Saadah governorate, Yemen, 2020.

The new emerging VDPV1 was retrospectively confirmed after one year of sample collection from Sahar district. Delayed lab confirmation, as well as the response and low immunization profile of children against polio, were the main predisposing factors for cVDPV1 outbreak. This outbreak highlights the need to maintain regular biweekly shipments to referral polio labs in the short-term, and the exploration of other options in the longer-term to enable the Yemen National Lab to fully process national samples itself.