The 2018 cVDPV3 outbreak was part of a 2-strain polio outbreak in Somalia at that time, along with circulating vaccine-derived poliovirus type 2. Both strains emerge and paralyse children in under-immunized populations – places where not enough children have consistently had access to polio vaccines. The cVDPV2 outbreak continues to paralyse children, and environmental samples – sewage water – consistently show that virus moving through Somali communities. For the polio programme, the presence of cVDPV2 samples and the absence of cVDPV3 samples is bittersweet: it demonstrates the sensitivity of our testing, so we can be confident cVDPV3 is no longer a threat to Somali children – but it makes clear that the threat of paralytic polio still looms.
Across the Region, cVDPV2 cases are on the rise – as across much of WHO’s African Region. Wild poliovirus still stalks children across Afghanistan and Pakistan, and the movement of people across borders underscores the risk of importation across and beyond the Region.
The end of Somalia’s cVDPV3 outbreak shows what can be achieved with high-quality vaccination campaigns, on-the-ground leadership and sensitive surveillance measures.
