Closing the surveillance gap: strengthening environmental and clinical poliovirus detection in Somalia's conflict-affected zones

Somalia has not detected wild poliovirus since 2014, yet persistent transmission of circulating vaccine-derived poliovirus type 2 (cVDPV2) since 2017—with 39 confirmed cases across 14 regions as of March 2024 and international spread to Ethiopia and Kenya—underscores a critical ''surveillance-to-action gap.'' Detection through acute flaccid paralysis and environmental surveillance does not reliably translate into effective response. In conflict-affected zones, an estimated 500,000 children under five remain unreachable for vaccination, with 95% of zero-dose children from the South Central region and 60% residing in inaccessible districts. Novel diagnostic tools, including a multiplex poliovirus type 2-specific real-time quantitative PCR assay with 98.3% specificity, enable rapid detection of cVDPV2 RNA in wastewater and stool samples, potentially transforming environmental surveillance into a real-time early warning system. However, laboratory advances must be complemented by community engagement; programs have successfully traced and vaccinated over 39,000 zero dose and defaulter children through local leadership networks. Somalia's polio strategy must evolve from passive detection to an integrated surveillance-for-action system. Priorities include deploying rapid molecular diagnostics, linking detections to district level micro plans targeting zero-dose children, expanding community-based surveillance to inaccessible areas, and strengthening cross-border coordination. Without this decisive shift, cVDPV2 will continue to circulate silently among vulnerable children and threaten regional eradication gains.