From eradicating wild poliovirus to eradicating vaccine-derived polioviruses: why oral polio vaccine use must now be ended.

Wild poliovirus (WPV)2 was eradicated globally in 1999, and WPV3 was eradicated in 2012. Since 2016, endemic transmission of WPV1 has remained restricted to Afghanistan and Pakistan. Circulating vaccine-derived polioviruses (cVDPVs) have become the leading cause of poliovirus transmission and paralytic disease globally. As cVDPVs originate from oral poliovirus vaccine (OPV) strains, the polio endgame must address both cVDPV outbreaks and the mechanism that generates them. We propose defining cVDPV eradication as sustained zero disease, zero transmission, and zero emergence of new cVDPV lineages. Continued OPV use exposes children, predominantly in low- and middle-income countries, to avoidable risks of vaccine-associated paralysis and cVDPV outbreaks. Accelerated transition to inactivated poliovirus vaccine-only schedules and cessation of OPV use are essential for a sustainable and equitable polio endgame.