Population immunity against Serotype-2 Poliomyelitis leading up to the global withdrawal of the oral Poliovirus Vaccine: Spatio-temporal modelling of surveillance data
Global withdrawal of serotype-2 oral poliovirus vaccine (OPV2) took place in April 2016. This marked a milestone in global polio eradication and was a public health intervention of unprecedented scale, affecting 155 countries. Achieving high levels of serotype-2 population immunity before OPV2 withdrawal was critical to avoid subsequent outbreaks of serotype-2 vaccine-derived polioviruses (VDPV2s).