Abbreviations: AFP, acute flaccid paralysis; bOPV, bivalent 1+3 OPV; cVDPV2, circulating vaccine-derived polio virus type 2; GPEI, Global Polio Eradication Initiative; IPV, inactivated polio vaccine; mOPV2, monovalent OPV type 2; OPV, trivalent oral polio vaccine; VDPV, vaccine-derived polio virus; WHA, World Health Assembly; WPV, wild polio virus