Use of mOPV1 in Routine Immunization in Pakistan.

Pakistan has uninterrupted circulation of polioviruses and this may threaten the entire global community. Bivalent OPV (bOPV), which protects against types 1 and 3, is used for routine immunization. However, type-3 wild poliovirus is on the verge of eradication, therefore mOPV1 is important to achieve eradication of type-1 poliovirus. The main rationale of the study is to interrupt WPV1 circulation and stopping the outbreaks of VDPVs with the help of mOPV1 instead of bOPV2 for routine immunization, which contains live poliovirus, and will eventually lead to complete eradication and containment of type 1 WPV, vaccine-related (VDPV) and Sabin polioviruses. This study will provide data to National Immunization Authorities in order to make strategic decisions about their polio vaccination schedules in anticipation of the potential global bOPV2 to mOPV1 switch and will provide data on the proposed responses to type 1 poliovirus outbreaks.