Coordinated global cessation of oral poliovirus vaccine use: Options and potential consequences

Abstract

Due to the very low, but nonzero, paralysis risks associated with the use of oral poliovirus vaccine (OPV), eradicating poliomyelitis requires ending all OPV use globally. The Global Polio Eradication Initiative (GPEI) coordinated cessation of Sabin type 2 OPV (OPV2 cessation) in 2016, except for emergency outbreak response. However, as of early 2023, plans for cessation of bivalent OPV (bOPV, containing types 1 and 3 OPV) remain undefined, and OPV2 use for outbreak response continues due to ongoing transmission of type 2 polioviruses and reported type 2 cases. Recent development and use of a genetically stabilized novel type 2 OPV (nOPV2) leads to additional potential vaccine options and increasing complexity in strategies for the polio endgame. Prior applications of integrated global risk, economic, and poliovirus transmission modeling consistent with GPEI strategic plans that preceded OPV2 cessation explored OPV cessation dynamics and the evaluation of options to support globally coordinated risk management efforts. The 2022-2026 GPEI strategic plan highlighted the need for early bOPV cessation planning. We review the published modeling and explore bOPV cessation immunization options as of 2022, assuming that the GPEI partners will not support restart of the use of any OPV type in routine immunization after a globally coordinated cessation of such use. We model the potential consequences of globally coordinating bOPV cessation in 2027, as anticipated in the 2022-2026 GPEI strategic plan. We do not find any options for bOPV cessation likely to succeed without a strategy of bOPV intensification to increase population immunity prior to cessation.

Keywords: dynamic modeling; eradication; oral poliovirus vaccine; polio.

Figure 1.

Expected global number of polio cases by year for 100 stochastic iterations of bOPV cessation under the 2022–2026 Strategy (on May 1, 2027) with mOPV (solid line), a best nOPV (dashed line) or a worst nOPV (dotted-dashed line) as the vaccine used for outbreak response.

Figure 2.

Vaccine options for OPV+IPV in their national immunization programs in 2022: Continued OPV cessation (current status quo shown in bold)

Figure 3.

Vaccine options for OPV+IPV in their national immunization programs in 2022: Abandoned OPV cessation without OPV2 restart in RI (current status quo shown in bold)