Complexity of options related to restarting oral poliovirus vaccine (OPV) in national immunization programs after OPV cessation

Dominika A Kalkowska; Steven Gf Wassilak; Eric Wiesen; Concepcion F Estivariz; Cara C Burns; Kamran Badizadegan; Kimberly M Thompson

doi:10.12688/gatesopenres.14511.1

Complexity of options related to restarting oral poliovirus vaccine (OPV) in national immunization programs after OPV cessation

Gates Open Res. 2023 Apr 17:7:55. doi: 10.12688/gatesopenres.14511.1. eCollection 2023.

Authors

Dominika A Kalkowska¹, Steven Gf Wassilak², Eric Wiesen², Concepcion F Estivariz², Cara C Burns^{2

3}, Kamran Badizadegan¹, Kimberly M Thompson¹

Affiliations

¹ Kid Risk, Inc., Orlando, FL, USA.
² Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
³ National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, USA, Atlanta, GA, USA.

Abstract

Background: The polio eradication endgame continues to increase in complexity. With polio cases caused by wild poliovirus type 1 and circulating vaccine-derived polioviruses of all three types (1, 2 and 3) reported in 2022, the number, formulation, and use of poliovirus vaccines poses challenges for national immunization programs and vaccine suppliers. Prior poliovirus transmission modeling of globally-coordinated type-specific cessation of oral poliovirus vaccine (OPV) assumed creation of Sabin monovalent OPV (mOPV) stockpiles for emergencies and explored the potential need to restart OPV if the world reached a specified cumulative threshold number of cases after OPV cessation. Methods: We document the actual experience of type 2 OPV (OPV2) cessation and reconsider prior modeling assumptions related to OPV restart. We develop updated decision trees of national immunization options for poliovirus vaccines considering different possibilities for OPV restart. Results: While OPV restart represented a hypothetical situation for risk management and contingency planning to support the 2013-2018 Global Polio Eradication Initiative (GPEI) Strategic Plan, the actual epidemiological experience since OPV2 cessation raises questions about what, if any, trigger(s) could lead to restarting the use of OPV2 in routine immunization and/or plans for potential future restart of type 1 and 3 OPV after their respective cessation. The emergency use listing of a genetically stabilized novel type 2 OPV (nOPV2) and continued evaluation of nOPV for types 1 and/or 3 add further complexity by increasing the combinations of possible OPV formulations for OPV restart. Conclusions: Expanding on a 2019 discussion of the logistical challenges and implications of restarting OPV, we find a complex structure of the many options and many issues related to OPV restart decisions and policies as of early 2023. We anticipate many challenges for forecasting prospective vaccine supply needs during the polio endgame due to increasing potential combinations of poliovirus vaccine choices.

Keywords: dynamic modeling; eradication; polio; vaccine.

Grants and funding

This work was supported by the Bill and Melinda Gates Foundation [INV-009333]. Centers for Disease Control and Prevention Cooperative Agreement Number NU2RGH001915 (DAK, KB, KMT). The views expressed in this manuscript are solely those of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention or Department of Health and Human Services.