Polio endgame: the global introduction of inactivated polio vaccine

Abstract

In 2013, the World Health Assembly endorsed a plan that calls for the ultimate withdrawal of oral polio vaccines (OPV) from all immunization programs globally. The withdrawal would begin in a phased manner with removal of the type 2 component of OPV in 2016 through a global switch from trivalent OPV to bivalent OPV (containing only types 1 and 3). To mitigate risks associated with immunity gaps after OPV type 2 withdrawal, the WHO Strategic Advisory Group of Experts has recommended that all 126 OPV-only using countries introduce at least one dose of inactivated polio vaccine into routine immunization programs by end-2015, before the trivalent OPV-bivalent OPV switch. The introduction of inactivated polio vaccine would reduce risks of reintroduction of type 2 poliovirus by providing some level of seroprotection, facilitating interruption of transmission if outbreaks occur, and accelerating eradication by boosting immunity to types 1 and 3 polioviruses.

Keywords:

• eradication
• immunization
• inactivated polio vaccine
• oral polio vaccine
• polio
• poliomyelitis

Disclaimer

The contents of this manuscript are solely the responsibility of the authors and do not necessarily represent the official views of any specific organization.

Financial & competing interests disclosure

W Orenstein and J Garon are supported by the Bill and Melinda Gates Foundation under Work Order 23848, and M Patel is supported by Grant OPP1095024. Apart from those disclosed, the authors do not have any conflicts of interest to report and do not have relevant affiliations, relationships, or financial involvement with organizations with a financial interest in materials disclosed in the manuscript.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Because oral polio vaccine (OPV) can, in extremely rare cases, cause paralysis, OPV withdrawal must occur, in addition to wild poliovirus eradication, for the world to be polio free.

• The WHO Strategic Advisory Group of Experts has recommended that prior to the OPV withdrawal, all OPV-only using countries:

  • – Introduce at least one dose of inactivated polio vaccine (IPV) into their routine immunization program before the end of 2015; and that this dose be administered at or after 14 weeks of age at the time of the DTP3/penta3 contact in addition to the third dose of OPV, and

• OPV cessation will occur globally in two phases, first with the removal of the type 2 component in 2016 (global switch from trivalent OPV to bivalent OPV, containing types 1 and 3) setting the stage for eventually ending bivalent OPV use in 2019–2020 after certification that WPV1 and WPV3 circulation have been eradicated.

• Introducing IPV before the trivalent OPV-bivalent OPV switch in 2016 will ensure that a substantial proportion of the population is protected against type 2 polio after the withdrawal of type 2 OPV, and help mitigate risks of potential type 2 reintroduction.

• IPV does not replace any OPV doses and should be given in addition to the OPV doses in the routine EPI schedule.

• While many of the operational aspects of introducing IPV will be similar to those for other injectable new vaccines (e.g., pneumococcal), some unique aspects to IPV introduction include: the rationale for use of IPV, the schedule and number of doses of IPV, the presentation of IPV, and, in addition, for some countries, of a third injection in a single immunization visit.

• GAVI-eligible and GAVI-graduating countries are qualified to receive support for IPV introduction on the basis of a one-dose schedule.

Notes

OPV: Oral polio vaccine.

bOPV: Bivalent oral polio vaccine; OPV: Oral polio vaccine.