Monitoring and Validation of the Global Replacement of tOPV with bOPV, April-May 2016.

The phased withdrawal of oral polio vaccine (OPV) associated with the Polio Eradication and Endgame Strategic Plan 2013-2018 began with the synchronized global replacement of trivalent OPV (tOPV) with bivalent OPV (bOPV) during April - May 2016, a transition referred to as the "switch." The World Health Organization's (WHO) Strategic Advisory Group of Experts (SAGE) on Immunization recommended conducting this synchronized switch in all 155 OPV-using countries and territories (which collectively administered several hundred million doses of tOPV each year via several hundred thousand facilities) to reduce risks of re-emergence of vaccine-derived polioviruses. Safe execution of this switch required implementation of an associated independent monitoring strategy, the primary objective of which was verification that tOPV was no longer available for administration post-switch. This strategy had to be both practical and rigorous such that tOPV withdrawal could be reasonably employed and confirmed in all countries and territories within a discreet timeframe. Following these principles, WHO recommended that designated monitors in each of the 155 countries and territories visit all vaccine stores as well as a 10% sample of highest-risk health facilities within two weeks of the national switch date, removing any tOPV vials found. National governments were required to provide the WHO with formal validation of execution and monitoring of the switch. In practice, all countries reported cessation of tOPV by 12 May 2016 and 95% of countries and territories submitted detailed monitoring data to WHO. According to these data, 272 out of 276 (99%) national stores, 3,741 out of 3.968 (94%) regional stores, 16,144 out of 22,372 (72%) district level stores, and 143,050 out of 595,401 (24%) of health facilities were monitored. These data, along with field reports suggest that monitoring and validation of the switch was efficient and effective, and that the strategies used during the process could be adapted to future stages of OPV withdrawal.

Managing the Planned Cessation of a Global Supply Market: Lessons Learned From the Global Cessation of the Trivalent Oral Poliovirus Vaccine Market.

The Polio Eradication and Endgame Strategic Plan 2013-2018 calls for the phased withdrawal of OPV, beginning with the globally synchronized cessation of tOPV by mid 2016. From a global vaccine supply management perspective, the strategy provided two key challenges; (1) the planned cessation of a high volume vaccine market; and (2) the uncertainty of demand leading and timeline as total vaccine requirements were contingent on epidemiology. The withdrawal of trivalent OPV provided a number of useful lessons that could be applied for the final OPV cessation. If carefully planned for and based on a close collaboration between programme partners and manufacturers, the cessation of a supply market can be undertaken with a successful outcome for both parties. As financial risks to manufacturers increase even further with OPV cessation, early engagement from the cessation planning phase and consideration of production lead times will be critical to ensure sufficient supply throughout to achieve programmatic objectives. As the GPEI will need to rely on residual stocks including with manufacturers through to the last campaign to achieve its objectives, the GPEI should consider to decide on and communicate a suitable mechanism for co-sharing of financial risks or other financial arrangement for the outer years.

Intradermal Administration of Fractional Doses of Inactivated Poliovirus Vaccine: A Dose-Sparing Option for Polio Immunization.

A fractional dose of inactivated poliovirus vaccine (fIPV) administered by the intradermal route delivers one fifth of the full vaccine dose administered by the intramuscular route and offers a potential dose-sparing strategy to stretch the limited global IPV supply while further improving population immunity. Multiple studies have assessed immunogenicity of intradermal fIPV compared with the full intramuscular dose and demonstrated encouraging results. Novel intradermal devices, including intradermal adapters and disposable-syringe jet injectors, have also been developed and evaluated as alternatives to traditional Bacillus Calmette-Guérin needles and syringes for the administration of fIPV. Initial experience in India, Pakistan, and Sri Lanka suggests that it is operationally feasible to implement fIPV vaccination on a large scale. Given the available scientific data and operational feasibility shown in early-adopter countries, countries are encouraged to consider introducing a fIPV strategy into their routine immunization and supplementary immunization activities.

Lessons Learned From Managing the Planning and Implementation of Inactivated Polio Vaccine Introduction in Support of the Polio Endgame.

The Immunization Systems Management Group (IMG) was established as a time-limited entity, responsible for the management and coordination of Objective 2 of the Polio Eradication and Endgame Strategic Plan. This objective called for the introduction of at least 1 dose of inactivated polio vaccine (IPV) into the routine immunization programs of all countries using oral polio vaccine (OPV) only. Despite global vaccine shortages, which limited countries' abilities to access IPV in a timely manner, 105 of 126 countries using OPV only introduced IPV within a 2.5-year period, making it the fastest rollout of a new vaccine in history. This achievement can be attributed to several factors, including the coordination work of the IMG; high-level engagement and advocacy across partners; the strong foundations of the Expanded Programme on Immunization at all levels; Gavi, the Vaccine Alliance's vaccine introduction experiences and mechanisms; innovative approaches; and proactive communications. In many ways, the IMG's work on IPV introduction can serve as a model for other vaccine introductions, especially in an accelerated context.