Publish Date: September 2016
In April 2016, the largest and fastest globally-coordinated project in the history of immunization was carried out in 155 countries and territories. Known as “the switch,” this activity entailed replacing trivalent oral polio vaccine (tOPV), which protects against all three strains of the poliovirus, with the bivalent form (bOPV) which protects against two strains, types 1 and 3. The last case of polio due to type 2 wild virus was detected in 1999, and the virus was declared eradicated in 2015. This switch, synchronized with the introduction of inactivated polio vaccine (IPV), will help to achieve the aim of global eradication of polio while eliminating the risk of vaccine-associated paralytic polio and circulating vaccine-derived polio virus due to type 2 virus.
To systematically document MCSP’s contribution to the switch and IPV introduction, a survey was sent to MCSP field staff in the 11 countries where MCSP supported the process. These countries were: Haiti, Kenya, Liberia, Madagascar, Malawi, Mozambique, Nigeria, Pakistan, Tanzania, Uganda, and Zimbabwe. This report summarizes the findings from the survey including the national and international agencies involved, the role of MCSP in the switch, challenges and successes of the switch, IPV supply/distribution problems, and tOPV supply/distribution problems. Individual country-specific sheets have been developed and are available to read about the switch for a specific MCSP-supported country.