The Trivalent to Bivalent Oral Polio Vaccine Switch

Between 17 April and 1 May, the type 2 component of the oral polio vaccine (OPV) is being removed from use through a globally synchronized switch from the trivalent to bivalent oral polio vaccine. This is the first stage of Objective 2 of the Polio Eradication and Endgame Strategic Plan 2013-2018 to withdraw OPV in a phased manner starting with the type 2 component following the eradication of wild poliovirus type 2 in September 2015.

Thanks to the efforts of a wide range of stakeholders from Ministries of Health, health workers, volunteers, switch monitors, WHO, UNCEF and partners of the World Health Organization, confirmation has been received that 152 countries have completed the switch.


The following indicators are being carefully tracked to ensure the switch goes smoothly.   As of 10 May:

·       154 of 155 (99%) countries and territories have stopped using the trivalent oral polio vaccine.

·       Independent monitoring to ensure the switch goes smoothly has begun in 149 of 153 countries (98%).

·       The National Validation Committee has received switch monitoring data from 45 of 153 countries.

·       The WHO Regional Office has received the National Validation Report from 43 countries. 

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