Prerequisites for OPV cessation: risk management
To minimize and manage the risks associated with stopping routine immunization with OPV, six prerequisites have been established for OPV cessation.
1. Confirmation of interruption and containment of wild poliovirus transmission
Because of the ongoing risk of poliovirus importations into polio-free areas, the interruption of wild poliovirus transmission must be confirmed in every country in the world prior to the cessation of routine polio immunization anywhere. All wild polioviruses must be placed under appropriate bio-containment levels to minimize the risk of re-introduction into a polio-free world.
2. Continued highly sensitive surveillance for and rapid notification of poliovirus circulation
Highly sensitive surveillance and efficient reporting are required before, during and after OPV cessation to confirm interruption of wild poliovirus transmission, document the elimination of Sabin strains and rapidly detect the potential reintroduction of any poliovirus.
3. Establishment of an international stockpile of monovalent oral polio vaccines (mOPV) and a global response mechanism
An international stockpile of types 1, 2 and 3 monovalent OPV is needed to allow a 'type-specific' response during the process of OPV cessation. This would enhance the impact of the outbreak response while preventing the reintroduction of other polioviruses.
4. Implementation of inactivated polio vaccine (IPV) requirements in countries that retain poliovirus for research and/or vaccine production
Any country choosing to retain poliovirus (for either research purposes or in order to produce vaccine) is expected to have a policy in place for routine IPV immunization which will ensure coverage sufficient to prevent polio transmission.
5. International consensus on the procedure for synchronous OPV cessation
All countries will need to simultaneously stop the use of OPV for routine immunization to ensure that no country is inadvertently put at risk of importing a cVDPV from a country that continues to use OPV. Following OPV cessation, documentation of the destruction of remaining trivalent OPV stocks will need to be verified in each country.
6. Appropriate bio-containment of Sabin polioviruses
Because of their ability to mutate to a virulent form and re-establish circulation and infection, Sabin polioviruses must be treated similarly to wild-type polioviruses and placed under appropriate bio-containment levels.