Polio eradication: interrupting transmission, towards a polio-free world

Abstract

The polio eradication initiative is in its final phase and new tools have been developed to ensure its completion, including monovalent type 1 and 3 oral poliovirus vaccines (OPVs) that permit a virus-specific response to endemic and imported poliovirus. After eradication, the public health benefits of routine immunization with OPV will no longer outweigh the burden of disease, either owing to paralysis caused by OPV (vaccine-associated paralytic poliomyelitis) or outbreaks caused by reversion of OPV to neuro-virulent strains (circulating vaccine-derived polioviruses), and discontinuation of OPV use will be mandatory. Prerequisites for safe OPV cessation include biocontainment of all known poliovirus and potentially infected materials; an international stockpile of monovalent OPV and a response capacity. A mechanism is required for continued surveillance of poliomyelitis after eradication has been certified, as well as national policies if countries decide to continue vaccinating using inactivated poliovirus vaccine. It is ironic that the vaccine responsible for polio eradication will itself become a threat to eradication, once polio has been eradicated.