139th Confirmation of Polio Remains a Global Risk

In the United States, most people say that polio has been eradicated for many years. While this assumption may be accurate for U.S. residents, international travelers should have a different perspective.

For the 139th time, the WHO Director-General convened the Emergency Committee under the International Health Regulations (2005) (IHR) on the international spread of poliovirus.

During this July 2024 meeting, the Emergency Committee reviewed the data on wild poliovirus (WPV1) and circulating vaccine-derived polioviruses (cVDPV) in the context of the global targets of interruption and certification of WPV1 eradication by 2026 and interruption and certification of cVDPV2 elimination by 2028.

The Committee unanimously agreed that the risk of the international spread of poliovirus remains a Public Health Emergency of International Concern (PHEIC) and recommended extending Temporary Recommendations for another three months. 

Effective on August 12, 2024, the Director-General endorsed the Committee’s recommendations for countries meeting the definition for ‘States infected with WPV1, cVDPV1 or cVDPV3 with potential risk for international spread’, ‘States infected with cVDPV2 with potential risk for international spread’ and for ‘States previously infected by WPV1 or cVDPV within the last 24 months’ and extended the Temporary Recommendations under the IHR to reduce the risk of the international spread of poliovirus.

Furthermore, the WHO wrote that all countries should ensure that residents and long­term visitors of all ages receive bivalent oral or inactivated poliovirus vaccines (IPV) between four weeks and 12 months before international travel.

Ensure that those undertaking urgent travel (within four weeks) who have not received a dose of bOPV or inactivated poliovirus vaccine (IPV) in the previous four weeks to 12 months receive a dose of polio vaccine at least by the time of departure, as this will still provide benefit, particularly for frequent travelers.

An oral vaccine can reduce polio outbreaks, while the injected IPV prevents paralysis, but it does not stop the spreading of the virus. 

The fecal-oral route most often spreads the virus, and less than 1% of wild poliovirus infections result in paralysis.

At the point of departure, the international travel of any resident lacking documentation of appropriate polio vaccination from all points of departure, irrespective of the means of road, air, or sea travel, should be restricted.

Following the recent WHO announcement, the U.S. CDC reissued its Level 2—Practice Enhanced Precautions, Travel Health Advisory, which listed 37 countries with poliovirus detections in the past year.

On August 20, 2024, the CDC confirmed polio can be prevented with appropriate vaccinations before visiting endemic countries. Before traveling to any destination listed, adults who previously completed the routine polio vaccine series may receive a single, lifetime booster dose of the polio vaccine.

The IPV has been offered in the U.S. since 2000 and continues to be available at travel clinics and pharmacies in 2024.

Internationally, the novel oral polio vaccine (nOPV2) is being used to stop transmission of cVDPV2, currently the most prevalent form of the variant poliovirus.