Most adults residing in the United States are presumed to be protected against polio because they received routine childhood immunization and have only a small risk of exposure to poliovirus in the United States. For decades, routine polio vaccination of U.S. residents 18 years of age and older, including those working in healthcare or in healthcare-related training, was not recommended.
In June 2022, a case of paralytic polio caused by vaccine-derived poliovirus type 2 (VDPV2) was confirmed in an unvaccinated young adult from Rockland County, New York, and wastewater surveillance in the region repeatedly detected evidence of poliovirus over the following months, suggesting the presence of an unknown number of asymptomatically infected people in the community. People who are fully vaccinated with IPV are protected from polio illness but may shed virus in their feces, if exposed. This experience underscored the ongoing risk, however small, of paralytic polio among incompletely vaccinated people in the United States.
CDC’s ACIP recommended in June 2023, that all adults (18 years and older) who are known or suspected to be unvaccinated or incompletely vaccinated against polio should complete a primary 3-dose vaccination series with IPV: 2 doses of IPV administered at an interval of 4–8 weeks; and a third dose 6–12 months after the second. If an adult previously received only one or two documented doses of polio vaccine (either trivalent OPV or IPV), the person should receive the remaining dose(s) of IPV necessary to complete the series, regardless of the interval since the last dose. It is not necessary to restart the vaccination series.
Polio vaccination with a complete primary series is recommended for all travelers to countries with wild poliovirus (WPV) or vaccine-derived poliovirus (VDPV) circulation. WHO recommends that countries affected by WPV or cVDPV require long-term visitors (4 weeks or longer) to provide proof of polio vaccination before leaving the country. For additional information on countries with WPV or VDPV circulation, as well as country-specific requirements for documentation of vaccination, consult the CDC Travelers’ Health website (wwwnc.cdc.gov/travel/).
Adults who have completed a routine series of polio vaccine (with trivalent OPV or IPV in any combination) are considered to have lifelong immunity to poliomyelitis, but data on duration of immunity are lacking. In June 2023, ACIP affirmed and clarified its longstanding recommendation that certain adults at increased risk of exposure to poliovirus may receive a single lifetime adult booster dose of IPV. Adults in situations that put them at increased risk of poliovirus exposure include: travelers going to countries where polio is epidemic or endemic; laboratory and healthcare workers who handle specimens that might contain polioviruses; and, healthcare workers or other caregivers who have close contact with a person who could be infected with poliovirus.