The Advisory Committee on Immunization Practices (ACIP) recently issued new recommendations on polio vaccine for adults. The ACIP decided to update its previous recommendations (from 2000) in response to a case in New York that demonstrated the United States is at risk for poliovirus importation as long as the disease has not been eliminated worldwide.1
What happened in New York? In July 2022, a case of paralytic polio was confirmed in an unvaccinated adult in Rockland County, New York, an area that has low polio vaccine coverage. Subsequent testing of wastewater systems detected poliovirus in a total of 5 New York counties (including 2 in New York City).1
The Centers for Disease Control and Prevention estimates that this region of the state probably experienced 1000 to 2000 nonparalytic, mostly asymptomatic poliovirus infections. The virus detected in wastewater in New York is genetically linked to polioviruses collected in wastewater in Israel, the United Kingdom, and Canada. No poliovirus has been detected in these wastewater systems since late 2022.1,2
Why there’s reason for concern. Routine immunization against polio has been part of the immunization schedule for infants and children since the mid-1950s. As a result, endemic polio was eliminated in the United States in 1979 and in the Western Hemisphere in 1994.
However, adult vaccination until now has been recommended only for those at risk for exposure to poliovirus by way of travel or occupation. And while most adults in the United States are immune to polio due to childhood vaccination, unvaccinated adults remain susceptible if exposed to poliovirus—as demonstrated in the New York case.
What does the ACIP now recommend? Two recommendations were adopted by the ACIP this June to address this problem2:
- Adults who are known or suspected to be unvaccinated or incompletely vaccinated against polio should complete a primary vaccination series with inactivated polio vaccine (IPV).
- Adults who have received a primary series of oral polio vaccine (OPV) or IPV in any combination and who are at increased risk for poliovirus exposure may receive another dose of IPV. Available data do not indicate a need for > 1 lifetime booster.
A few details: To be considered fully vaccinated, a patient must have received a primary series of ≥ 3 doses of OPV or IPV (in any combination) given at least 4 weeks apart, with the last dose given on or after the 4th birthday and at least 6 months from the previous dose. Most adults who were born and raised in the United States can assume they were vaccinated against polio as children, unless there are specific reasons to suspect otherwise.2
Individuals considered to be at increased risk include: travelers who are going to countries where polio is epidemic or endemic; laboratory and health care workers who handle specimens that might contain polioviruses; and health care workers or other caregivers who have close contact with a person who could be infected with poliovirus.2
Take-home message. Be prepared to discuss and offer IPV (the only form of the vaccine currently in use in the United States) to adults, as either a one-time booster for those at increased risk for exposure to poliovirus or a complete series for those you know or suspect to be unvaccinated or incompletely vaccinated.