The schedule for polio vaccination for unvaccinated or under-vaccinated older children and adults is 2 doses of IPV separated by 4–8 weeks, and a third dose 6–12 months after the second dose (the final dose must be given after the fourth birthday). If an accelerated schedule is needed, the first two doses should be separated by at least 4 weeks and the third (final) dose given at least 6 months after the second dose. In June 2023, the CDC’s Advisory Committee on Immunization Practices (ACIP) recommended that any adult known or suspected to be unvaccinated or incompletely vaccinated should complete a primary IPV series.