The final dose of the standard four-dose vaccination series with inactivated poliovirus should be administered at 4 years of age or older after a minimum interval of 6 months after the third dose, according to updated recommendations from the Advisory Committee on Immunization Practices.
In addition, the committee advises using the minimum age of 6 weeks for the first dose and the minimum interval of 4 weeks between the following two doses “only if the vaccine recipient is at risk for imminent exposure to circulating poliovirus.”
This condensed vaccination schedule is not advisable in other situations because shorter intervals and an earlier start date lead to lower seroconversion rates. The normal four-dose schedule for inactivated poliovirus vaccine (IPV) sets doses at ages 2 months, 4 months, 6-18 months, and 4-6 years (MMWR 2009;58:829-30).
ACIP also clarified the poliovirus vaccination schedule that should be used with the combination vaccine DTaP-IPV/Hib (Pentacel). When four doses of DTaP-IPV/Hib are administered at ages 2, 4, 6, and 15-18 months, ACIP recommends using an additional fifth booster dose of IPV (Ipol) or DTaP-IPV (Kinrix) at age 4-6 years, with a minimum interval of at least 6 months between the fourth and fifth dose.