An additional dose of the Pfizer vaccine is recommended for people 5 and older who are moderately or severely immunocompromisedand completed the two-dose series. The third dose of the Pfizer vaccine should be administered at least 28 days after the second dose. An additional dose has not been authorized for immunocompromised recipients of the three-dose Pfizer vaccine for children 6 months to 4 years old.

The CDC recommends people 5 and older receive an age-appropriate, updated mRNA booster dose if at least 2 months have passed since their primary series or since their most recent booster dose. Booster shots are not available for children under 5.

See additional recommendations for people who are moderately to severely immunocompromised. Speak with a pediatrician for more information.