On January 4, 2022, the U.S. Centers for Disease Control and Prevention updated booster vaccination recommendations for those who received the Pfizer vaccine from 6 months to 5 months. In addition, the CDC is also recommending that moderately or severely immunocompromised 5-11-year-olds receive an additional primary dose of vaccine 28 days after their second shot.

View the full announcement from the CDC here: https://www.cdc.gov/media/releases/2022/s0104-Pfizer-Booster.html