A single booster dose of the Pfizer COVID-19 vaccine has been authorized for limited populations who are at highest risk for COVID-19 based on their age or certain underlying medical conditions, and for those in high-risk occupational and institutional settings. The booster dose will help maximize ongoing protection against COVID-19. A booster dose can be given at least six months following completion of the primary Pfizer series.

• People 65 years and older and residents in long-term care settings should receive a booster shot.  
• People ages 50 to 64 with certain underlying medical conditions should receive a booster shot.  
• People ages 18 to 49 who are at high risk for severe COVID-19 due to certain underlying medical conditions may receive a booster shot based on their individual benefits and risks.  
• People ages 18-64 who are at increased risk for COVID-19 exposure and transmission because of occupational or institutional setting may receive a booster shot based on their individual benefits and risks.  

People in the recommended groups based on risk who received the Moderna or Johnson & Johnson vaccine may need a booster shot in the future, and more data on the effectiveness and safety of these booster shots are expected in the coming weeks. The FDA and CDC will review that data and make recommendations accordingly.

Immunocompromised individuals who meet certain, specific criteria and received an mRNA vaccine (either Pfizer or Moderna) are already eligible for a third dose in their main primary series to strengthen their initial vaccine response. This additional dose should not be confused with a booster dose, which is used to strengthen waning immunity and bolster protection against serious outcomes including hospitalization and death.

Because the Johnson & Johnson vaccine was not used in the U.S. until later, more data is needed before plans for a J&J booster will move forward, but the CDC anticipates booster shots will also be advised for those who received J&J vaccines.