Moderately or severely immunocompromised people age 12 or older who received an initial mRNA COVID-19 vaccine primary series should:

• receive an additional primary dose of the same mRNA COVID-19 vaccine at least 28 days after the second mRNA dose.
• receive a single mRNA COVID-19 booster dose (Pfizer or Moderna) at least 3 months after completing their third mRNA vaccine dose.

Moderately or severely immunocompromised people age 18 or older who received an initial Johnson & Johnson COVID-19 vaccine for their primary vaccination should:

• receive an additional dose of an mRNA vaccine (Pfizer or Moderna) at least 28 days after their first Johnson & Johnson dose.
• receive a single mRNA COVID-19 booster dose (Pfizer or Moderna) at least 2 months after completing their first mRNA vaccine dose.

People age 5 to 17 must receive the Pfizer vaccine as it is the only vaccine approved for this age group. For primary and booster vaccination, people should receive an age-appropriate mRNA vaccine (Pfizer or Moderna). The Johnson & Johnson vaccine is authorized for anyone age 18 and older if no other approved vaccine is available.

CDC expanded eligibility for an additional booster dose for certain individuals who may be at higher risk of severe outcomes from COVID-19. Eligible individuals age 12 or older may choose to receive a second booster dose using an age-appropriate mRNA vaccine if it has been at least 4 months after the first booster dose.

A patient’s clinical team is best positioned to determine the appropriate timing of vaccination.