Considerations for Intervals for mRNA COVID-19 Vaccine Primary Series

An 8-week interval between the first and second primary series doses of Moderna, Novavax, and Pfizer vaccines may be optimal for some people as it may reduce the small risk of myocarditis and/or pericarditis associated with these COVID-19 vaccines.

A 3- or 4-week interval continues to be the recommended interval for:

  • People who are moderately to severely immunocompromised
  • Adults ages 65 years and older
  • In situations where the fullest possible protection needs to be achieved sooner



Page last reviewed: Devember 19, 2022