The CDC has updated its Interim Clinical Considerations on the use of approved mRNA COVID-19 vaccines used in the United States to extend the dosing interval between the first and second dose of the Pfizer BioNTech and Moderna vaccines for some people, particularly males ages 12 to 39 years, to up to 8 weeks between doses.
The agency notes that a 3-week (Pfizer-BioNTech) or 4-week (Moderna) interval between the first and second dose continues to be the recommended interval for people who are moderately or severely immunocompromised, persons ages 65 years and older, and others who need rapid protection due to increased concern about community transmission.
The new recommendation concerns the small risk of myocarditis associated with mRNA COVID-19 vaccines, particularly in males ages 12 to 39 years. The risk might be reduced, and peak antibody responses and vaccine effectiveness might be increased, with a longer dosing interval—up to 8 weeks between doses, the CDC states.