An 8-week interval between the first and second doses of the Pfizer-BioNTech and Moderna COVID-19 vaccines may be considered for some individuals 12 years of age and older, especially for males 12 to 39 years of age, according to the Centers for Disease Control and Prevention (CDC).

The CDC added the consideration to extend the dosing interval to potentially reduce the risk for myocarditis in certain populations. While the absolute risk is small, the relative risk for myocarditis was found to be higher in males between 12 and 39 years of age.

Studies in adolescents between 12 to 17 years of age and adults have shown that an extended primary series interval may reduce the small risk of myocarditis associated with mRNA COVID-19 vaccines and improve immunogenicity and vaccine effectiveness. No additional benefit has been observed with extending the interval beyond 8 weeks. Data are currently unavailable for children 11 years of age and younger

A 3-week and 4-week dosing interval for the Pfizer-BioNTech and Moderna COVID-19 vaccine, respectively, is still recommended for individuals who are moderately to severely immunocompromised, 65 years of age and older, and those who need rapid protection due to increased concern about community transmission or risk of severe disease. 

The Pfizer-BioNTech COVID-19 vaccine is authorized for use in individuals 5 years of age and older and is approved in those 16 years of age and older. The Moderna COVID-19 vaccine is approved for individuals 18 years of age and older.


Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States. News release. Centers for Disease Control and Prevention. Updated February 22, 2022. Accessed February 24, 2022.