Immunocompromised patients age 6 months or older are recommended to receive an age-appropriate 3-dose primary series of mRNA vaccine. Both Moderna and Pfizer-BioNTech products have different doses beginning at age 12 years. What dose do I do for a patient that starts the series at age 11 years but turns 12 before completing the 3-dose primary series?

CDC states (www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#timing-spacing-interchangeability) that if a person moves to an older age group between vaccine doses, they should receive the vaccine product and dosage for the older age group for all subsequent doses. Thus, CDC’s general recommendation in this case is to complete the primary series with the dose appropriate for a child age 12 years.

In the case of immunocompromised children who initiate the primary series before turning 12 years old and need to complete the primary series after turning 12, the FDA EUA also permits completing the entire 3-dose series with the formula authorized for children ages 5 through 11 years.