Scheduling 2-Dose Primary Series

Scheduling doses

*You may administer COVID-19 vaccines and other vaccines at the same visit.

#All doses of the primary series should be completed with the same product. In exceptional situations in which the vaccine product given for the first dose vaccine product cannot be determined or is no longer available, any available mRNA COVID-19 vaccine may be administered at least 28 days after the first dose.

**Administer the second dose as close to the recommended interval (21 days) as possible. If the second dose is administered after this interval, the series does not need to be restarted. Primary series doses inadvertently administered before the 4-day grace period (i.e., less than 17 days apart) should be repeated.



COMIRNATY and Pfizer-BioNTech COVID-19 Vaccine

The Advisory Committee on Immunization Practices’ Interim Recommendation for Use of Pfizer-BioNTech COVID-19 Vaccine — United States, December 2020



Page last reviewed: November 16, 2021