CDC Updates Information on Vaccinations

Situation Report | January 25, 2021

The U.S. Centers for Disease Control and Prevention (CDC) has updated its information on vaccinations, including recommendations on intervals between the first and second dose. 

The COVID-19 vaccine series consist of two doses administered intramuscularly: 

  • Pfizer-BioNTech – 3 weeks (21 days) apart
  • Moderna – 1 month (28 days) apart

Persons should not be scheduled to receive the second dose earlier than recommended; however, second doses administered within a grace period of four days earlier than the recommended date for the second dose are still considered valid. Doses inadvertently administered earlier than the grace period should not be repeated.

The second dose should be administered as close to the recommended interval as possible. However, if it is not feasible to adhere to the recommended interval, the second dose of Pfizer-BioNTech and Moderna COVID-19 vaccines may be scheduled for administration up to six weeks (42 days) after the first dose. There is currently limited data on efficacy of COVID-19 vaccines administered beyond this window. If the second dose is administered beyond these intervals, there is no need to restart the series.