Information on Delayed Second Doses
Across our region and the nation, weather challenges are forcing some people to delay getting their second dose due to vaccine supply. While getting the second dose as close to the recommended interval as possible, if delay is unavoidable, the second dose may be administered up to 6 weeks after the first dose. The following information from the Centers for Disease Control (CDC) can help provide more details and clarify questions.
The mRNA COVID-19 vaccine series consist of two doses administered intramuscularly:
- Pfizer-BioNTech (30 µg, 0.3 ml each): 3 weeks (21 days) apart
- Moderna (100 µg, 0.5 ml): 1 month (28 days) apart
Persons should not be scheduled to receive the second dose earlier than recommended (i.e., 3 weeks [Pfizer-BioNTech] or 1 month [Moderna]). However, second doses administered within a grace period of 4 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 and a delay in vaccination is unavoidable, the second dose of Pfizer-BioNTech and Moderna COVID-19 vaccines may be administered up to 6 weeks (42 days) after the first dose. There are currently limited data on efficacy of mRNA COVID-19 vaccines administered beyond this window. If the second dose is administered beyond these intervals, there is no need to restart the series.