Technically Speaking: Don’t Make the Mistake of Scheduling Dose Two of COVID-19 Vaccine Too Early
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Vaccine Update for Healthcare ProvidersThere have been numerous reports of mRNA COVID-19 vaccine recipients being asked to return earlier than the recommended interval to receive their second dose. Frequently, this has been caused by a misunderstanding about the intent of allowing a 4-day grace period when determining the interval between dose one and dose two.
When the clinical considerations for COVID-19 vaccines were first published by CDC, they included the concept that a “grace period” of 4 days was allowable if the minimum interval between doses was inadvertently shortened. A similar grace period has been in place for other vaccines for many years. However, the grace period was intended to be used only when a vaccine was determined retroactively to have been given at less than the recommended minimum interval. In that case, a dose given within 4 days of the recommended interval would not have to be repeated. The grace period was not intended to be used when scheduling future vaccination visits.
For COVID-19 vaccines currently available in the U.S., the recommended interval that should be used for scheduling between dose one and dose two is:
- Pfizer-BioNTech — 21 days
- Moderna — 28 days
On Jan. 6, 2021, CDC revised its Interim Clinical Considerations for Use of mRNA COVID-19 Vaccines Currently Authorized in the United States to emphasize the necessity of vaccinating according to the recommended schedule. The information regarding dosing intervals is summarized below:
- Routine Scheduling. Do not schedule people to receive dose two earlier than the recommended intervals (i.e., 21 days for Pfizer-BioNTech or 28 days for Moderna).
- Inadvertent Early Doses. If dose two is inadvertently administered as much as 4 days too early (“grace period”), it may be considered valid, but this 4-day period should not be utilized for routine scheduling.
- No Maximum Interval. There is no maximum interval between dose one and dose two for either vaccine. If dose two is administered beyond 21 (Pfizer-BioNTech) or 28 days (Moderna), there is no need to restart the series.
Visit CDC's Interim Clinical Considerations for Use of mRNA COVID-19 Vaccines Currently Authorized in the United States for full details.
Related Links
- CDC's Pfizer-BioNTech COVID-19 Vaccine webpage
- CDC's Moderna COVID-19 Vaccine webpage
- Pfizer-BioNTech COVID-19 Vaccine Standing Orders for Administering Vaccine to Persons 16 Years of Age and Older
- Moderna COVID-19 Vaccine Standing Orders for Administering Vaccine to Persons 18 Years of Age and Older
- IAC’s Vaccines: COVID-19 webpage
- IAC’s Ask the Experts: COVID-19 webpage
- IAC’s COVID-19 mRNA Vaccines — What Clinic Personnel Need to Know – A side-by-side comparison table of the two mRNA vaccines
Contributed by: Deborah Wexler, MD
Categories: Vaccine Update January 2021, Technically Speaking
Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.
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