There 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 #1 and dose #2. 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 which should be used for scheduling between dose #1 and
dose #2 is:
- Pfizer-BioNTech – 21 days
- Moderna 28 days
On January 6, 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 #2
earlier than the recommended intervals (i.e., 21 days for Pfizer-BioNTech
or 28 days for Moderna).
-
Inadvertent Early Doses. If dose #2 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 #1
and dose #2 for either vaccine. If dose #2 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
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This page was updated on
January 22, 2021. |
This page was reviewed on
January 22, 2021. |
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