A grace period can help if you are little early getting a vaccine on the standard immunization schedule.

That way you don’t have to repeat a vaccine just because you got it a a few days early.
Is There a Grace Period for Getting Vaccines?
That’s right, in most cases, getting a vaccine just a little early isn’t going to mean that the vaccine dose has to be repeated.
“Doses administered too close together or at too young an age can lead to a suboptimal immune response. However, administering a dose a few days earlier than the minimum interval or age is unlikely to have a substantially negative effect on the immune response to that dose. Known as the “grace period”, vaccine doses administered ≤4 days before the minimum interval or age are considered valid; however, local or state mandates might supersede this 4-day guideline.”
General Best Practice Guidelines for Immunization: Best Practices Guidance of the Advisory Committee on Immunization Practices (ACIP)
Why not?
Aren’t there strict rules, minimum ages and intervals for getting vaccines?
There are, but the Advisory Committee on Immunization Practices (ACIP) allows a 4-day grace period for most vaccines. So if your child got their vaccines 3 or 4 days before their 1st birthday, instead of on or after turning 12 months old, they would still count!
It is important to keep in mind that:
- day one is the day before the day that marks the minimum age or minimum interval for a vaccine.
- the grace period doesn’t apply to the rabies vaccine
- if a vaccine is given five or more days too early, beyond the grace period, then the interval to the next dose starts from the day that invalid dose was given. For example, if the second dose of Hib is given two weeks after the first dose (instead of the minimum four weeks), then you don’t repeat this invalid dose in two weeks (four weeks from the first dose), but instead wait an additional four weeks from the invalid second dose
- you can’t usually add the grace period to an accelerated schedule
- live vaccines must be given at least 28 days apart if they are not given at the same time and the grace period can not be used to shorten this interval
Most importantly, in place since 2002, the grace period protects kids from having to repeat vaccines because of minor vaccine scheduling errors.
Is There a Grace Period for Getting COVID Vaccines?
And yes, the grace period also applies to getting the COVID vaccines!
At least for the second dose.
“…second doses administered within a grace period of 4 days earlier than the recommended date for the second dose are still considered valid.”
Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Authorized in the United States
Technically, while there isn’t a grace period for getting the first COVID vaccine dose early, but that dose might still count.
“If age 12 to 17 years and a vaccine other than Pfizer-BioNTech was inadvertently administered; If Moderna vaccine administered as the first dose, may administer Moderna vaccine as the second dose (as off-label use, because Moderna vaccine is not authorized in this age group).”
Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Authorized in the United States
What about if the first dose was given early?
The CDC hasn’t officially commented on this yet, but you would figure this dose would count.
“No, the grace period cannot be used to schedule second doses. Administer doses as close to the 28-day interval as possible, but not earlier than recommended. The grace period should be used only for retrospectively reviewing records. If it is discovered a dose has been inadvertently administered within a grace period of ≤4 days from the recommended date for the second dose (i.e., 24–27 days after dose 1), the dose is considered valid.”
Moderna COVID-19 Vaccine Questions
Remember though that the grace period is to help with vaccine administration errors. You are not supposed to use the grace period to accommodate a person’s schedule.
More on the Vaccine Grace Periods
- Vaccine Schedules from the 1940s to 2019
- Why Are Vaccine Schedules Different in Each Country?
- What Is the Evidence for Alternative Vaccine Schedules?
- How is the Immunization Schedule Developed?
- Catch-Up Immunization Schedules
- General Best Practice Guidelines for Immunization: Best Practices Guidance of the Advisory Committee on Immunization Practices (ACIP)
- CDC – Your Child’s Vaccine Visit
- CDC – The Vaccination Records: Finding, Interpreting, and Recording
- CDC – Recommended and Minimum Ages and Intervals Between Doses of Routinely Recommended Vaccines
- IAC – Ask the Experts about Scheduling Vaccines
- CDC – General Principles for Vaccine Scheduling
- CDC – Catch-Up Immunization Schedule for Persons Aged 4 Months Through 18 Years Who Start Late or Who Are More Than 1 Month Behind
- CDC – Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Authorized in the United States
- CDC – Moderna COVID-19 Vaccine Questions
- IAC – Ask the Experts about COVID Vaccines
- Minimum Ages and Minimum Intervals Between Doses of Vaccines in a Series – Why Does It Matter?
- WHO – Table 3: Recommendations* for Interrupted or Delayed Routine Immunization – Summary of WHO Position Papers
- Study – Impact of the Advisory Committee on Immunization Practices’ 4-day grace period in a low-income community.