4-Day Grace Period

Doses administered up to 4 days before the minimum interval, known as the 4-day grace period, are considered valid.

If a dose is administered prior to the 4-day grace period, repeat dose after the dose given in error by at least the minimum recommended interval.

Doses administered at any time after the recommended interval are valid.

Reference: Interim Clinical Considerations for Use of COVID-19 Vaccines: Appendices, References, and Previous Updates (cdc.gov)