In December 2020 the FDA issued Emergency Use Authorizations for the Pfizer-BioNTech and Moderna COVID-19 vaccines. Both vaccines require two doses for a completed series. The recommended interval between doses for the Pfizer-BioNTech COVID-19 vaccine is 21 days, and the recommended interval between doses for the Moderna vaccine is 28 days. However, the interval between doses can extend as long as 42 days.
On March 15, 2021, the CDC published a report showing that for persons who received a first COVID-19 vaccine dose and were eligible to receive a second dose, approximately 88% received a second dose, 8.6% had not received the second doses but remained within the allowable time to receive a second dose, and 3.6% missed the second dose.
The CDC notes that two doses of the Pfizer-BioNTech and Moderna COVID-19 vaccines are required for optimal vaccine efficiency. Click here for more details.
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