The U.S. Food and Drug Administration authorized emergency use of the Pfizer-BioNTech COVID-19 Vaccine and Moderna COVID-19 Vaccine for children 6 months and older. Pfizer makes a two-dose vaccine series for adults and adolescents 12 and older that has a 30-mcg dosage, a two-dose series for children 5 to 11 years old that is one third of the adult dosage (10 mcg), and a three-dose series for children 6 months to 4 years old that is one tenth of the adult dosage (3 mcg). Moderna makes a two-dose vaccine series for adults and adolescents 12 and older that has a 100-mcg dosage, a two-dose vaccine series for children 6 to 11 years old that is one half of the adult dosage (50 mcg), and a two-dose vaccine series for children 6 months to 5 years old that is one quarter of the adult dosage (25 mcg).

Clinical trial data showed that a smaller dose for children produced a strong immune response (very similar to that of adults) and caused fewer side effects than an adult dose. For more information about the safety, efficacy, and timing of each pediatric vaccine, please visit CDC’s page about COVID-19 Vaccines for Children and Teens.

The CDC recommends people 5 and older receive an age-appropriate, updated mRNA booster dose if at least 2 months have passed since their primary series or since their most recent booster dose. The updated Pfizer-BioNTech booster for people is available for people 5 and older, and the updated Moderna booster is available for people 6 and older. Pfizer’s bivalent booster for children 5 to 11 years is 10 mcg, one third of the adult bivalent booster dosage. Moderna’s bivalent booster for children 6 to 11 years is 25 mcg, one half of the adult bivalent booster dosage.