Updated COVID-19 Vaccine data supporting efficacy in children 6 months through 4 years of age.

Emergency Use Authorization (EUA) of this vaccine was granted by the FDA for this age group on June 17 and an application for conditional Marketing Authorization in this age group is under review by the European Medicines Agency (EMA).

Participants in the study received either the Pfizer-BioNTech COVID-19 Vaccine (3-?g) as a three-dose series or placebo (2:1 randomization). Vaccine efficacy, a secondary endpoint in the trial, was 73.2% (2-sided 95% CI: 43.8%, 87.6%) among children 6 months through 4 years of age without evidence of prior COVID-19 infection. This analysis was based on 13 cases in the Pfizer-BioNTech COVID-19 Vaccine group (n=794) and 21 cases in the placebo group (n=351), diagnosed from March to June 2022.

The study protocol specified that this formal efficacy analysis should be performed when at least 21 total symptomatic COVID-19 cases were identified, each at least seven days after the third dose. Consistent with the time period when the cases occurred, sequencing of viral RNA from illness visit nasal swabs indicated that observed cases were primarily caused by Omicron BA.2. Omicron BA.4 and BA.5 strains were emerging during the period of the study, with only a few cases accrued and efficacy results against these strains were inconclusive. Consistent with our approach in adults, Pfizer is working with the FDA to prepare an EUA application for an Omicron BA.4/BA.5-adapted bivalent vaccine in children 6 months through 11 years of age.