Pfizer, BioNTech Announce Updated COVID-19 Vaccine Efficacy Data for Young Children

Pfizer and BioNTech announced updated efficacy results from a phase 2/3 trial, evaluating a 3 3-µg dose series of the Pfizer-BioNTech COVID-19 vaccine in children aged 6 months through 4 years of age, reinforcing interim vaccine efficacy data.

The previously reported data were collected in March and April 2022, with the FDA granted emergency use authorization of the vaccine for this age group on June 17, 2022.

An application for conditional marketing authorization in this age group is also under review by the European Medicines Agency (EMA).

Individuals in the study received either the Pfizer-BioNTech COVID-19 vaccine as a 3-dose series in the 3-µg strength or a placebo. The individuals were randomized 2 to 1.

Investigators found that vaccine efficacy, which was a secondary endpoint, was 73.2% among children aged 6 months through 4 years of age without evidence of prior COVID-19 infection. The analysis was based on 13 cases in the vaccine group and 21 cases in the placebo group, which were diagnosed between March and June 2022.

The formal efficacy analysis was performed when at least 21 total symptomatic COVID-19 cases were identified, with each being at least 7 days after the third dose, according to the study protocol. Investigators noted that the observed cases were primarily caused by the Omicron BA.2 variant, because of the time when all the cases occurred.

The Omicron BA.4 and BA.5 strains caused just a few cases, so the efficacy results against these strains were inconclusive.

“While these results confirm that 3 3-µg doses of our COVID-19 vaccine provide young children with a high level of protection at a time when the Omicron BA.2 strain was highly prevalent with a favorable safety profile, we are also developing an Omicron BA.4/BA.5-adapted bivalent vaccine in this age group to address these sublineages,” Ugur Sahin, MD, CEO and co-Founder of BioNTech, said in a statement.

The companies are preparing an EUA application for an Omicron BA.4/BA.5-adapted bivalent vaccine for adults and children aged 6 months through 11 years.

Investigators also found that among children aged 6 through 23 months, the vaccine was 75.8% effective at preventing COVID-19, with 4 cases in the vaccine group and 8 cases in the placebo group, after a median of 1.9 months after the third dose.

For children aged 2 through 4 years, the vaccine was 71.8% effective at preventing COVID-19, based on 9 cases in the vaccine group and 13 cases in the placebo group, after a median of 2.4 months after the 3 doses.

The 3 doses of the Pfizer-BioNTech COVID-19 vaccine continues to be well tolerated in this age range, with the majority of adverse events observed being mild or moderate in severity, with a safety profile similar to the placebo.

The companies plan to submit the updated efficacy data to the EMA, FDA, and other regulatory agencies in the coming weeks.

Reference

Pfizer and BioNTech announce updated COVID-19 vaccine data supporting efficacy in children 6 months through 4 years of age. News release. Pfizer. August 23, 2022. Accessed August 23, 2022. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-updated-covid-19-vaccine-data