Published May 2021 | New England Journal of Medicine

It was the news that pediatricians worldwide were waiting for: The Pfizer-BioNTech vaccine BNT162b2 not only showed a favorable safety and side-effect profile, the observed efficacy in a clinical trial setting was 100% among participating teens aged 12 through 15.

Robert Frenck, MD, was lead author for the pivotal study, which supplied the data needed for the U.S. Food and Drug Administration to grant emergency use authorization (EUA) of the first vaccine for use below age 16 in the United States. Frenck was one of more than 20 key co-authors from the C4591001 Clinical Trial Group that had been evaluating the vaccine.

BNT162b2 received its initial EUA for adult use on Dec. 11, 2020. The FDA granted the EUA for ages 12 and up on May 10, 2021, acting on the data even before the full findings were published.

Overall, 2,260 teens participated; with 1,131 receiving BNT162b2, and 1,129 receiving placebo. Headache and fatigue were the most frequently reported systemic events. Severe adverse events were reported in 0.6% of vaccine recipients in the 12 to 15 age group vs. 1.7% among those 16 to 25.

This paper, one of several published as scientists tested various vaccines across age groups, generated hundreds of news articles and more than 9,000 Twitter messages from people with a combined following of nearly 20 million people.

Frenck gave numerous interviews as parents asked questions about the vaccine. He stressed that no corners were cut on safety even though results from the clinical trial were rapidly gathered and communicated. Availability of the vaccine to most junior and senior high students (in addition to adult staff) helped officials re-open nearly all U.S. schools for in-person learning in fall 2021.

Vaccine Efficacy against Covid-19 in Participants 12 to 15 Years of Age

A chart showing vaccine efficacy against Covid-19 in participants 12 to 15.

While some teens receiving placebo in the clinical trial went on to test positive for COVID-19, none of those who received the vaccine tested positive during the study period.