Dive Insight:

The risk of severe illness or death from COVID-19 is much lower in children than adults, particularly older adults. But children and adolescents are still susceptible to infection and in some, such as those with underlying conditions like asthma or who are immunocompromised, the risk of more severe symptoms is higher.

Between March 1 and April 30, there were approximately 1.5 million cases of COVID-19 among adolescents aged 11 to 17 that were reported to the CDC, the FDA noted in a statement accompanying Monday’s authorization.

“Today’s action allows for a younger population to be protected from COVID-19, bringing us closer to returning to a sense of normalcy and to ending the pandemic,” said acting FDA Commissioner Janet Woodcock in the statement. Pfizer and BioNTech’s original emergency use authorization, granted by the agency in December, was for individuals aged 16 and older.

The large Phase 3 trial used by the companies to support authorization mostly enrolled adults and teenagers older than 16. But about 2,300 adolescents between the ages of 12 to 15 were included, about half of whom received placebo.

The FDA noted side effects to vaccination among these younger children were similar to what was previously reported in study participants aged 16 years and older — most commonly injection site pain, tiredness, headache, chills or fever that was typically mild or moderate in degree.

Data on efficacy is more limited, and the agency relied on two measures to draw its conclusion that vaccination would be protective against COVID-19.

Results from a smaller group of 190 younger participants showed an immune response that was at least as strong as what was observed in a comparator group of 170 individuals aged 16 through 25 years old. Another analysis found no COVID-19 cases among 1,005 children aged 12 to 15 compared to 16 among 978 in the placebo group.

Data on whether immunization can prevent virus transmission, too, are limited, as are data on whether the durability of protection in younger vaccine recipients is different than in older teenagers or adults.

The FDA’s authorization follows a similar decision by Canadian regulators, which cleared Pfizer’s vaccine for use in 12- to 15-year-olds last week.

A clinical trial testing Moderna’s vaccine in adolescents between 12 and 17 years old has finished enrollment and showed strong protection in an initial analysis of some 3,200 participants. Moderna’s shot is only authorized in adults 18 years and older.

Both companies are studying their vaccines in children younger than 12. The FDA on Monday scheduled an advisory committee meeting for June 10 to discuss the data that would be required to further expand vaccine use into younger children. No specific vaccines will be evaluated at the meeting.

Just over 150 million adults in the U.S. have received at least one dose of Pfizer’s or Moderna’s vaccine, equal to about 58% of the country’s population over 18 years old. Another nearly 2.5 million adolescents aged 16 years and older appear to have received Pfizer’s vaccine, according to CDC data.