FDA Authorizes Updated COVID-19 Vaccine for Children as Young as 6 Months Old

The U.S. Food and Drug Administration in White Oak, Md., on July 20, 2020. Sarah Silbiger/Getty Images

The U.S. Food and Drug Administration (FDA) has granted emergency authorization to the updated Pfizer-BioNTech COVID-19 vaccine as a booster for children as young as 6 months old, even though Pfizer has produced no clinical efficacy data for any age group.

FDA officials on March 14 said the emergency clearance was based on trial data that showed 60 children had “an immune response” after receiving the updated bivalent booster, and trial data that found 60 young children experienced side effects such as fatigue, diarrhea, and vomiting after bivalent vaccination.

None of the trial data has been released to the public.

The authorization means children aged 6 months to 5 years will be encouraged to get a booster dose just two months after the final dose of a three-dose Pfizer primary series.

The bivalent vaccines protected well against symptomatic infection for children aged 5 and older initially, but the protection waned to close to 50 percent after several months, according to federal data. There were no estimates for protection against severe illness.

Children are less likely to experience severe COVID-19 and many have already been infected, giving them protection that’s similar to or superior to vaccination.

A man fills syringes with COVID-19 vaccine booster shots at a COVID-19 vaccination clinic in San Rafael, Calif., on April 6, 2022. Justin Sullivan/Getty Images

The authorization provides parents “an opportunity to update their children’s protection by receiving a booster dose” of the updated vaccine, Dr. Peter Marks, an FDA official, said in a statement. “Currently available data show that vaccination remains the best defense against severe disease, hospitalization and death caused by COVID-19 across all age groups, and we encourage all eligible individuals to make sure that their vaccinations are up to date with a bivalent COVID-19 vaccine.”

Regulators were more cautious in their formal letter to Pfizer updating the emergency authorization. They said that, based on the scientific evidence available, “it is reasonable to believe” the bivalent “may be effective” and that it “is reasonable to conclude” the known and potential benefits outweigh the known and potential risks.

The authorization is for the prevention of COVID-19 disease.

The expanded authorization was also based on data for people who aren’t in the age group in question, including elderly people, and safety and effectiveness data for the monovalent vaccines, which were first rolled out in late 2020.

Some experts have said the vaccines shouldn’t be authorized without clinical efficacy data. Some have said the new vaccines aren’t necessary for most or all people, especially those who recovered from COVID-19. Others say the updated shots are a good option for people to have to boost antibodies, which are believed to protect against the disease.

Bivalent shots from Pfizer and Moderna were authorized and recommended in the fall of 2022 for adults. Access has since been expanded to all age groups. Regulators authorized Pfizer’s bivalent as the third dose of the three-dose primary series, and Moderna’s bivalent as a booster after a two-dose primary series, in late 2022.

Pfizer and BioNTech said earlier in the month that among 60 participants under 5, a fourth dose of the bivalent elicited a higher level of neutralizing antibodies compared to children in the age group who received three doses of the monovalent vaccine. The companies also said that the safety profile of the updated shot was “similar to that of the original vaccine.”