The application comes after Pfizer released data earlier this month from a small lab study of blood samples from 30 kids in the age group, which showed a 36-fold increase in antibody levels against the omicron variant compared to two doses of the vaccine.
The booster shot is a 10-microgram dose, the same level as the primary vaccination series for the age group. The third shot did not demonstrate any new safety concerns in the trial, according to Pfizer.
Only about 28% of children ages 5 to 11 had received their primary series of two doses as of April, according to CDC data.
The FDA previously authorized Pfizer booster doses for teenagers 12 to 15-years-old in January as the omicron variant swept the nation. The protection the vaccines provide against infection has declined over time, particularly in the context of omicron, which is adept at evading the antibodies that block the virus from infecting human cells. However, the vaccines are still providing strong protection against severe illness.
It’s unclear whether the FDA’s advisory committee will meet to discuss the data and make a recommendation. The FDA did not call meetings of the outside expert panel before authorizing third shots for kids ages 12 to 15 in January and fourth shots for people ages 50 and older last month.
Members of the FDA panel as well as the Centers for Disease Control and Prevention’s advisory committee have criticized the agencies for repeatedly moving forward with expanded booster eligibility without consulting them. Several experts on the CDC committee, in a public meeting last week, said trying to stop infections with the current vaccines is an unachievable goal. The CDC committee members largely agreed that public health authorities should tell the public more clearly that the goal of the vaccines is to prevent severe illness, which the shots have largely achieved.
Pfizer is also seeking FDA authorization for its three-shot vaccine for children under 5-years-old, the only age group left in the U.S. that is not eligible for vaccination. CEO Albert Bourla, in a podcast interview last week, said he hopes the vaccine for that age group will receive authorization in June. The shots for the youngest kids have a much smaller 3-microgram dosage level.