Pfizer and BioNTech on Monday said their coronavirus vaccine Comirnaty is safe and spurred virus-fighting antibodies in children between 5 and 11 years old, a crucial finding that could pave the way for regulatory clearance and an immunization campaign in that age group within months.
The results, announced by press release on Monday, come from a group of young trial volunteers given a much smaller two-dose regimen of Corminaty than is used in adults. Pfizer and BioNTech reported that the immune response observed in children was similar to what was seen in 16- to 25-year-olds who had received a dose that's three times larger.
While the study was not big enough to assess whether immunization prevented infections or disease, other vaccines for children have been approved based on similar findings.
The side effects reported were similar to what trial enrollees between 16 and 25 years of age have experienced after vaccination, the companies said. They didn't specify, however, whether trial investigators observed any cases of myocarditis or pericarditis, a type of heart inflammation that has been reported in some younger men who have received Pfizer and BioNTech's vaccine and is a key concern for regulators. Myocarditis is also associated with COVID-19.
Pfizer and BioNTech will seek clearance from regulators in the U.S. and Europe in the "near term," the companies said.
With a majority of U.S. adults immunized against COVID-19, children are currently much more vulnerable to infection and symptomatic disease. Though children don't experience COVID-19's worst health outcomes as often, the spread of the infectious delta variant, the start of the school year and a rise in pediatric hospitalizations have heightened the urgency to make a protective shot available.
"Since July, pediatric cases of COVID-19 have risen by about 240 percent in the U.S. — underscoring the public health need for vaccination," Pfizer CEO Albert Bourla said in a statement.
The data come from a subset of Pfizer's study, which evaluated two doses of the shot in 4,500 children as young as 6 months old. Children between 5 and 11 received two, 10-microgram shots of the vaccine spaced three weeks apart, while those younger than 5 received 3-microgram shots. (Adults and older children, by comparison, get two 30-microgram doses.) Researchers evaluated levels of neutralizing antibodies — which block the coronavirus from entering cells — one month after the second shot.
Antibody levels among the 2,268 children in the 5-11 age group were "non-inferior" to those seen in 16-25 year olds who received the typical, larger dose, a group Pfizer used as the statistical control arm.
Pfizer and BioNTech's COVID-19 rival, Moderna, meanwhile, isn't far behind. The biotech has fully enrolled a study in a similar age group, and reportedly could disclose results before the end of the year. Like Pfizer, Moderna is giving children a smaller dose of its vaccine and measuring immune responses a month after the second shot.
Pfizer's vaccine is already cleared for use in people as young as 12 years old, while Moderna's is only authorized for adults 18 years and older. Pfizer has also won support for a third shot in certain people, with the FDA granting emergency use for some immunocompromised people last month. On Friday, agency advisers backed clearing a third shot for older people and those in high-risk jobs. Those advisers, however, opposed broader use of a third shot in anyone over the age of 16, as Pfizer had initially sought.