Moderna Inc. applied for emergency use authorization for its COVID-19 vaccine in children from six months to under 6 years old after a successful trial showed two doses generate high levels of antibodies to the virus.
The highly anticipated application comes just over a month after Moderna said a large trial showed two low doses of its vaccine produced powerful immune responses in young kids. Even though its effectiveness against omicron-related infections is modest, the application will put tremendous pressure on the Food and Drug Administration to quickly make a decision on whether to authorize it.
Similar submissions for clearance are underway with regulators outside the U.S., Moderna said Thursday in a statement. Meanwhile, Moderna has also initiated a submission for authorization of its vaccine for use in kids ages 6 to 11.
While the vaccine from partners Pfizer Inc. and BioNTech SE is authorized for kids 5 and up in the U.S., there is no COVID vaccine those under 5, much to the consternation of many parents. More than 900 doctors sent a letter Wednesday to FDA Commissioner Robert Califf asking for quick review of a vaccine for young children.
Pfizer’s effort to bring forward a vaccine for the youngest children was delayed after immune responses from two doses appeared insufficient in some, and the company decided to wait for results from a third. But in an interview, Moderna Chief Medical Officer Paul Burton said the immune response generated by two doses of its vaccine should be enough to provide significant protection against severe disease in very young kids.
“There is an important unmet need here,” Burton said. The two-dose regimen “should be sufficient for primary vaccination” in the young kids, as it produced antibody levels similar to the levels that showed protection against serious disease in younger adults, he said.
Moderna received no indication of whether the FDA would wait for Pfizer’s upcoming three-dose data in young kids before deciding what to do with the company’s two-dose regimen, Burton said.
“We have shown effectiveness, we have shown expected levels of antibody production, we have looked at safety and this appears safe,” said Burton. He said the trial showed no unexpected side effects in the young kids and that rates of vaccine-induced high fevers were very low.
In March, Moderna said a large trial showed its vaccine produced high levels of protective antibodies in young children. In the study, almost 7,000 children ages 6 months through 5 years old received two 25-microgram doses of the vaccine — a quarter of the adult dose. The shots hit their primary goal, producing antibody levels equivalent to those raised in previous, successful trials in younger adults.
Yet the vaccine was only modestly successful at preventing cases of COVID in the trial. Moderna said Thursday that the shot was 51% effective in preventing infections in kids ages 6 months to under two years old, according to PCR tests. It was 37% effective in preventing confirmed infections for kids ages 2 years through 5 years old, the company said.
The child trial was conducted during the omicron period, and Moderna said the efficacy numbers were similar to vaccine efficacy against Omicron in adults who had received two Moderna doses.
Unlike the Pfizer shot, Moderna’s vaccine has U.S. clearance only for adults. Moderna’s application for authorization of its vaccine in adolescents has been held up for months in the U.S. over concerns about rare cases of heart inflammation. The company recently submitted follow-up safety and efficacy data on adolescents at FDA’s request, which the agency is now reviewing, according to a spokeswoman.
The U.S. campaign to vaccinate children has tapered off, with only 28% of children ages 5 to 11 fully vaccinated, according to data from the Centers for Disease Control and Prevention. And among adolescents ages 12 to 17 who are already eligible for a booster shot, fewer than a quarter have received one.
