Moderna said on Wednesday it would seek urgent approval for its coronavirus vaccine for children under 6 years of age after interim results from its clinical trial showed that volunteers in that age group had a similar immune response to young adults when given a dose equal to one-fourth the dose. strong.
But the company said the vaccine was found to be only about 44 percent effective at preventing symptomatic disease in children 6 months to 2 years old, and 37 percent effective in children 2 to 5 years old. The company is studying the effectiveness of a booster injection, and one of its top officials said it expects a booster to be needed for that age group, just as it would for adults.
dr. Jacqueline Miller, the company’s senior vice president for infectious diseases, said the relatively low level of protection showed the Omicron variant was able to evade the vaccine’s shield. Nevertheless, she said in an interview, “What we have seen is a successful trial.”
“What I will say is 37.5 percent and 43.7 percent is above zero,” she said. “If I were the parent of a young child, I wish there was some protection on board, especially if we see a new wave of infections.”
The company’s announcement comes shortly before Pfizer and BioNTech are expected to release the results of a triple study for children under five, using doses one-tenth as strong as those for people 12 years and older. Those results are expected in April.
At the request of the Food and Drug Administration, Pfizer-BioNTech submitted preliminary results from their trial last month; regulators hoped the data on two doses would be strong enough to kick-start the vaccination campaign, pending the final results of three.
But the FDA changed its mind when new data collected during the Omicron wave convincingly showed that two doses did not provide adequate protection against symptomatic infection. Pfizer and BioNTech haven’t released the exact results publicly, but in December they reported that two doses of their vaccine elicited a strong immune response in children 6 months to 2 years old, but not in children 2 to 4 years old.
Children under 5, a group of about 18 million, are the only Americans still not eligible for injections.
In a statement, Stéphane Bancel, Moderna’s general manager, said the company will also apply for an emergency license for its two-shot vaccine for children ages 6 to 11, and was updating a similar request it filed last summer for those aged 12 to 17. The request was shelved because the Food and Drug Administration wanted more data on a rare side effect, myocarditis, which involves inflammation of the heart.
So far, the Pfizer-BioNTech shot is the only one authorized for Americans 5 through 17.
About 6,900 children in the United States and Canada participated in the Moderna study for children under 6. Moderna said there were no cases of serious illness, hospitalization or death in the placebo or vaccine arms. Most infections were mild.
The children who received the vaccine showed a similar response in the level of neutralizing antibodies as adults ages 18 to 25, meeting the primary endpoint set by the FDA for a successful trial, the company said.
Because of the Omicron spike, there were enough infections to also evaluate the vaccine’s efficacy against symptomatic diseases, Moderna said. The relatively low efficacy is consistent with research on how well vaccines have protected adults against the Omicron variant, it said. Moderna is studying booster shots for all three age groups under 18.
“We definitely plan to boost these children,” said Dr. Miller. “And don’t forget, we found that we had to administer a booster dose to adults to maintain a high level of vaccine effectiveness against the Omicron variant.”
Most adverse reactions were mild or moderate and fever was typical of existing pediatric vaccines. A few children — 0.2 percent of the study group — developed fevers over 104 degrees, the company said.
