Moderna Doubles Kids Vaccine Trial Group After FDA Request

(Bloomberg) -- Moderna Inc. plans to double enrollment in a trial of its Covid vaccine in children under age 12, following a request from U.S. regulators to collect additional safety data.

Moderna’s study will enroll an estimated 13,275 participants ages 6 months up to 12 years old, according to a listing on the clinicaltrials.gov website. In a post from late July, the Cambridge, Massachusetts-based company said it would seek to enroll about 7,000.

A surge in Covid-19 infections among children driven by the delta variant has raised increasing concerns as the fall resumption of school looms. Moderna said last month that it would expand the trial at the request of U.S. regulators, who were seeking additional data amid worries that messenger RNA shots may trigger rare heart side effects. Pfizer Inc. and its partner BioNTech SE have also said they intend to expand the size of their under-12 study.

Moderna spokesman Ray Jordan confirmed that the new enrollment estimate reflects the company’s effort to expand the trial in young children following discussions with the U.S. Food and Drug Administration.

Moderna said in July that it expects to report data from the under-12 trial later this year or at the outset of 2022. “Because the various age groups enroll at different times, it is possible that interim data would be available in various time stages,” Ray Jordan, a spokesman, said Wednesday in an email.

Moderna’s vaccine is authorized in the U.S. for use in those 18 and older. The company sought authorization for its two-shot regimen in 12- to 17-year olds in June, the FDA has not yet cleared it for use in that group.

Meanwhile, the Pfizer-BioNTech vaccine has been authorized for use in those 12 and up since May. The rollout of shots to adolescents has moved slowly, however, with fewer than half of 12- to 17-year-olds having received at least one shot.

Pfizer and BioNTech are poised to be the first to report on their mRNA vaccine’s performance in the under-12 population, with initial data coming as soon as September.

Pfizer Chief Executive Officer Albert Bourla told Bloomberg in late July that the company would expand the size of its trial in young children, but the drug giant hasn’t yet disclosed how many will ultimately be enrolled. Currently, a Pfizer-BioNTech post suggests enrollment for the under-12 age group is estimated at 4,500.

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