Moderna Doubles Children’s 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 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.

Dangerous Covid infections in children have raised increasing concerns as the delta variant spreads across the U.S., and the fall resumption of classes 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 didn’t immediately respond to a request for comment. The biotechnology company’s vaccine is currently authorized in the U.S. for use in those 18 and older.

The Pfizer-BioNTech vaccine is the only one cleared in U.S. for those 12 through 17. But the rollout of shots to adolescents has moved slowly, with fewer than half that cohort having received at least one shot.

The partners 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, the Pfizer-BioNTech clinicaltrials.gov posting suggests enrollment for the under-12 age group is estimated at 4,500.

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