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.