FDA Has Results of Subclinical Myocarditis Studies, but Won’t Release Them Yet

‘I really don’t think FDA has a leg to stand on here,’ former FDA officer says.

A medical assistant holds a tray of syringes filled with doses of Moderna COVID-19 vaccine at a vaccination site in Los Angeles on Feb. 16, 2021. Apu Gomes/AFP via Getty Images

The U.S. Food and Drug Administration (FDA) has received results from two studies of subclinical heart inflammation following Moderna COVID-19 vaccination, but is refusing to release them to the public—at least for now.

FDA officials in January 2022 directed Moderna to run three prospective studies on subclinical myocarditis, or heart inflammation without symptoms, after COVID-19 booster vaccination. One study, mRNA-1273-P204, would examine the incidence of subclinical myocarditis in children aged 6 months through 11 years. Another, mRNA-1273-P203, would examine the incidence in adolescents aged 12 years through 17 years. The third, mRNA-1273-P301, would examine the incidence in adults.