New Study Finds Heart Inflammation After COVID-19 Vaccination Higher With Moderna Than Pfizer

A nurse fills up a syringe with the Moderna COVID-19 vaccine in a file image. Sergio Flores/Getty Images

A new study estimated that hundreds of cases of heart inflammation occur in every million second doses of Moderna’s COVID-19 vaccine in the highest-risk group.

Some 269.5 cases of myocarditis, a form of heart inflammation, were estimated for men aged 18 to 29, researchers concluded.