Federal authorities have received over 800 reports of heart inflammation in people who received a COVID-19 vaccine, a health official said Thursday. The reports of myocarditis or pericarditis were submitted to the Vaccine Adverse Event Reporting System, a passive reporting system run jointly by the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration, through May 31. The bulk of the reports described heart inflammation appearing after the second of two doses of either the Pfizer of Moderna vaccines, both of which utilize messenger RNA technology. Authorities stress that anybody can submit reports through the reporting...