US Military Confirms Myocarditis Spike After COVID Vaccine Introduction

There were 275 cases of myocarditis in 2021—a 151 percent spike from the annual average from 2016 to 2020, according to Gilbert Cisneros Jr., undersecretary of defense for personnel and readiness, who confirmed data revealed by a whistleblower earlier this year.

The COVID-19 vaccines can cause myocarditis, a form of heart inflammation that can lead to mortality, including sudden death. COVID-19 also can cause myocarditis.

The diagnosis data comes from the Defense Medical Epidemiology Database.

Mr. Cisneros provided the rate of cases per 100,000 person-years, a way to measure risk across a certain...