A study of U.S. military members who were vaccinated against COVID-19 found a higher than expected rate of heart inflammation reported by those who received the vaccine, though cases of this adverse effect are still extremely rare.
The study, published Tuesday, took a retrospective look at patients serving in the military who were vaccinated with an mRNA vaccine between January and April 2021. A total of 23 male patients ages 20-51, 22 of whom are currently serving and one who is retired, showed symptoms associated with myocarditis (heart inflammation) within four days after receiving their vaccine shots. These patients received either the Pfizer and BioNTech or Moderna vaccines.
Throughout this period, the military administered more than 2.8 million vaccine doses. Estimates predicted that eight or fewer patients would report heart inflammation out of the 436,000 male military members who received two COVID-19 vaccine shots.