In all, researchers studied a total of 23.1 million records on individuals aged 12 or older between December 2020 and October 2021. In addition to the increased rate overall, the massive study confirmed the chances of developing the heart condition increased with a second dose, which mirrors other data that has been uncovered in recent months.
From the *peer-reviewed study, which was published by the Journal of the American Medical Association (JAMA):
“Results of this large cohort study indicated that both first and second doses of mRNA vaccines were associated with increased risk of myocarditis and pericarditis. For individuals receiving 2 doses of the same vaccine, risk of myocarditis was highest among young males (aged 16-24 years) after the second dose. These findings are compatible with between 4 and 7 excess events in 28 days per 100 000 vaccinees after BNT162b2, and between 9 and 28 excess events per 100 000 vaccinees after mRNA-1273.
The risks of myocarditis and pericarditis were highest within the first 7 days of being vaccinated, were increased for all combinations of mRNA vaccines, and were more pronounced after the second dose.”