Myocarditis is a heart condition that can be caused in young men by the mRNA Covid vaccine, particularly Moderna's product.
As explained by a published report on a large Canadian study, in November 2022:
“ | Males aged 18-29 were at the most risk of developing the condition, especially if they received the Moderna vaccine twice. Overall myocarditis rates among males in this age group were 2.97 per 100,000, which rose to 2.27 per 100,000 after the second dose. Among men ages 18 to 29 who received the Moderna vaccine, the rate was 22.9 per 100,000 doses.[1] | ” |