A new study in Israel found that the risk of myocarditis among men ages 16 to 19 is about 1 in 15,000 after the third dose of Pfizer-BioNTech's COVID-19 vaccine, according to a new study published in the journal Circulation. Several previous studies and reports from public health agencies around the world have pointed to a possible link and potentially increased risk of myocarditis after receiving the COVID-19 vaccine mRNA. Myocarditis is generally thought to be caused by a viral infection and is an inflammation of the middle layer of the heart muscle wall, the myocardium. This disease is infrequent and can temporarily or permanently weaken the heart muscle and the electrical system of the heart that keeps the heart beating normally.  The Israeli Ministry of Health recently published research detailing post-vaccine myocarditis in the country after the first and second doses of Pfizer-BioNTech's COVID-19 vaccine. The incidence of myocarditis was low, but after the second COVID-19 vaccination, it was seen mostly in young men, suggesting a potential link between the vaccine and myocarditis.  A cardiologist and rheumatologist analyzed data based on the Brighton Collaboration's myocarditis case definition. Specifically, the analysis showed that after a 30-day follow-up: - There were fewer than 100 cases (91) of myocarditis within the first 30 days after receiving the COVID-19 booster (3rd dose) of Pfizer-BioNTech's COVID-19 vaccine. - Among all age groups, the risk of developing myocarditis was almost nine times higher in men than in women (1.42 versus 0.16). - Men 16-19 years old had the highest risk of developing myocarditis at 6 cases per 100,000, followed by men 20-24 years old (5.21 cases per 100,000), 30-39 years old (1.81 cases per 100,000) and 25-29 years old (0.79 cases per 100,000).