Does anyone know why ? I mean I kind of understand that heart problems are more common in older people, and COVID-19 is worse for older people, so that'd explain the age differences. But the sex differences ?
I've heard heart disease is sometimes overlooked in women, so could these numbers show not the real risk but the underdiagnosing for women ? Or that's for other heart diseases and not myocarditis?
I know a woman over 50 who is going to get a moderna booster tomorrow. She got 2 doses of Pfizer before with mild secondary effects. The week after the second dose she felt weaker at sport (leisure) but otherwise fine.
The question is : does 3rd dose Moderna in this study mean the counted people all got 3 dosis of Moderna or do they also count 2 pfizer + 1/2 Moderna ? Maybe they looked at the UK and they haven't mixed brands there ?
The difference between men and women regarding myocarditis appears to be linked to testosterone levels, which increases inflammation and scarring in the heart. While estrogen (female sex hormone) appears to have a protective effect.
I would assume that's the reason why mostly younger men are affected by the vaccine compared to older men due to Covid.
Men are more affected then women:
https://pubmed.ncbi.nlm.nih.gov/19710029/
In patients with clinically acute myocarditis, myocardial fibrosis was more frequent in men and in patients younger than 40 years. Injury sustained in younger patients appears to be more regional and more severe, as indicated by a higher incidence of irreversible injury.
Women are also affected by Cardiovascular diseases (CVD):
https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3318944/
Sex hormones play a major role in the pathogenesis of CVD, as reflected by a higher incidence and severity of CVD in men than women across all age groups. Estrogens are protective for heart physiology and prevent or delay CVD. Evidence that the incidence of CVD increases in women as estrogen declines with age and menopause, further supports a protective role for estrogens in the heart. Sex differences in the incidence of CVD are also influenced by gender differences in cardiovascular risk factors and presentation of disease. Although CVD occurs more frequently in men, it is also the leading cause of death in women, just as it is for men. For this reason it is critical that researchers and clinicians gain a better understanding of the factors that contribute to CVD in both men and women.
Sex differences exist in normal heart physiology and function. For example, men have larger hearts (left ventricular mass), cardiac contractility is greater in healthy women than age-matched men, myocardial mass is better preserved in women as they age, cardiac apoptosis is threefold higher in men compared with women as they age, women have smaller coronary vessels than men and pre-menopausal women have lower blood pressure but a faster resting heart rate than men. Many other sex-specific differences exist in the hearts of apparently normal men and women according to microarray and proteomic analyses. For example, in the aging female heart, hypertrophy, apoptosis and fibrosis are less pronounced than in the aging male heart. These underlying sex differences in cardiac function directly influence the immune response to infection and injury in the heart.