Inflammation of the heart.
It has been argued that Infection can cause cardiovascular disease. Influenza can trigger various heart diseases and we can prevent many heart attacks with flu shots.
COVID 19 pandemic and COVID 19 vaccine
It was identified as a side effect of mRNA COVID 19 vaccines, especially for young males. Witberg2021myocarditis reported that the risk from the vaccination is 2.13 per 100,000 overall and 10.69 per 100,000 for males with age 16-29.
Yet, probably the most important data is that the myocarditis risk from COVID 19 infection is much higher (about 5x for young male and even higher for other groups). Heymans2021myocarditis provides clinical accounts and potential mechanisms, concluding that it is rare and mild, and that the risk is lower than the COVID 19 infection.
One less-known fact is that it is also a common complication of COVID 19 (Siripanthong2020recognizing, Imazio2021COVID 19) and that Infection can cause cardiovascular disease.
Daniels2021prevalence examines competitive athletes to measure the rate of myocarditis after infection showing that it can be from 0.3% (through symptom screening) to 2.3% (including subclinical cases). Patone2021risks found increased risk after vaccination and COVID-19 infection, while a higher risk with the infection (at least >6 times). Little2022myocarditis argues that the myocarditis risk for unvaccinated who got COVID (age 12-30) is 17 times higher than vaccinated.
CDC‘s research (Block2022cardiac) also found the same conclusion. The risk of cardiac complications is higher after COVID-19 infection than after mRNA vaccines (2-6x for 12-17 boys and 7-8x for 18-29 men).
What’s up with palpitation after vaccination?
That can be ranging from normal immune reaction (immune system working yay) to more serious myocarditis, which is known as a possible side effect of the vaccine. But of course it’s best to consult with doctors and important to report to the vaccine adverse event reporting system: https://vaers.hhs.gov
This https://www.nejm.org/doi/full/10.1056/NEJMoa2110737 study reports the risk of myocarditis to be ~0.002% (for all groups) and this https://www.nature.com/articles/s41591-021-01630-0 study estimates lower than 0.001%. Some people with mild symptoms might have not reported it, so the actual number can be higher.
This https://jamanetwork.com/…/jamacardi…/fullarticle/2780548 study (with many IU researchers) reported that 0.31% of atheletes who got covid had symptomatic myocarditis but it was 2.3% if they included every case (including those that were too mild to notice).
Probably the most important result from studies is that the risk of myocarditis from COVID is much higher (5x-20x) than that from the vaccine (I think it makes sense that the real thing has a higher risk) and COVID can also induce all kinds of heart problems other than the myocarditis. Even worse, it can happen long after the infection (https://www.science.org/content/article/covid-19-takes-serious-toll-heart-health-full-year-after-recovery). People tend to suffer from all kinds of heart problems long after getting the covid… 🙁