Researchers at Mayo Clinic are looking into rare cases of myocarditis (inflammation of the heart muscle) in young men who experienced symptoms after receiving the second doses of Moderna or Pfizer's messenger RNA (mRNA), COVID-19 vaccines. Recent studies have shown that hypersensitivity myocarditis is a rare side effect of being vaccinated for COVID-19. Researchers stress that this awareness does not mean that vaccinations should be stopped during this current pandemic.Although there are more cases of myocarditis after vaccinations than in the baseline, it is still a serious condition that can lead to death and heart damage. A majority of those who become seriously ill from COVID-19 have an injury to the heart. Nearly 1% of athletes who were infected with mild COVID-19 show myocarditis when they are scanned.In JAMA Cardiology, a retrospective case series examined 23 U.S. soldiers who developed myocarditis symptoms after receiving the second dose. Three patients had previously been infected by COVID-19 and symptoms began after receiving the second dose. These cases were reported between January and April. Sixteen of the cases had been treated with the Moderna vaccine, while seven received the Pfizer vaccine. It is important to remember that more than 2.8 Million doses of messengerRNA COVID-19 vaccines were administered by the military during this period.All 23 military patients experienced severe chest pains and elevated levels of cardiac troponin, a protein marker that can be used to assess heart damage. The rapid recovery of each patient, along with the timing and symptoms support the diagnosis, hypersensitivity myocarditis. Although this rare type of myocarditis is often due to drug allergies, it has also been linked to smallpox vaccinations."Hypersensitivity myocarditis after vaccination is uncommon, with the exception being smallpox vaccine." Leslie Cooper M.D. is the chair of the Department of Cardiology at Mayo Clinic, Florida. The study was done with U.S. military hospitals. Dr. Cooper is the senior author.A second observational study gathered details about eight men aged between 21 and 56 who were admitted to hospital with chest pain. They were diagnosed with myocarditis using laboratory and cardiac MRI. Within two to four days after receiving their second COVID-19 vaccination, the patients experienced symptoms that included a fever and other signs. One patient, who had been treated with COVID-19 before, developed symptoms shortly after receiving the second dose. The effects of myocarditis were reversed in all eight patients. They also experienced no chest pain. Circulation published Dr. Cooper's findings with researchers from Mayo Clinic, Italy and other medical institutions in the U.S.Because the risks and benefits are so low, everyone should get the COVID-19 vaccine. Dr. Cooper says that almost all cases of vaccine-associated myocarditis are resolved quickly by increasing research.
