In the news: myocarditis and breakthrough COVID infections after vaccination.

Recently there have been a number of reports in the news about heart issues after vaccination. Myocarditis, an inflammation of the heart muscle, and pericarditis, an inflammation of the outer lining of the heart, have been reported in some young people after receiving the second dose of the mRNA based COVID vaccines. In both cases, the body’s immune system causes inflammation in the heart due to some trigger. The concern is that immune stimulation from the vaccine can cause this inflammation.

The Centers for Disease Control and Prevention (CDC) is monitoring a small number of these cases mainly in teens and young adults not long after mRNA COVID-19 vaccination. In analyzing these reports several things become obvious.

CDC Headquarters in Atlanta

Myocarditis and pericarditis after COVID-19 vaccination are rare. As of June 9, 2021, the government’s adverse event reporting system has received 623 reports of myocarditis or pericarditis among people age 30 and younger who received COVID-19 vaccine. Most cases have been reported in male adolescents and young adults. Through follow-up, including medical record reviews, the CDC and FDA have confirmed 268 reports of myocarditis or pericarditis. The CDC and its partners are investigating these reports to assess whether there is a relationship to COVID-19 vaccination.

Importantly, no one has been disabled or failed to recover from these symptoms, and no one has died from myocarditis.

Given the total number of people who have now been vaccinated, even if every one of the 268 reports is correct, it would represent 1.5 cases in every million people immunized in the U.S.A. 

Therefore, given the low frequency of these reports and the fact that this has not resulted in any serious illness or death, the CDC has not limited the vaccine’s use in any way. While it remains important to look for these types of side effects, the risk of the vaccine is much lower than the risk from COVID, even in a younger age group.

“Breakthrough” infections with COVID-19 are also in the news. These are infections that occur in fully immunized people and have most recently been identified in two Royal Caribbean cruise ship passengers

While the vaccines are 95% effective in preventing infection, it is clear that some people (5%) will become infected despite the vaccine. There are several important points to understand about these infections.

First, these people didn’t get sick. The only reason these individuals were identified is the fact that the cruise ships are screening folks all the time looking for evidence of virus. The statement from Royal Caribbean made clear that the “two guests sharing a stateroom onboard Celebrity Millennium who tested positive for COVID-19 during the required end of cruise testing are asymptomatic and currently in isolation and being monitored by our medical team.”

It is important to remember that even if you are the rare person to get infected after COVID-19 vaccine, you do not get sick! COVID-19 vaccines not only prevent infection with SARS-CoV-2, but also prevent illness.

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

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