Cardiac risk from vaccines would be lower than from suffering from COVID

The inflammation of the heart that some people get after the COVID vaccine occurs much less frequently in response to the vaccine than after the disease itself, according to the largest study on the subject to date.

The first dose of vaccines from AstraZeneca Plc, Pfizer Inc. or Moderna Inc. may increase the risk of myocarditis, an inflammation of the heart muscle, as can Moderna’s second vaccine, researchers said Tuesday.

The two messenger RNA vaccines from Pfizer and Moderna only increased the risk in people younger than 40 years old.

Scientists at the University of Oxford found that the number of myocarditis cases was at least four times higher after having COVID-19. The risk from the vaccine, while rare, is a key point in the UK debate over licensing vaccines for children.

“We know that COVID-19 vaccines are highly effective in reducing the risks of serious outcomes”Said Julia Hippisley-Cox, a professor of clinical epidemiology and general practice at Oxford, who led the study.

“However, it is also important that we understand and identify the risks of these unusual diseases due to vaccines, to ensure that physicians know what to look for, aid early diagnosis, and inform clinical decision-making.”.

The study examined 38 million people over the age of 16 across the UK and examined the occurrence of cardiovascular complications within 28 days of vaccination or a positive COVID-19 test.

The researchers calculated that the additional cases of myocarditis were between 1 and 10 per million people in the month after vaccination, compared with 40 such events per million after an infection with SARS-CoV-2.

The study also showed an increased risk of pericarditis, a more localized form of inflammation, and irregular heartbeats after contracting COVID-19. The second dose of Moderna is associated with an increased risk of arrhythmia, according to the scientists.

This research did not include booster doses, which are a hot topic as governments weigh potential side effects against increased immunity in their populations as the new omicron variant spreads around the world.

Other limitations include the fact that young people between the ages of 16 and 40 were underrepresented in the sample, compared to those over 40 who participated.

In the United States, the Food and Drug Administration previously determined that the benefits of vaccination in people ages 16 to 17 outweigh the risk of myocarditis.