Heart failure and even death has occurred among people who received a COVID-19 vaccine, according to a new study.
Six people across the four Nordic countries died with myocarditis, a form of heart inflammation, within 90 days of hospital admission after being vaccinated with a messenger RNA (mRNA) vaccine, researchers reported. Twenty-two vaccinated people were diagnosed with heart failure within 90 days of hospital admission with myocarditis.
Myocarditis is caused by the mRNA COVID-19 vaccines made by Pfizer and Moderna, experts in the United States and elsewhere have said. Death is a known outcome. Many people diagnosed with the condition are hospitalized.
Many of the heart failure or death diagnoses happened in those 40 and older. Eight occurred among 12- to 39-year-olds.
Autopsies conducted in multiple countries have found that vaccine-induced myocarditis led to deaths in the young and middle-aged, and previous observational papers have identified post-vaccination deaths among those with heart inflammation.
The researchers also found that 62 people who experienced heart inflammation following vaccination were readmitted to a hospital within 90 days of discharge. Of the readmissions, 41 percent were among the younger age group.
The new study, published in the British Medical Journal on Feb. 1, drew from nationwide register data from Denmark, Finland, Norway, and Sweden. The data covered people aged 12 and up who had myocarditis listed as a main or secondary diagnosis for hospital admission since the start of the pandemic. Each country had different end dates for their portion of the study; the latest was April 30, 2022.
Because of the nature of the study, researchers said they could not say whether the six deaths following vaccination were caused by the vaccination “because these deaths could have been from other causes or from conventional myocarditis occurring by chance within 28 days of vaccination.”
More people experienced myocarditis after COVID-19 vaccination than after COVID-19—530 versus 109—according to the new paper.
Researchers took those numbers, and figures representing myocarditis cases prior to the pandemic. They then looked at what percentage led to heart failure or death and calculated the risk for each category.