Overview reports inflammation of the heart muscle and pericardium

Until October 19, the Lareb Side Effects Center received 231 reports of inflammation of the heart muscle (myocarditis) and the pericardium (pericarditis) on 24 million corona vaccines given. These are known rare side effects of the Pfizer/BioNTech (Comirnaty) and the Moderna vaccine (Spikevax). People who experience chest pain, shortness of breath or palpitations after corona vaccination should always contact their doctor.

Total number of notifications

166 of the 231 reports involved pericarditis and 65 myocarditis. This concerns 156 reports on the Pfizer/BioNTech vaccine, 38 reports on the Moderna vaccine, 21 reports on the AstraZeneca vaccine and 15 reports on the Janssen vaccine. In one report, the vaccine was unknown. Pericarditis and myocarditis are known rare side effects of the Pfizer/BioNTech and the Moderna vaccine, but not of the AstraZeneca and Janssen vaccine. It was about as often the first as the second shot. Most of the reports concerned young men.

Serious Reports

Nearly half of the 231 patients have been hospitalized. A large proportion (60-70%) had recovered at the time of reporting. One man died from heart problems after myocarditis and one man from heart problems after pericarditis. Both received the Pfizer/BioNTech vaccine and were around 40 years old. The fact that myocarditis or pericarditis occurs after vaccination does not mean that the vaccine is always the cause. It can also have another cause, such as a (COVID-19) infection or immune disease. A man and a woman (50-55 years), both with myocarditis, died after the Janssen vaccine. This vaccine is not a known side effect.

Number of reports higher than expected

The number of reports has been compared with an estimate of the normal occurrence of myocarditis and pericarditis. In several age groups up to 40 years, the number of reports turned out to be higher than expected for the Pfizer/BioNTech and Moderna vaccine. Also with the AstraZeneca and Janssen vaccine, more reports were received in some groups than expected. The comparison does not take into account a possible increased number due to COVID-19 and that doctors are now more alert to this.

Watch out for complaints

Physicians and people who have been vaccinated should pay close attention to symptoms that may indicate myocarditis or pericarditis. Complaints are for example: shortness of breath, chest pain and palpitations that are sometimes irregular. Anyone who has these complaints should contact a doctor. The complaints usually go away on their own or can be treated well with medication.

More research

Studies show that the risk of myocarditis and pericarditis from a COVID-19 infection is greater than from the vaccines. More research is needed to determine how often these side effects occur, after which vaccine and who has an increased risk of these side effects.

More information

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