The risk of myocarditis after an mRNA vaccination seems to be higher than previously assumed, especially in adolescents and young men.

Frankfurt – The mRNA vaccine from the US manufacturer Moderna * has not been used at all in Iceland since Friday (November 5th, 2021), the country’s health department announced on its website Covid.is. In Sweden and Finland, the corona vaccine * should no longer be administered to men under 30 for the time being, and in Norway and Denmark no longer to under 18-year-old male adolescents. In Great Britain, Hong Kong and Norway, according to a report in the “New York Times”, there are also considerations to administer the mRNA vaccine from Biontech / Pfizer * to adolescents only to a limited extent – specifically: to give only a single dose and no double vaccination.

As different as these steps are in detail, there is a common background: The risk of myocarditis *, an inflammation of the heart muscle, after an mRNA vaccination against Corona * seems to be higher than previously thought, especially in male adolescents and young men – even if this complication continues to be a rare occurrence.

Heart muscle inflammation after corona vaccination – the clinical picture:

Myocarditis is an inflammatory disease of the heart muscle, with pericarditis the pericardium that surrounds the heart is affected.

trigger are often viruses. Defense cells of the immune system can also damage the tissue.

The symptoms are often unspecific. Both diseases can manifest themselves in tiredness, weakness, shortness of breath, palpitations and heart pain.

A complete cure can be expected in 70 percent of cases, according to the Heart Foundation. Long-term consequences can be cardiac arrhythmias or, rarely, heart failure. pam

The vaccine from Moderna, trade name Spikevax, is particularly affected, and to a lesser extent Corminaty from Biontech / Pfizer. This is indicated by several studies, such as a work from Israel published in the “New England Journal of Medicine”, reports from the Canadian health authority Public Health Ontario and a not yet published “Nordic study” from Scandinavia.

The Reuters news agency quotes Mika Salminen, director of the Finnish Health Institute, with the statement that the “Nordic Study” has shown that men under 30 who have been vaccinated with Spikevax have a slightly increased risk of myocarditis. The study should be published in a few weeks and is already available to the European Medicines Agency Ema.

Corona vaccination: Iceland suspends use of Moderna vaccine

Iceland justifies the preliminary complete suspension of the Moderna vaccine with an overall observed increase in the incidence of myocarditis and pericarditis (inflammation of the pericardium). In Iceland, people vaccinated with the Johnson & Johnson * single-dose vaccine received an additional dose of the Moderna vaccine only.

(The background is the apparently inadequate protection of the Johnson & Johnson vaccine against the Delta variant, which is why the German Standing Vaccination Commission now recommends a second vaccination with an mRNA vaccine.) In addition, older and immunocompromised people in Iceland had a booster vaccination Obtained Spikevax from Moderna.

In the video: WHO considers the connection between mRNA vaccination and myocardial inflammation to be “likely”

The already available reports from Israel and Canada come to the conclusion that heart muscle inflammation after a Covid vaccination with an mRNA vaccine occurs very rarely, but is much more frequent than would normally be expected. In most cases, around 70 percent, the complication occurred within a few days of the second dose.

Corona vaccination: Heart muscle inflammation occurs more frequently than normally expected

There is also agreement that young people in particular are affected, male adolescents and young men far more severely (they make up around 80 percent of cases) than girls and young women. However, the reasons for this gender inequality are not yet known.

In the Israeli study, most cases occurred in the 16 to 19 age group, while the 18 to 24 year olds were most at risk in the report from Canada. However, the two studies can only be compared to a limited extent, as only the vaccine from Biontech / Pfizer was used in Israel. In the Canadian work, the myocarditis risks according to Corminaty and Spikevax are compared.

The Public Health Ontario report for the period from December 13, 2020 to August 7, 2021 recorded 263.2 cases per one in the most affected age group of 18 to 24 year olds for the vaccine from Moderna after the second dose Million cans. At Biontech / Pfizer, there are 37.4 cases per million doses.

Heart muscle inflammation after corona vaccination: “More than twice the risk”

For the study from Israel with the title “Myocarditis after BNT162b2 mRNA Vaccine against Covid-19”, the period from December 2020 to May 2021 was considered, in which around five million were vaccinated there. The Israeli Ministry of Health recorded 136 cases of “definitive or probable myocarditis” that occurred close to the vaccination. That is a “more than twice as high a risk as in unvaccinated people”.

About 1 in 6,637 male vaccinated and 1 in 99,853 female vaccinated between the ages of 16 and 19 would have “sure or likely” developed myocarditis within 21 days of the second vaccination. In three out of four cases, the heart muscle inflammation is said to have been mild.

With myocarditis after Covid-19 vaccination mostly mild courses

Why the vaccine from Moderna leads to heart muscle inflammation to a greater extent than that from Biontech / Pfizer can be guessed, but not yet proven: Spikevax contains 100 micrograms of mRNA per dose, Corminaty 30 micrograms. Because the composition of both vaccines is not identical, it is not so easy to compare – even if the assumption that it has something to do with the amount is obvious.