Credit ACIP/CDC
#17,270
Although most vaccines - including the COVID mRNA vaccines - have an enviable safety record, it is worth repeating that there is no such thing as a 100% safe drug or medication for 100% of the population.
Even over-the-counter medications like NSAIDs or acetaminophen, can sometimes produce adverse - even fatal - reactions (see BMJ Research: NSAIDs & The Risk Of Heart Failure).
While the value of the mRNA COVID vaccines in those who are older, or who have comorbidities, has been well demonstrated, many people remain leery of using these vaccines in younger people - particularly adolescent males - due to reports of (usually mild) Myocardititis in some recipients (see CDC Clinical Considerations : Myocarditis & Pericarditis after Receipt of mRNA COVID-19 Vaccines Among Adolescents and Young Adults).
At the same time, Myocardititis is a known complication of COVID infection (see Heart disease after COVID: what the data say).
While this might seem like a damned if you do, and damned if you don't decision, we've seen studies showing that vaccine-induced myocarditis is generally milder than viral-induced myocarditis, and most people fully recover in 90 days or less.
Another study - Myocarditis in SARS-CoV-2 infection vs. COVID-19 vaccination: A systematic review and meta-analysis - found that that infection with the SARS-CoV-2 virus is 7 times more likely to cause myocarditis than receipt of the vaccine.
Today we've another multi-country study, recently published in the BMJ, that also finds that vaccine induced myocarditis is less severe than after viral infection.
This (translated) summary from Denmark's SSI.
Myocarditis after covid-19 vaccines is less severe than after viral infections
If you get inflammation of the heart muscle shortly after a covid-19 vaccination, the course is less serious than if you get the inflammation from, for example, a covid-19 infection. This is shown by a new large Nordic study.Last edited on February 2, 2023
Researchers at the Statens Serum Institut (SSI) have, together with colleagues from Sweden, Norway and Finland, examined how patients with inflammation of the heart muscle fare, depending on whether the disease occurred after vaccination or after infection.
The Covid-19 vaccines, which are based on the mRNA technology, can in rare cases cause inflammation of the heart muscle. Inflammation of the heart muscle is a rare but known phenomenon after primarily viral infections. It occurs most often in young and healthy men. The symptoms can be shortness of breath and chest pain. Most cases go away on their own, but in some serious cases the myocarditis can lead to heart failure. Fortunately, everything now suggests that cases that occur after a vaccination are milder than myocarditis after an infection.
Data from 7,292 patients have been examined
The new joint Nordic study included all cases of inflammation of the heart muscle in Denmark, Norway, Sweden and Finland in the period 2018 to 2022. It concerned 7,292 cases, of which 530 had occurred shortly after vaccination, 109 had occurred shortly after covid-19 infection and the remaining 6,653 had most likely occurred after other viral infections.
The researchers followed the patients for 90 days after they had been diagnosed in a hospital and investigated whether there was a connection between the suspected cause of the myocarditis and the risk of being readmitted to the hospital, of having heart failure or of dying.
Cases that occurred after vaccination were milder
The researchers found that patients with myocarditis that had developed shortly after vaccination were 21%, 44% and 52% less likely to be readmitted, to have heart failure and to die, respectively, than patients who had contracted the disease from another cause.
In 12- to 39-year-olds who were otherwise healthy and fit before they were affected by myocarditis, the risk of heart failure or death if you had contracted the disease in connection with covid-19 instead of after vaccination was 6 times increased.
"Our results are reassuring and point in the direction of a milder form of myocarditis after vaccination than the type of myocarditis that normally occurs. If we compare directly with covid-19 infection, there is a big difference in the degree of severity. We observed a significant increase in the risk of heart failure and death for the cases that occurred after covid-19 infection compared to the cases that occurred after vaccination," says Professor Anders Hviid, head of department at SSI, who is one of the researchers behind the study.
The study has just been published in the prestigious medical journal BMJ Medicine: " Clinical outcomes of myocarditis after SARS-CoV-2 mRNA vaccination in four Nordic countries: population based cohort study "
While I don't expect these types of studies to change the minds of those who are vehemently anti-vaccine, they may provide a bit of reassurance to those who have made the decision to have their kids vaccinated.
