Thus a study on pericarditis confirms the safety of anti-Covid vaccines

An interesting work carried out by Canadian researchers has just been published, who studied the risk of myopericarditis in subjects vaccinated with RNA vaccines against SARS-CoV-2. Starting from the data obtained after 10 million doses, hospitalization or the need for emergency therapy for this cause was studied within 7 and 21 days of vaccination. We found 179 incident cases of myopericarditis within 7 days and 308 cases within 21 days after vaccination. Overall, the rate of myopericarditis in the vaccine cohort was 1.75 (95% CI 1.50-2.02) per 100,000 mRNA vaccine doses within 7 days, with an observed-to-expected event ratio of 5. 18 (95% CI 4.45-5.99). At 21 days, there were 3.00 events (95% CI 2.68-3.36) per 100,000 doses, with an observed/expected ratio of 2.97 (95% CI 2.65-3.32). Based on gender, vaccine type, and number of doses, the rates per 100,000 doses and observed/expected ratio were higher among males, among mRNA-1273 recipients, and after the second dose of mRNA vaccine.

If the inoculated subjects are differentiated by age, the highest rate per 100,000 doses is observed among subjects aged between 18 and 29 years, while the highest ratio between observed and expected events was found for subjects aged between 12 and 17 years old. Looking at other variables that differentiate the subjects studied, it is also found that myopericarditis is higher especially after the second dose, among those who received the mRNA-1273 vaccine (Moderna) and finally among males. The highest rates of myocarditis were seen after the second dose of the vaccine among 18- to 29-year-old males. In this subgroup, rates were approximately four times higher with the mRNA-1273 vaccine than with the BNT162b2 vaccine (Pfizer-BioNTech). Myocarditis rates were lower after the third dose of vaccine than after the second dose.

Now, how are we to look at these numbers? In other words, how to translate these quantitative measures, which demonstrate a more or less accentuated increase in the risk for certain heart conditions for subjects who are vaccinated with RNA-based products, into an evaluation that tells us whether or not it is advisable to get vaccinated, once the safety level of vaccines according to the numbers provided? First of all, I would like to insist precisely on the final words of this question: for each treatment, whether we are talking about vaccine, drug, massage or bua basin, safety is not evaluated in a dichotomous way, i.e. establishing that something is absolutely risk-free or not it is. Instead, the level of safety is evaluated, i.e. how safe a product is, in the way done by the authors, i.e. through the quantification of measurable risks.

In the light of the results obtained, the researchers who published the study in question are keen to reassure us, right from the first lines of the work, writing in fact: “Ultimately, our results show the overall safety of the mRNA vaccine. Overall myocarditis rates per 100,000 doses were still very low for both vaccines”. And why is safety considered sufficient to recommend vaccination? Because, as the authors always report, the number of adverse events caused by the virus, avoided thanks to vaccines in the pandemic period considered, is much higher.

Reporting published US data, they show for example that “560 hospital admissions, 138 ICU admissions, and 6 deaths from COVID-19 could be prevented per million second doses of SARS-CoV-2 mRNA vaccine given to males aged 12-29, compared with 39- 47 expected cases of myocarditis after SARS-CoV-2 vaccination”. That is to say that in the range most at risk of adverse events from RNA vaccines, hospitalizations and intensive care caused by the virus are over an order of magnitude more numerous than vaccine myocarditis (which, moreover, is almost always resolved in a benign way ); this without even counting the dead.

Now, it is clear that any improvement in the safety of current products will be welcome, if it can further reduce the rare cardiac effects of vaccination.; if the causal mechanisms are clarified, this may well be possible. However, if this happens, it will be an improvement of products that are already very safe and for which the risk/benefit ratio is currently very favourable, taking into consideration a certain type of risk following the spread of the virus and vaccination (and not a inhomogeneous cauldron of any side effect, however slight).

Researchers around the world are working to improve the efficacy against new variants and infection and safety of the products we have; but the fact that a product can be improved does not mean that the current safety or efficacy has been insufficient, but rather testifies to the progress that derives from continuous knowledge. If a new technology were developed that could make cars safer, we wouldn’t accuse the manufacturers of today’s cars of having sold us unsafe products; in the same way, today’s vaccines have been well above the threshold of the risk/benefit ratio, and have avoided millions of deaths and unnecessary hospitalizations in the world, despite the fact that some undersecretaries find it difficult to convince themselves of this.