“We do not have enough perspective”, “we refuse to be guinea pigs” … Among opponents of vaccination against Covid-19, a fear often arises: serious adverse effects (chronic disease, cancer, infertility) could be discovered years after the
messenger RNA vaccine (Pfizer-BioNTech and Moderna)… A proven risk or an unfounded distrust?
Mild side effects with messenger RNA
First of all, it is true that messenger RNA vaccines can cause unwanted effects. The main ones are mild and usually occur within forty-eight hours after the injection: fever, tremors, headaches, etc. However, after the Moderna vaccine, theNational Medicines Safety Agency (ANSM) identified cases of pain and redness at the injection site occurring between 4 and 31 days after vaccination (with an average delay of 8 days).
Despite everything, pharmacovigilance has highlighted a link between these vaccines and the appearance of two pathologies: myocarditis and hypertension. According to the ANSM, there had been in France, between the start of the vaccination campaign and July 8, 64 cases of
myocarditis and 111 of
pericarditis for Pfizer (out of 45.7 million injections) and 7 myocarditis and 13 pericarditis for Moderna (5.5 million doses). All of these patients recovered. As for hypertension, it affected 729 French people vaccinated by Pfizer and 58 by Moderna.
Posted August 26, ” an israeli study in 2 million people has shown that people vaccinated with messenger RNA have 3.5 times more risk of having myocarditis (especially young men and after the 2nd dose), 1.4 times more risk of making a
shingles and 2.4 times more to have lymph nodes (and 1.4 appendicitis) than the unvaccinated ”, explains Odile Launay, infectious disease specialist and member of the
Covid-19 vaccine scientific committee. Discoveries which do not however call into question the benefit / risk balance of these vaccines: these problems remain rare and the dangers of Covid-19 far exceed them. Thus, the risk of developing myocarditis is multiplied by 18 by the coronavirus …
Fundamental clarification: these side effects occur very quickly. “Anaphylactic shock is in the first fifteen minutes and, for myocarditis, within fourteen days”, specifies Sandrine Sarrazin, researcher in immunology at theInserm. A delay that sticks with what we know about other vaccines.
Scandals denied
“In the history of vaccination, we have never seen adverse effects at a distance from vaccination,” insists Odile Launay. Above all, some vaccine scandals have turned out to be unfounded.
In 1998, a study published in The Lancet suggested a link between MMR vaccine (measles, mumps, rubella) and autism. After dozens of studies contradicting this thesis, the prestigious journal admits its error in 2010: the data was skewed. “The article was retracted, but the false news persisted, regrets
Mathieu Molimard, head of pharmacology at the Bordeaux University Hospital. In the 1990s, there was talk of a possible link between the hepatitis B vaccine and multiple sclerosis. But we have no evidence of the causal link, it is clear now. Likewise for the presence of aluminum and the appearance of pathologies, again, this is fake news. “
The problem is that once the doubt is instilled, it is difficult to restore confidence. Because it sometimes takes decades for studies to deny the accusations. Thus, in 2019, a large study ensures that the vaccine does not cause multiple sclerosis… And that on the contrary, some would protect against this autoimmune disease. “Doctors have not communicated enough on this issue, regrets Sandrine Sarrazin. You can drive into a tree after being vaccinated, but it’s not because of the serum! “
That’s the whole difficulty: knowing what is attributable to the vaccine or just a coincidence. “To establish whether an event is linked to the vaccine or not, we look at the statistics of occurrence of this disease among the vaccinated and unvaccinated population,” continues the researcher. To go further, it is necessary to carry out specific clinical trials and therefore to have a follow-up of each undesirable effect. “
Proven causalities, but rapid symptoms
Second important information: it has happened that some “scandals” have been confirmed by studies, but the diseases caused always appear in the first months after the injection. So the Guillain-Barré syndrome, whose severe cases can lead to paralysis, has been identified in people vaccinated against the H1N1 virus and more recently
against Covid-19, but only with AstraZeneca. “For AstraZeneca, symptoms occur within 10 to 22 days, for H1N1, it is before 42 days,” explains Sandrine Sarrazin.
Why did some effects take years to be identified? The Vidal displays a delay of about four months for the onset of narcolepsy after the
Pandemrix (which is no longer prescribed) against H1N1 … “All the adverse effects of vaccines appear within two months after the injection,” insists Mathieu Molimard. This does not mean that they were identified within this timeframe! This is where some play on the ambiguity. For example, for narcolepsy, symptoms always appear within three weeks of vaccination. But, to make the diagnosis, examinations with electrodes on the head are needed in a center specializing in sleep. And it is three months of delay. “
Messenger RNA disappears quickly
Third explanation that reassures researchers and doctors: chemistry shows that a reaction can occur only in the days following the injection. The messenger RNA vaccine is made up of two parts: a lipid capsule that carries a strand of RNA. Both are eliminated within a few hours by our body. “The RNA molecule is very fragile,” continues Sandrine Sarrazin. It’s like a self-destructing photocopy. Unlike DNA, which can be found in Paleolithic caves. ” Gold, Inserm reminds us in this article, “In any case, the injected RNA does not penetrate into the nucleus of the cells where the genetic material is located. “.
In addition, the vaccine is injected intramuscularly and “as the RNA molecule is not mobile, it will remain in the muscle”, continues the researcher. No risk, therefore that this messenger RNA is found in the ovaries … If infertility is an argument advanced by some antivax, “there is no theoretical element, nor data of toxicity in animals which would suggest an impact on fertility for these vaccines as for all the others, ”insists Odile Launay.
Reinforced surveillance in times of pandemic
Finally, fourth aspect, this time, exceptional: the “advantage”, with a pandemic of the magnitude of the coronavirus, is that the data is plethora. With billions of people vaccinated around the world, eight months of decline, reluctance and tangible criticism, pharmacovigilance has never been so meticulous. There is therefore little risk of disturbing signals being passed under the radars …
The proof: very quickly, the reports of thrombosis linked to the AstraZeneca vaccine were raised, studied and several countries suspended or limited its access. “With highly developed monitoring methods, computer tools that allow real-time reporting, we can be sure to be exhaustive about adverse effects,” insists Odile Launay. That does not mean that we should not continue to monitor! But the concern today is the risk that certain variants will defeat the vaccination, much more than the safety of these vaccines. “