Booster dose: why is the Moderna vaccine so suspicious? – actu.fr

We are in the middle of the fifth wave of Covid-19. In France, since the start of the epidemic in January 2020, the virus has killed around 120,000 people.

In an attempt to counter its spread, various world governments have launched several vaccines. A third so-called “booster” dose has just been open to all by the French executive.

For the latter, the French have the choice between the two messenger RNA vaccines: Moderna or Pfizer. And the first is much less popular: “only” 11,418,700 injections between the start of the vaccination campaign and November 25, 2021 against 83,735,200 for Pfizer over the same periods.

Pfizer widely acclaimed

“It is common for patients who had made an appointment to cancel when they are told that it will be Moderna”, laments a Breton pharmacist.

“This can be explained by an erroneous perception, on the one hand because of the very great notoriety of the Pfizer vaccine, on the other hand, by the very brief temporary suspension of Moderna in October. In addition, many people were vaccinated with Pfizer in the spring and this summer ”, indicates the General Directorate of Health (DGS), contacted by actu.fr.

Is there one better than the other?

He is difficult to determine one vaccine better than the other. Corn, a very recent study conducted by American researchers working in the Harvard and Boston units looked into the question.

On a sample of approximately 440,000 veterans of the United States Army, who received their two doses of vaccine, between January 4 and 1^er July 2021 two groups were formed. Those vaccinated at Moderna, and those at Pfizer.

The figures from this study are clear: Moderna advantage. Whether in terms of virus infections, asymptomatic forms, hospitalization, admission to intensive care, and even death. Each time, the figure is lower among those vaccinated with Moderna, even if the difference is relatively small.

For example, reduced to a scale of 1,000 people, the study found 5.75 Covid-19 contaminations in those vaccinated with Pfizer against 4.52 for Moderna. Ditto for deaths: 0.22 at Pfizer, and 0.20 at Moderna.

In a study involving nearly 440,000 veterans, both the BNT162b2 and the mRNA-1273 vaccines were highly effective at preventing infection, hospitalization, and death from # COVID19. https://t.co/nEpFWy1dwr pic.twitter.com/0JHnvS3y7k

– NEJM (@NEJM) December 1, 2021

However, this study has limitations. For example, the fact that “our study population was mainly composed of men (93%) and the elderly (90% were over 50), which may limit the generalization of our results”, such as explain the researchers.

A history of cardiac complication?

In France, in an opinion issued on November 8, 2021, the High Authority for Health (HAS), relying on a flagship Epi study, believes that Pfizer “has a lower risk of myocarditis, and pericarditis, heart complications, especially in people under 30. ”

We are talking about “131.6 per million cases for Moderna against 26.7 for Pfizer” in people under 30 years of age. Men are, moreover, more affected by this side effect. The HAS therefore recommends the Pfizer vaccine for those under 30 years of age.

It is for this reason that the Moderna vaccine was briefly suspended in October.

“In people over 30, this side effect is even rarer,” reassures the Brittany Regional Health Agency, contacted by actu.fr.

This is explained by the higher RNA dosage at Moderna during the primary vaccinations: “It was administered at 100 μg of RNA per dose, whereas the Pfizer, 30 μg”, specifies the DGS.

On this subject, Professor Alain Fischer, quoted by the DGS, wishes to reassure: “It should especially not be deduced from this that this vaccine would involve any particular danger for people over the age of 30 in the current context. It is quite possible to receive a Moderna reminder without any problem and it is not necessary absolutely not refuse this opportunity. “

In addition, “some countries do not apply the precautionary principle aiming to vaccinate those under 30 with Pfizer. This is the case in the United States in particular, ”points out the ARS.

Anything to do with side effects?

“We, what we observed in our pharmacy, is that people who were vaccinated with Moderna reacted more. They complained of red patches, fever or joint pain, ”says the pharmacist we contacted.

Facts corroborated by the National Agency for Medicines and Health Products Safety (ANSM), which is based on figures dating from November 25, 2021: 83,735,200 Pfizer injections have been carried out since the start of the vaccination campaign for 71,624 observed adverse cases.

Regarding Moderna, we are at 11,418,700 injections since the start of the campaign for 15,559 undesirable cases, ie 0.09% for Pfizer and 0.14% for Moderna.

However, as part of a vaccine booster, it is half a dose of Moderna which is injected, and not plus a full dose as for the first two bites. It is the HAS which recommends it, and this has the effect of significantly bringing together the weights: 50 µg at Moderna and 30 at Pfizer.

A decision based on the opinion delivered by the European Medicines Agency.

“I think the side effects were related to the fact that Moderna is stronger, more dosed. By cutting the dose in half, we rule out this problem, ”notes the pharmacist.

Moreover, “the adverse effects of vaccination against Covid are rare and not very specific. Most often, these are the effects linked to the stimulation of the immune system (fever, body aches, etc.) or linked to the apprehension of the vaccination act ”, tempers the ARS.

Scandals that weigh heavily in the balance

The pharmacist we contacted has another idea. For her, the general public has made up its own mind via the various scandals that have punctuated the vaccination campaign. Moderna was briefly suspended in October, suspected of causing complications such as pericarditis or myocardia.

And even before that, over 1.6 million doses of Moderna were recalled in Japan because they contained steel and plastic particles, which fell into the tubes during production or transportation.

According to the survey conducted by Moderna, these impurities had no consequences on health. But the damage was done.

And the Frenchman who hears that, if he makes the link with the October suspension, and if he is already not too much in agreement with the fact of being vaccinated, his opinion is greatly influenced by it.

However, the various studies are formal. There are very few differences in results between Moderna and Pfizer. Minister of Health Olivier Véran said it very well at the microphone of France Info, Friday December 3:

I insist: Moderna and Pfizer, it’s the same. The only difference is that if you are under 30, we prefer to give you Pfizer and it is not for reasons of effectiveness.

The DGS agrees: “We recall that the two RNA vaccines have a excellent safety profile and comparable efficiency. And they are also perfectly interchangeable for the recall, as emphasized by all health authorities. “

Ditto for the ARS: “the available studies show that the two vaccines have a comparable effectiveness of the order of 94% to 95%. “

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