Vaccines against Covid-19: clinical data lacking… were the new serums adapted to Omicron approved too soon?

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Bivalent vaccines, effective against variants of the Omicron family, will soon be offered in France as part of a new vaccination campaign against Covid-19. However, there are no clinical data on their efficacy in humans.

Almost a year after the discovery of Omicron in South Africa, vaccines adapted to the BA.1 and BA.5 variants will soon be available in France. Bivalent vaccines, developed by Pfizer / BioNTech and Moderna, will be the subject of a special campaign in France from October 3. “Fragile people, the over 60s, health professionals and people who are in contact with fragile people” will be eligible for this new campaign, announced François Braun, Minister of Health.

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Covid-19: reminder, effectiveness… in France, what will the arrival of new bivalent vaccines adapted to Omicron change?

Within the scientific community, however, these vaccines are far from reaching consensus: before any marketing authorization, the Pfizer / BioNTech laboratories did not share clinical data to demonstrate their effectiveness on humans. “The agencies could have demanded clinical trials, but preferred to go quickly, taking a risky bet for the capital of public confidence if it turned out that these vaccines were less effective than monovalents”, thus disputes on social networks epidemiologist Antoine Flahault, echoing the words of Agence France Presse.

2/9 – There is a great deal of confusion in the public and the media over the vaccine recalls of the #COVID19. The EMA and the FDA have bypassed the usual steps for approving a vaccine. The antivax are having a blast, they couldn’t dream of a better blessed bread.

— Antoine FLAHAULT (@FLAHAULT) September 23, 2022

Efficiency. This is the sinews of war for these newcomers to the vaccine landscape. The vaccines that are used today to fight against Covid-19 provide effective protection against serious forms of the disease… but not to stop the mechanisms of infection. Will the new vaccines make it possible to fight against contamination? Will they be more effective in preventing any serious form of the disease? Impossible to know: “The rapid way in which the development of bivalent vaccines has been carried out does not allow us to know today whether they are more effective or not”, Antoine Flahaut further affirms to The Midi Dispatch.

“The antivax are having a field day”

Can a vaccine therefore benefit from a marketing authorization without having these data? The practice is common in the pharmaceutical industry, particularly for vaccines against influenza and rare diseases: “In the first case, manufacturers simply do not have the time to conduct clinical trials for their vaccine candidate and in the second, there are not enough patients to carry out these trials, comments Antoine Flahault. But Covid-19 is not the flu… We could therefore have required manufacturers to conduct traditional clinical trials.

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The risk ? Deconstruct the legitimacy of these new vaccines and sow discord in a public that is already struggling to understand and accept the recommendations made by health authorities. “There is great confusion in the public and the media about the Covid-19 vaccine recalls, continues the epidemiologist on social networks. .”

Nothing, however, that could jeopardize their safety: “There are data that have been collected from clinical trials conducted on volunteers, explains the professor. We therefore have no concerns about the tolerance of these vaccines.”

What are these new effective vaccines against Omicron?

Earlier this month, the Haute Autorité de Santé approved three bivalent vaccines. Two of these vaccines, developed by Pfizer / BioNTech and Moderna, are effective against the BA.1 strain, which hit France at the end of 2021. A third vaccine, again designed by Pfizer / BioNTech, has been approved by HAS: this is adapted to the BA.4 and BA.5 variants, which currently affect France. These three vaccines had already been approved by the European Medicines Agency.

“The evaluation of the efficacy of the bivalent vaccine targeting the BA.5 sub-variant of Omicron only focused on trials in mice, explains Antoine Flahault. Concerning the bivalent vaccines targeting the BA.1 sub-variant of Omicron, it related to human clinical data, but they concern so-called ‘surrogate’ criteria”.

A nurse prepares a vaccine against Covid-19, in Toulouse on December 9, 2021.

A nurse prepares a vaccine against Covid-19, in Toulouse on December 9, 2021.

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