Orange with Media Services, published on Sunday, June 12, 2022 at 3:34 p.m.
Pfizer/BioNTech and Moderna each announced at the end of 2021, research for the development of vaccines adapted to the Omicron variant. This considerably reduces the effectiveness of currently available vaccines, due to its genetic profile.
Moderna has just announced “positive” results from its bivalent vaccine against Covid.
While at the start of the school year, a new campaign of booster doses of vaccines against Covid is looming at least for the elderly and those at risk, will it be carried out with vaccines adapted to Omicron? The challenge is of course that of protection: Omicron considerably reduces the effectiveness of currently available vaccines, due to its genetic profile.
To obtain better efficacy than those of the original messenger RNA vaccines, there are therefore two options: either the development of versions adapted to the Omicron variant, or either vaccines from other manufacturers (Sanofi, Valneva, etc.) and using different techniques.
Pfizer/BioNTech and Moderna have chosen to work on a new version based on both the original strain of SARS-CoV-2 but also on Omicron. The two messenger RNA manufacturers had initially planned to complete in the spring or early summer. “If all goes well, we could make it available to the public during the summer”, indicated on January 2 in The Express Moderna Vice President Dan Staner. Uncertainties remain about their availability at the start of the next school year, but also about their effectiveness.
Race against the clock with the arrival of new variants
Clinical trials were launched at the beginning of the year. No scientific article to date, although Moderna published preliminary results in a press release this Wednesday, June 8. A booster dose of its “bivalent” vaccine would make it possible to multiply by approximately two the titers of neutralizing antibodies against Omicron, after one month, compared to a “booster” of its currently available vaccine.
“These are data of antibodies in the blood and not vaccine protection. The amount of antibodies decreases over time but, even after a booster, it can be assumed that the protection will last longer”, comments to the Parisian Prof. Olivier Schwartz, director of the Virus and Immunity Unit at the Institut Pasteur. “A factor of 2 is far from gigantic. The only thing we can say is that the higher we start, the slower the descent”, adds immunologist Stéphane Paul.
But these data stop at the first month. It is therefore impossible to predict how long the protection could persist at a high level, both against infection and against severe forms. The emergence of new variants within the Omicron family, BA.4 and BA.5, also raises uncertainties. Signs raise fears of an epidemic resumption, perhaps as early as this summer in France. BA.4 and BA.5 possess several different mutations compared to their predecessors.
Could the results already obtained by Moderna therefore be called into question? The medical director France at Moderna wants to be reassuring: “Because of the superiority displayed, we anticipate a response adapted to all the sub-lineages of Omicron”, replies Arnaud Chéret.
As for Pfizer/BioNTech, clinical trials are still ongoing and initial data could be announced by the end of June. It is the health agencies that will decide to authorize or refuse these new products.
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