Suspected of causing rare cases of thrombosis, the AstraZeneca and Janssen vaccines are not favored by the general public, who prefer messenger RNA sera.
Today, almost everyone wants to receive the vaccines from Pfizer-BioNTech or Moderna, considered safer and more effective, and more easily adaptable to the Brazilian and South African variants.
Does this mean that vaccines based on more traditional technologies no longer have their place in the French vaccine strategy?
When is the next world?
When will the terraces, the trips, the kiss, the hugs and the end of the mask?
"Patience" and "efforts", tells us the government, which promises the beginning of a return to normal life from the month of May.
The key to a daily life without Covid-19, the health authorities hammer it home, is vaccination, the general opening of which to over 18s is scheduled this summer.
But with which vaccines and for what effectiveness?
The risks of thrombosis associated with the AstraZeneca and Janssen vaccines have cooled some of the eligible populations, who today shun these sera.
And in the face of the Brazilian, South African, Indian and other recombinant variants that locally cause new epidemic outbreaks and can affect the effectiveness of vaccines, the light at the end of the tunnel seems to keep receding.
In this viral storm, the “messenger RNA vessel” does not rock.
And today, almost everyone wants to be vaccinated with Pfizer or Moderna, with relentless prowess.
But are there only these messenger RNA (mRNA) vaccines to get us out of the deadlock, or do the other sera retain a prominent place (and a usefulness) in the French vaccine strategy?
Messenger RNA vaccines with multiple advantages
From the start, the French vaccine supply has gone through Europe. After options posed on different vaccines and a few weeks of hindsight, at the EU summit, we had time to form an opinion and think about the next orders. Delivery delays (for AstraZeneca), side effects and popular distrust (for AstraZeneca and Janssen), risks of immune escape (for AstraZeneca): by reviewing the different vaccines, but also by anticipating a possible spread of variants - Brazilian and South African - more contagious, some vaccines have lost their appeal, with AstraZeneca in the lead.
So, “to resolutely defeat the virus, we will have to be ready, at some point, to give boosters to strengthen and prolong immunity. And if resistant variants appear, we will have to develop suitable vaccines, ”recalled Ursula Von Der Leyen, President of the European Commission, on April 13. For the head of the community executive, the solution is clear: it is necessary to rely on "technologies which have proved their worth, which is the case with mRNA vaccines". Namely Pfizer-BioNTech and Moderna, the two mRNA sera available to date, which will soon be joined by the German Curevac. Thus, if "the decision is not taken", "the greatest probability" is that Europe will not place new orders for AstraZeneca, declared the French Minister of Industry,Agnès Pannier-Runacher, a few days ago.
At the same time, fear is growing around the Brazilian and South African variants. "They are of concern because they cause an immune escape, that is to say they reduce the protective immune response induced by vaccination," explains Daniel Floret, vice-president of the Technical Commission for Vaccinations of the High Authority. health (HAS). AstraZeneca is shown to be less protective here. And what we know is that the two mRNA vaccines retain good efficacy against these more virulent variants. Probably a little worse than the English variant and the initial strain, but still very satisfactory. And they have the advantage of being more quickly adaptable to new variants: it is much easier with mRNA vaccines to update the formulations,continues the vaccination specialist. The companies are already working on mRNA vaccines that integrate the new variants, whether monovalent sera, which target only these variants, or bivalent sera, both against the initial strains and the new variants ”.
The other vaccines remain "essential"
Result: mRNAs are popular with the general public, who want to receive Pfizer and Moderna.
However, anti-Covid vaccines developed according to more classic formulations - with a viral vector - should not be discarded.
“Today in France, it is the English variant which is dominant, it represents more than 85% of infections.
And against him, Pfizer, Moderna, but also AstraZeneca and Janssen are effective, ”recalls Daniel Floret, who stresses that it is“ also possible to adapt the formulations of viral vector vaccines to new variants ”.
To date, “the South African and Brazilian variants represent barely 5 to 6% of contaminations,” he reassures. Moreover, the Janssen vaccine, with a viral vector, shows real effectiveness against variants ”. But if they circulate relatively little in France, "there is the particular case of Alsace - where the South African variant represents more than 20% of contaminations - and of the overseas departments", recognizes Daniel. Floret. Thus, “in Guyana [Brazilian variant], Mayotte and Reunion, where the South African variant represents almost half of the cases and where the supply of a single type of vaccine is favored by logistical constraints, the HAS recommends the continuation of the strategy already in place with the exclusive use of mRNA vaccines ”, prescribed the HAS.
Outside these territories, the HAS considers that "this does not justify setting up, at this stage, a differentiated strategy for the use of vaccines". As for AstraZeneca, "if we were not to use the doses we have, it would be difficult to achieve the objectives in terms of vaccinated population, advance Daniel Floret. For now, they are still absolutely necessary ”. The AstraZeneca and Janssen vaccines are even considered "essential" to achieve the goals of the vaccination campaign, said Tuesday the Ministry of Health, although it is more difficult today to find volunteers to receive two doses. On the other hand, warns Daniel Floret, if the Brazilian and South African variants "exceeded 20% of the contaminations over a certain period of time,the administration of mRNA vaccine should probably be generalized ”.
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