Tuesday, September 28, 2021


The study, in prepublication, conducted by American researchers and relayed by our colleagues from the World reports a still high level of protection of vaccines against the different strains of the coronavirus.
These are preliminary results that question. A team of researchers from the American University Hospital and Research Federation Mayo Clinic has unveiled a study on the effectiveness of messenger RNA vaccines – Pfizer-BioNTech and Moderna – against the two major variants of Covid-19.

Published on August 9 on the MedRxiv prepublication platform, this work has established that the two messenger RNA vaccines are highly effective – but despite everything different depending on the situation – against the two main strains of the coronavirus: the Alpha variants (known as ” British “) and Delta (Indian).

As a reminder: the effectiveness of the main vaccines currently distributed around the world to fight the Covid-19 pandemic lies above all in the prevention against severe forms of the disease. If it is now established that they can limit the transmission of the virus between individuals, they make it possible above all to reduce the risk of hospitalization.

Pfizer vaccine 42% effective against Delta variant infection
Important clarification: if these data were collected in the US state of Minnesota on nearly 50,000 people (half vaccinated and the other unvaccinated) between January and July 2021, they still need to be confirmed so that the study will be published in a scientific journal.

According to the researchers’ results, with regard to the Alpha variant, the Pfizer vaccine reduces the risk of hospitalization by 85%, that of Moderna by 91.6%. Their effectiveness against infection, and therefore the potential transmission of this same variant, drops slightly: 76% for the Pfizer vaccine and 86% for Moderna.

This difference is more marked compared to the Delta variant, now the majority in France and circulating more and more around the globe. The Pfizer vaccine is still effective here against the risk of hospitalization (75%) even if it is slightly less than the Moderna vaccine (76%). It is on the risk of infection that the difference is very important: the Moderna vaccine is here 76% effective against infection while the Pfizer / BioNTech vaccine is only effective at “only” “42%.

A person holds a vial of Moderna Covid-19 vaccine on June 29, 2021 in Quimper, western France (Photo by Fred TANNEAU / AFP) (Photo by FRED TANNEAU/AFP via Getty Images)

By far the most injected Pfizer vaccine in France
To support their point, the authors of the study refer to the results carried out by another team of researchers in Florida, the new epicenter of the epidemic in the United States.

“The risk of infection in July with a full vaccination with Moderna is approximately 60% lower than after a full vaccination with Pfizer”; they continue.
If Pfizer and BioNTech announced in early August that it is “not yet” necessary to adapt their vaccine to variants – its effectiveness being established – the two founders of the German biotech assured Les Échos last July that they will be willing to develop and produce a new vaccine suitable for resistant strains “within a hundred days”.

LONDON, UNITED KINGDOM – 2021/06/05: A Covid-19 vaccinator administers the Oxford/AstraZeneca vaccine to a woman at a vaccination centre in London. (Photo by Dinendra Haria/SOPA Images/LightRocket via Getty Images)

In France, the vaccine from Pfizer and BioNTech is by far the most widely distributed with more than 63 million doses injected out of some 80 million administered to the French population, according to the specialized site Vaccine Tracker. In comparison, nearly 7.9 million doses of the Moderna vaccine were administered. According to figures communicated by the Ministry of Health on Saturday evening, 46,267,777 French people have received at least one dose of vaccine against Covid-19 – or about 68.6% of the population – and 39,028,100 (57.9% % of the population) have a complete vaccination schedule.

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