A French study conducted on a panel of 22 million people confirms that the vaccination greatly reduces the risk of severe Covid. This study is “the largest in the world,” according to epidemiologist Professor Mahmoud Zureik.
Epi-Phare researchers compared the data of 11 million vaccinated people over the age of 50 with that of 11 million unvaccinated people in the same age group, from the start of the vaccination campaign in France on December 27, 2020, to July 20, 2021.
The results show the Covid vaccination reduced the risk of hospitalization and death by 90% for people in their fifties, and also seemed effective against the Delta variant.
“Vaccinated people are 9 times less likely to be hospitalized or die from Covid-19 than unvaccinated people,” said Professor Zureik, director of the Epi-Phare structure, which brings together the Caisse nationale de l'Assurance Maladie and the Agence nationale de sécurité du médicament.
This data is valid for those of Pfizer/BioNtech, Moderna and AstraZeneca (Janssen, authorized later and used in smaller proportions, was not included in the study) and confirms observations made in other countries, including Israel, the U.K. and the U.S.
From the 14th day after the injection of the second dose, researchers observed “a reduction in the risk of hospitalization greater than 90%.” They found results comparable to previous periods: an efficiency of 84% in those 75 and over, and 92% in those 50-74. “The study must be continued to integrate data for August and September,” Professor Zureik stated.
The study has two parts, divided to two distinct populations. On one side, those aged 75 and over, with a sample of 7.2 million people (50% vaccinated and 50% non-vaccinated). On the other, 50- to 74-year-olds, with a sample of 15.4 million people (50% vaccinated and 50% non-vaccinated).
In France, the vaccination campaign began on December 27, 2020 for the 75+ age group and on February 19 for those aged 65 to 74, and May 10 for 50- to 64-year-olds). The study followed these two populations until July 20 (with similar efficacy results in both age groups).
To compare the data, researchers formed pairs. For each person vaccinated on a given date, they matched an unvaccinated person of the same age, same sex and living in the same region.
They followed these “couples” until July 20 and compared hospitalization rates. This study focuses only on the efficacy of vaccines against severe forms. It does not allow to say to what extent they prevent being infected and transmitting Covid.