Vaccination against Covid-19 reduces the risk of hospitalization and death by 90% in those over 50. This is shown by a large study conducted by the Epi-Phare structure (bringing together Health Insurance and the Medicines Agency (ANSM) and published this Monday, October 11.
To achieve this result, the 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, over a period of December 27, 2020 ( start of vaccination in France) on July 20. From the 14th day after the injection of the second dose, the researchers observed “a reduction in the risk of hospitalization greater than 90%”.
This work focused on the Pfizer / BioNtech, Moderna and AstraZeneca vaccines. On the other hand, that of Janssen, which was authorized in France later, was not included in the study.
These data confirm empirical observations made in Israel, the United Kingdom or the United States. According to epidemiologist Mahmoud Zureik, director of Epi-Phare, this is “the largest study carried out in the world”.
Efficacy to be confirmed against the Delta variant
The vaccines would also be effective against the Delta variant, on which we still lack perspective. To identify the impact of this variant, which is now dominant, the researchers specifically estimated the reduction in the risk of hospitalization during the period when it gained momentum in France, from June 20 ( therefore one month before the end of the study). They found results comparable to previous periods: an effectiveness of 84% in those 75 and over, and 92% in those 50-74.
This makes it possible to provide “initial elements”, but “this period remains very short to assess the real impact of vaccination on this variant”. “The study must be continued to integrate data for August and September,” said Professor Zureik.
“This reduction is of the same order of magnitude for the risk of death during hospitalization for Covid-19”, according to Epi-Phare. In addition, the efficacy on severe forms of the disease “does not seem to decrease over the available follow-up period, which was up to five months”.