The real population data are the most relevant to measure the effectiveness of vaccines.
But, by definition, it takes time to dispose of it.
After several weeks of waiting and repeated requests, the Directorate of Research, Studies, Evaluation and Statistics (DREES) published this Friday in open data, for the first time, data "crossed" between databases of tests, hospitalizations, and vaccination related to Covid-19.
At the end of July, when the fourth wave of the epidemic had already started to affect the hospital, the unvaccinated represented a much larger share of this flow of daily hospitalizations than the vaccinated. On July 25, for 10 million people in each group, there were respectively 43.8 hospitalizations of unvaccinated people, 8.6 hospitalizations of people who received a single dose (or less than 7 days after receiving the second), and 6.9 hospitalizations of fully immunized each day. For critical care admissions, these numbers are 13, 2.7, and 1.1, respectively. And, for deaths, 2.8, 0.4 and 0.5. For a comparable population size, at the end of July there were 6.4 times more daily hospitalizations, 12 times more daily critical care admissions and 5,Twice as many daily deaths among the unvaccinated than among the fully vaccinated.
From July 7 to 25, the number of patients admitted daily to the hospital increased from 110 to 260 and that of patients entering critical care each day from 23 to 54, according to Public Health France.
"This increase was mainly carried by unvaccinated people," notes the Drees.
Over this period, daily admissions to conventional hospitalization increased threefold in the unvaccinated, and doubled in the unvaccinated.
The gap is much larger for critical care admissions: + 260% and + 41% respectively.
Territorial data soon
The data used for these calculations relate to patients whose SARS-CoV-2 infection was established by a positive PCR test in the previous 21 days, which is the majority of them.
The trends are similar if we also include patients treated for suspected Covid.
There is nevertheless a discrepancy with the daily data from Public Health France.
This could be explained in particular by the fact that the DREES did not take into account patients whose age was not informed, or if the vaccination status was not known for some of them.
Still concerning the methodology, the vaccine coverage used is, for each day of entry to the hospital, those estimated on D-7 in order to take into account the time between contamination and hospitalization.
Read alsoCovid-19: can we really say, like Jean Castex, that "96% of 18,000 cases" Tuesday were unvaccinated?
The small difference between the numbers for the unvaccinated and those for the partially vaccinated may come as a surprise, as studies with the Delta variant suggest limited efficacy with a single dose.
This can undoubtedly be explained by the fact that these data relate to all ages combined. severe form of the disease if infected than the elderly.
This could explain why there are not more hospitalizations in the "one dose" group.
The Drees now plans to update this data every week, but without specifying whether it will be broken down by age. On the other hand, they should be territory by territory. This will then make it possible to analyze whether there are different markers depending on the vaccination coverage.