As deconfinement approaches, and in order to get out of this unprecedented health situation, it is essential to understand the level of circulation of the coronavirus in the population, how many people have been affected by the virus, to determine collective immunity, the percentage of people immunized against the virus. Researchers from the Institut Pasteur, in collaboration with Santé Publique France and Inserm, carried out a detailed analysis of hospitalizations and deaths due to COVID-19 in France. Europe 1 reveals to you this morning their first results, more disappointing than expected. They show that 5.7% of the French population has probably been contaminated.
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5.7 French people infected
The president of the scientific committee Jean-François Delfraissy himself estimated a few days ago that 10 to 12% of the population had encountered the virus. The results indicate that it is two times less: only 5.7% of French people. The level of immunity is therefore much lower than the level necessary to avoid a second wave if all control measures were to be lifted (70%).
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To obtain this result, the researchers of the Institut Pasteur analyzed all the figures on hospitalizations due to the coronavirus in the country by cross-checking them with numerous epidemiological surveys on the disease. One of the hypotheses to explain this weak collective immunity, is the underestimation of the so-called asymptomatic cases, those people who are ill without knowing it.
R0 down, 13% mortality in men over 80
Another very important result, the R0, the number of basic reproduction, that is to say the number of people that a patient contaminates. According to this study, this R0 is currently 0.5, whereas it was 3.3 before confinement.
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Which means that the containment works well, maybe even better than expected. With these models, the researchers consider that there should be between 10 and 45 new cases per day of coronavirus on May 11. Far from the 1,000 cases identified before confinement.
Other results of the study: the risk of hospitalization for people infected with the virus is 2.6%. But it increases with age to reach 31% in men over 80 years of age. The mortality rate in infected people is around 0.5% (13% in men over 80). The probability of death is 45% higher in infected men than in infected women, with a differential that increases with age.