3.7 million people will have contracted the coronavirus Covid-19 in France by May 11. Men are also more likely to be infected than women.
Less than 6% of French people will have been infected with Covid-19 by deconfinement. This is confirmed by a new study by the Institut Pasteur, pre-published this Tuesday 21st April 2020 in collaboration with the National Institute of Health and Medical Research (Inserm) and Public Health France.
In total, 3.7 million people could contract the disease in France or 5.7% of the population. A rather small proportion, which is mainly due to confinement: “the average number of people infected with a case rose from 3.3” before March 16 to 0.5 during confinement, explains the study.
#COVID19 : selon une étude, près de 6% de la population française aura été contaminée par le SARS-CoV-2 au décours de la première vague épidémique. @institutpasteur @santeprevention @CNRS https://t.co/SUPrOTykl9
— Institut Pasteur (@institutpasteur) April 21, 2020
Men most at risk
To arrive at these results, the scientists crossed the data on deaths and the probability of dying once infected, in order to arrive at an estimate of the share of the population affected by the coronavirus.
Note that the figures vary with age and sex. Men are “much more at risk of dying when they are infected than women (they have a 50% greater risk than women)”, underlines Simon Cauchemez, epidemiologist and one of the authors of the study.
This difference increases with age, continues Simon Cauchemez with the AFP , with a death rate of 13% and a risk of hospitalization which can reach 31% in men aged over 80 years.
Variations by region
This projection of the number of people who could be infected by May 11 also varies from region to region. According to data from the study, which confirms a situation already widely observed in the field, the Grand-Est and Ile-de-France regions are the most at risk, with 11.8% of the population of Grand-Est and 12 , 3% of the population of Ile-de-France which could be contaminated by Covid-19 by May 11.
The regions which would fare best are New Aquitaine (1.4% of the regional population), Brittany (1.8%) and the Pays de la Loire (1.9%).
This variation is even more visible on this map representing the estimate of the proportion of the population infected by May 11 in each of the regions of metropolitan France.
Maintain measures after May 11th
For scientists, this level of contamination nevertheless remains very insufficient to avoid a second epidemic wave with a view to complete deconfinement and the lifting of all measures after May 11th, 2020.
Indeed, the proportion of infected should rather be around 70% to obtain collective protection by group immunity alone.
The only effective solution to avoid a second major wave of infection (and death), says the study: maintaining the measures after May 11th, 2020, and developing a vaccine.
On en parle plus qu'on ne le voit. Ci-dessous, une cellule respiratoire infectée par le SARS-CoV-2. En rouge & jaune, des vésicules caractéristiques du cycle de vie d'un #virus contiennent le matériel viral nécessaire à sa réplication & à l'infection d'1 nouvelle cellule #COVID19 pic.twitter.com/z9K363rgAG
— Inserm (@Inserm) April 20, 2020