Articulate health data and social conditions: since the start of the Covid-19 epidemic in France, no study had been launched to jointly assess the two aspects of the epidemic, and even less on the scale of the whole population. Co-led by sociologist Nathalie Bajos, director of research at Inserm, and Josiane Warszawski, epidemiologist at Inserm, the Epicov survey, conducted in collaboration with Drees and INSEE, is work that has only just started . Nathalie Bajos explains the process.
What is it about ?
The objective is twofold. On the one hand, measure very finely, at the departmental level, the proportion of people who have been in contact with the virus. On the other hand, understand the effect of confinement and traffic restrictions on living conditions. What type of accommodation were we confined to? Have we gone teleworking? The survey focuses on people in so-called “essential” work, who are at risk because they must continue to go out during confinement, use public transport or be in contact with the public. We often speak, and rightly so, of the nursing staff. In this survey, the perspective is broadened to include cleaning staff, delivery men, police, supermarket workers, teachers who have continued to educate children.
When was it launched?
The decision was made on March 15 but the time to prepare all the logistics, we actually started on May 2. A cohort of 200,000 people over the age of 15 was drawn by INSEE according to the statistical rule for representative samples. The survey will be repeated in several parts to monitor both the evolution of the virus and that of living conditions.
How do we know if people have been sick or tested? From what they report or by cross-checking with other data?
We rely on the statements. Symptoms related to Covid, cough, fever, respiratory disorders, loss of smell or taste, fatigue … But also other health problems, in particular chronic pathologies because one of our questions concerns access to care. In this period when the health services are completely overwhelmed, how did you manage the other health problems? Finally, at the end of the questionnaire, we suggest that all those involved in this research effort do a very simple test at home, consisting of pricking the tip of the finger to place a few drops of blood in five places on a blotter. All this is returned by post. It is not a virological test, it is a serological test: we will know if people have been at one time or another in contact with the virus, whether they have symptoms or not, and whether they are still carrying the virus or not.
Do all respondents accept the test?
At this stage, no figures can be given, but the returns show very good acceptance. Beyond their personal situation, one might think that people want to participate in a scientific investigation.
How many responses have you already had?
So far, several thousand. Responding takes twenty to thirty minutes for the questionnaire and five for the test. However, the challenge is above all that all social circles can respond. The sample is perfectly representative of the population and we particularly observe people who live in precarious economic conditions.
Is it possible to reach them with a survey that goes through the Internet?
We offer people who do not have digital access to fill out a questionnaire by phone.
What’s the calendar ?
A first wave is planned until the end of May and we will launch a second in a few weeks from the results of the first. The idea is to repeat it several times. We have planned four waves of investigation to really follow the development of the situation in France. It’s not about just documenting what’s going on right now. We are in a completely new situation, by the extremely high contagiousness of the virus and by the prevention measures which, as we can see, are experienced differently depending on whether or not you are working, whether you are confined to a large apartment garden or with others in a small apartment. Those who are not included in the survey are people living in nursing homes, prisoners or the homeless. But even if no work of this type is representative of the entire population, it is part of the large national surveys. Our goal is to reach all social circles and go down to the departmental level. When you see the heterogeneity of the situations on the territory, it is extremely important to be able to reach this level of finesse. An investigation like this can also help inform policy decisions.