And if the Covid-19 had circulated before the first case officially listed on January 24?
In France, 200,000 people drawn by lot participate in a vast epidemiological study. The volunteers, united in a cohort called Constances, have been monitored regularly since 2012, via questionnaires and health examinations. Biological samples, such as blood samples, are kept in a biobank for further study. The objective is to monitor the health of participants over the long term and in fine better understand the factors that influence it such as diet, environment, working conditions, etc.
With the arrival of the coronavirus, Inserm researchers came up with the idea of using the blood samples taken to study, retrospectively, the HIV status of participants. In other words, to look for the presence of anti-SARS-CoV-2 antibodies in their blood serum.
In total, more than 9,000 samples were collected. Results ? The serological test identified the presence of antibodies to SARS-CoV-2 in 353 participants, including 13 who had their blood drawn between November 2019 and January 2020. Of these, 11 were investigated further: 6 reported no symptoms in the weeks before sample collection but 5 showed signs of viral respiratory illness. In addition, 8 had been in close contact with people who presented such signs or reported situations at risk of potential exposure to SARS-CoV-2.
These data published in European Journal of Epidemiology therefore suggest early circulation of the virus in Europe, says Inserm.
A first positive patient in France in December
Officially, the first cases were recorded on January 24: a Frenchman of Chinese origin and two Chinese tourists who stayed in Wuhan, the source of the epidemic.. Corn, the Prof. Yves Cohen, Head of the intensive care unit at the Jean Verdier hospital in Bondy (93), had already mentioned a circulation from the end of 2019.
The doctor, who retrospectively reviewed 24 records of patients with pneumonia, reanalyzed the PCR tests. And surprise: a patient hospitalized at the end of December for severe pneumonia was positive for Covid-19, suggesting that it was patient 0.
Source:
Inserm press release, February 10, 2021.
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