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Covid-19 'probably' circulating in France from November 2019
11 February 2021, 11:39 | Updated: 11 February 2021, 11:54
Covid-19 was probably circulating in France as far back as November 2019, French researchers have found in a study that challenges the theory that the pandemic originated in a market in Wuhan, China.
Work by French scientists, published on Saturday in the European Journal of Epidemiology, suggests that the original strain of coronavirus was being spread in the country prior to the identification of the December outbreak in China.
"This report suggests that SARS-CoV-2 infection may have occurred as early as November 2019 in France," the paper reads.
"In several participants... we identified symptoms, history of possible exposures, or specific events compatible with early SARS-CoV-2 infection."
The study - led by Professor Fabrice Carrat, director of the Pierre-Louis Institute for Epidemiology and Public Health for Inserm at Sorbonne University - involved collecting serum samples from 9144 adults in the French population, of which 353 had tested positive for Covid-19.
Among those, 13 were confirmed through antibody testing to have had the virus between November 2019 and January 2020, with all but two of these experiencing Covid symptoms prior to testing positive.
"This suggests early circulation of SARS-CoV-2 in Europe," the paper says.
Its conclusions state that "it is unlikely that all were false positive results" and that through a detailed investigation they had found several participants had a "compatible history of exposure" to coronavirus.
The study's results support an investigation in Italy that also suggested earlier circulation of coronavirus in Europe, the researchers said.
However, the group acknowledged that the findings could have resulted from a lack of specificity in the study's serological methods and that there could have been misclassifications in some patients.
"We started by analysing samples taken in January and February, and we found many more positive ones than we expected," epidemiologist Marie Zins for Inserm at the University of Paris wrote for French newspaper Le Monde.
"So we looked to see if we could find any as early as the fall."
Research-lead Prof Carrat said: "These results suggest that, from November and December, the rate of contamination in the French population is already of the order of one case per thousand."
It comes following a study conducted in May 2020, in which doctors at the Albert-Schweitzer hospital in the eastern-French city of Colmar reanalysed hundreds of chest scans of patients admitted to the infirmary from October 2019 onwards.
Of these, one patient, who was hospitalised on 16 November, had lesions that suggested they may have had Covid-19.
However, researchers were still sceptical that an outbreak was ongoing in France at this time as insufficient analysis of biological samples had occurred - until the February 2021 study was published.
Separate research, by the National Cancer Institute (INT), of the Italian city of Milan also suggested coronavirus was circulating in Italy in September 2019.
Italy’s first Covid patient was detected on 21 February 2020 in a small town near the city, in the northern region of Lombardy.
The UK and French governments have both been approached for comment.