A patient diagnosed with pneumonia near Paris on December 27 actually had coronavirus, said his doctor.
Dr. Yves Cohen told French media that a sample taken at the time had been recently tested and that it returned positive for Covid-19.
The patient, a man in his 50s who has since fully recovered, said that he had no idea where he got the virus as he had not visited any area infected.
The news means that the virus may have arrived in France almost a month earlier than expected.
So far, the country’s first three cases of coronavirus have been confirmed on January 24.
Of these, two had traveled to Wuhan, China – where the epidemic was first detected – and the third was a close family member.
How was the new case found?
Dr. Cohen, chief of emergency medicine at Avicenne and Jean-Verdier hospitals near Paris, told French broadcaster BFMTV that he had recently reviewed the records of patients admitted for flu-like symptoms in December and January.
In total, he tested the swabs of 14 patients, he said.
“We re-tested the nasal swabs that were done at the time in connection with another diagnosis, to try to find traces of the coronavirus,” he said.
“One out of 14 patients tested positive. We tested it twice more to make sure there were no errors. And twice he came back positive. “
Dr. Cohen said he alerted the National Health Agency (ARS) and urged other virologists to retest swabs in their hospitals for Covid-19.
A full report is due later this week and will be published by the International Journal of Antimicrobial Agents, he added.