COVID-19 has been retrospectively diagnosed in a man treated in an intensive care unit (ICU) near Paris after coughing up blood on Dec 27, 2019—4 days before the novel coronavirus cluster was identified in Wuhan, China.This finding, published this week in the International Journal of Antimicrobial Agents, suggests that the coronavirus was already circulating undetected in France well before the first cases were reported there on Jan 24 in two returned travelers from Wuhan.Signs, symptoms likely led to flu misdiagnosisSuspecting that COVID-19 cases may have been mistaken for the flu, which causes similar signs and symptoms, the researchers reviewed medical records of ICU patients hospitalized with flu symptoms from Dec 2, 2019, to Jan 16 who