At the risk of being a pedant, it's not the flu. Flu is caused by the influenza virus, covid-19 is a subtype of the coronavirus, which causes SARS, MERS and a few other conditions only seen in animals.  It's different from flu in several ways, notably in that it's believed to spread through the membranes of the eyeballs, causes miscarriages and is far more contagious than flu, with someone contagious with flu giving it to about 1.2 people  and people with covid-19 giving it to around 3 others.