Of the 44,672 coronavirus cases that were confirmed in China by Feb. 11, more than 36,000 — or 81 percent — were mild, according to a study published recently by the Chinese Center for Disease Control and Prevention.

Cases were considered mild if they did not involve pneumonia, defined as infection of the lungs, or involved only mild pneumonia, the authors wrote in the study, which is among the largest to date of the new coronavirus…

The overall fatality rate in China was 2.3 percent. But that number was inflated by the much higher fatality rate in Hubei Province, of 2.9 percent, compared with a rate of just 0.4 percent in the rest of the country. The seasonal flu, by comparison, has a mortality rate of about 0.1 percent…

Those with mild or no symptoms may not know they have contracted the virus, or may pass it off as a seasonal cold. They may then continue in their daily lives — traveling, kissing, coming into close contact with others — and spread the virus without anyone knowing.