Eighty-six percent of people in China who were infected with novel coronavirus (SARS-CoV-2) were not tested in the two week period before travel restrictions came into force on January 23 in Wuhan and other cities. And these undetected cases contributed to the majority of virus spread in the community, says a paper published in the journal Science. The paper says that undetected cases can expose a large population to the virus than would otherwise occur. The study found undetected cases were the source of infection for 79% of documented cases.
And this is precisely why you must stay at home as much as possible in the near term future. Limit your movements, avoid crowds, use common sense.