https://www.mercurynews.com/2020/02/01/can-i-get-coronavirus-from-someone-whos-not-sick/

If I’ve traveled to China but I feel fine, why does the U.S. want to quarantine me?

That’s a question being asked in the wake of Friday’s extraordinary order of a mandatory quarantine of all Americans returning to the U.S. from China’s most affected area — and a voluntary “self-quarantine” of anyone who’s been anywhere in China over the past 14 days.