Testing is the only way to know for sure if you have the flu or coronavirus. But there have been problems with coronavirus testing — from faulty test kits to major shortages and delays in getting tested.

The flu and coronavirus share some common symptoms, such as fever and cough, but shortness of breath is a common hallmark of coronavirus.

Of course, some people with coronavirus have no symptoms at all. And asymptomatic people can still spread coronavirus to others.

So anyone who has had close contact with someone known to have coronavirus should ask a health care provider about getting tested, the US Centers for Disease Control and Prevention said.

Anyone who recently traveled to a part of the world where coronavirus is widespread should do the same.