The Centers for Disease Control and Prevention quietly changed its guidance on Monday to now say that asymptomatic people do not need to be tested for coronavirus, even if they have been in close contact with an infected person. The agency made the move by updating its website but did not make any public announcement or explain the reasoning behind the major revision. The guidance now states: “If you have been in close contact (within 6 feet) of a person with a COVID-19 infection for at least 15 minutes but do not have symptoms: You do not necessarily need a...