After Criticism, C.D.C. Reverses Covid-19 Guidelines on Testing People Who Were Exposed

The Centers for Disease Control and Prevention on Friday reversed a recommendation that people who have had close contact with someone infected with the coronavirus did not need to get tested unless they had symptoms.

The change came after widespread criticism of the earlier guideline, as well as reporting from The New York Times that the recommendation had come from political appointees in the Trump administration and skipped the agency’s usual, rigorous scientific review.

The Times reported Thursday that the guideline was posted on the C.D.C. website despite strenuous objections from the agency’s scientists.

The previous phrasing, which said asymptomatic people who have had close contact with an infected individual “do not necessarily need a test,” now clearly instructs them: “You need a test.”

Public health experts welcomed the change as consistent with research showing that people without symptoms can spread the virus. Some research has suggested that they are actually most likely to transmit to others starting around a day before the onset of symptoms, when the viral load can be the highest.

“It’s good to see science and evidence