CDC says asymptomatic people don’t need testing, draws criticism from experts

The Centers for Disease Control and Prevention (CDC) 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 test unless you are a vulnerable individual or your health care provider or State or local public health officials recommend you take one.”

That is a stark change from the previous CDC guidance, which emphasized the importance of testing people who were in close contact with infected people.

“Testing is recommended for all close contacts of persons with SARS-CoV-2 infection,” the previous guidance said. “Because of the potential for asymptomatic and pre-symptomatic transmission, it is important that contacts of individuals with SARS-CoV-2 infection be quickly identified and tested.”

The move drew widespread criticism and confusion from public health experts, who said that testing to identify asymptomatic people with the virus is important and that the change could undermine contact tracing, a core strategy for slowing the spread of the virus.

“Without explanation, the @CDCGov made remarkable and troubling changes to their guidelines on coronavirus testing this week,” tweeted Carl Bergstrom, a professor of biology at the University of Washington.

“The most recent guidelines seem to give up any pretense of using contact tracing to control COVID,” he added. “The whole point of contact tracing is to find asymptomatic contacts of known cases and isolate them. If you aren’t even going to test them? Certainly no point in tracing.”

Angela Rasmussen, a virologist at Columbia University, was more succinct in her tweet.

“Now what the hell kind of CDC recommendation is this? We need to be doing MORE testing, not less,” she wrote.

Now what the hell kind of CDC recommendation is this? We need to be doing MORE testing, not less. https://t.co/hv1bPM5wdj

— Dr. Angela Rasmussen (@angie_rasmussen) August 24, 2020

While the CDC issued the new guidance, a spokesperson for the agency declined to comment and referred questions to the Department of Health and Human Service’s (HHS) assistant secretary for health, Brett Giroir.

“This Guidance has been updated to reflect current evidence and best public health practices, and to further emphasize using CDC-approved prevention strategies to protect yourself, your family, and the most vulnerable of all ages,” Giroir said in a statement. 

He added that the guidance puts emphasis on testing vulnerable people.

“The updated Guidance places an emphasis on testing individuals with symptomatic illness, those with a significant exposure or for vulnerable populations, including residents and staff in nursing homes or long term care facilities, critical infrastructure workers, healthcare workers and first responders, and those individuals (who may be asymptomatic) when prioritized by public health officials,” he said.

Two key Republican senators, Lamar Alexander (Tenn.) and Roy Blunt (Mo.), have been among those pushing for much more nationwide testing, including of people who are asymptomatic and have touted a National Institutes of Health initiative to develop new testing technologies to enable millions more rapid tests.

In a USA Today op-ed this month, they set a goal of widespread testing to “be sure you and your child are healthy before she goes to school or you head out to work or to dinner or to visit parents or grandparents you haven’t seen in months.”

Identifying asymptomatic people who are infected is also important for contact tracing, the process of tracking down people who have been in contact with an infected person so they can isolate.

“If I have been exposed but asymptomatic, I am at heightened risk for being infected and infectious,” Bergstrom wrote in an email. “We definitely want to test me in that situation, and if I am positive trace my contacts.”

He added that contacts of infected people are less likely to comply with requests to isolate for 14 days if they are not tested. “If we want compliance, we need testing,” he wrote.

“Many of us are confused by @CDCgov excluding people without symptoms from testing guidelines,” tweeted Natalie Dean, a professor of biostatistics at the University of Florida, pointing to HHS saying the revision was based on “current evidence.”

“But what is the evidence?” she asked.