Health Experts Alarmed by CDC Cutting COVID Isolation Time: 'Reckless'

Several experts on immunology and epidemiology have criticized the decision by the Centers for Disease Control and Prevention (CDC) to reduce the self-isolation period for those who test positive for COVID-19.

The CDC announced on Monday that those who test positive and are asymptomatic should now isolate for five days instead of 10, citing evidence that people are most infectious two days before they develop symptoms and three days afterward.

However, some health experts expressed confusion and apparent anger at the CDC's updated advice with one professor of immunology taking to Twitter to say the decision left him "baffled."

Epidemiologist and immunologist Michael Mina tweeted: "CDC's new guidance to drop isolation of positives to 5 days without a negative test is reckless."

"Some ppl stay infectious 3 days, Some 12," he wrote.

"I absolutely don't want to sit next to someone who turned Pos 5 days ago and hasnt tested Neg," he went on. "Test Neg to leave isolation early is just smart."

Mina criticized the idea that those with COVID should end isolation before testing negative and also took aim at the CDC's claims about when patients are most infectious, arguing that information predated the Omicron variant.

Erin Bromage, associate professor of comparative immunology at the University of Massachusetts, Dartmouth, expressed similar concerns. He shared two images of positive COVID tests on Twitter by way of explanation.

"I am baffled at CDC's decision to shorten isolation," Bromage wrote. "Here are tests from the same person: day 0 (3 days after exposure) and day 8. The person still has a huge amount of virus in their nose 8 days after testing positive."

Bromage said he oversees the testing of thousands of people each week in workplace surveillance programs.

"As we do not want to have workplace transmission, we ensure that [w]hen we have a positive we do not return them to work too soon. Workplace transmission would shut us down (union rules) so we are cautious and use data to return people," he wrote.

Eric Feigl-Ding, an epidemiologist and health economist, highlighted the surge in the Omicron variant of the virus across the U.S. as he questioned the CDC's decision.

"50% CUT—does this makes sense—CDC shortens #COVID19 isolation period for those without symptoms (self-reported) to just 5 days, instead of 10," Feigl-Ding wrote. "All while #Omicron cases surpassing last year's peaks with hospitalizations up too—I really worry about this."

Feigl-Ding noted in a later tweet that CDC advice differs from the situation in the U.K. where two negative tests are required to exit isolation before 10 days.

"But somehow a 5 day exit with 0 negative test is okay in [the U.S.]? American exceptionalism does not apply to a pandemic virus," he wrote.

Patrick Hickey, chair and professor of pediatrics at Uniformed Services University, retweeted Feigl-Ding and added simply: "Co-sign."

The CDC advised on Monday that those who test positive but are asymptomatic should wear masks around other people for five days after leaving isolation.

The agency also recommends that unvaccinated people and those who received their second mRNA vaccine dose more than six months ago and aren't boosted should isolate for five days if they are exposed to the virus. They should then wear masks around others for a further five days.

CDC director Dr. Rochelle Walensky said on Monday that many cases of the Omicron variant "are going to be asymptomatic."

"We want to make sure there is a mechanism by which we can safely continue to keep society functioning while following the science," she said.

Newsweek has asked the CDC for comment.

Airport Travelers Arrive for COVID-19 Testing
Travelers with their luggage arrive at Covid-19 Testing location at the airport in Los Angeles, California on November 23, 2021. The CDC has issued new guidance on self-isolation for asymptomatic people. FREDERIC J. BROWN/AFP/Getty Images