CDC doubles down on isolation guidance, rejects more testing

The Centers for Disease Control and Prevention (CDC) on Tuesday did not formally recommend a negative COVID-19 test for a person to leave isolation after being infected and instead merely clarified that for anyone who has access to a test and wants to take it, a rapid antigen test at the end of the isolation period is best.

The agency essentially doubled down on its earlier guidance, released last week, that said people infected with COVID-19 can leave isolation and go back to work after five days if they are asymptomatic or if their symptoms are improving and they wear a mask for five days.

The CDC also recommended that anyone who is not fully vaccinated and boosted should quarantine for 10 days if exposed to someone who was infected. 

After the guidelines were released, the CDC faced a wave of criticism from health experts who said they were concerned that without a testing aspect, people would leave isolation while still contagious.

Top administration health officials, including White House chief medical adviser Anthony Fauci, have hinted in recent days that the guidance could be updated to include a testing component. 

But on Tuesday, the CDC said a test was merely an option if someone wanted to take one, as the value of a test toward the end of the five-day period is uncertain.

“Accumulating evidence demonstrates the majority of transmission occurs during the early periods of infection,” the CDC said, adding that coronavirus tests are not authorized by the Food and Drug Administration to evaluate the duration of infectiousness. 

“A negative antigen test does not necessarily indicate the absence of transmissible virus,” the CDC said, which is why people should continue to wear masks even after leaving isolation.

“If your test result is positive, you should continue to isolate until day 10. If your test result is negative, you can end isolation, but continue to wear a well-fitting mask around others at home and in public until day 10,” the agency said. 

Some experts have speculated that the CDC didn’t include a testing requirement because of the current shortage of rapid tests. In many places, at-home tests are difficult or impossible to find, and even if they are available, the prices are high. 

The CDC did not officially address the availability of tests. But in explaining why officials decided to shorten the isolation period, the agency said it took into account the “societal impact” from a large number of cases. 

“Spread of the Omicron variant has the potential to worsen staffing shortages and increase supply chain challenges, which jeopardize industry, education and other systems that are essential to maintain a functioning society and economy,” the CDC said.

Additionally, the agency cited challenges in people staying self-isolated and quarantined for the full period. 

“Studies suggest that only a small percentage of people (25-30%) isolate for a full 10 days,” the CDC said.