Five days. That’s how long you should isolate after testing positive for COVID before going back to normal life (while wearing a mask in public for five more days), according to the U.S. Centers for Disease Control. The CDC’s five-day quarantine policy for COVID cases is not law, but families, human resource departments, schools, and other institutions across the country depend on its advice for deciding how to return to normal life after a COVID infection.
Scientists have questioned the scientific rationale behind the five-day quarantine policy since the CDC introduced it last December. And now, critics of the policy have more data to back up their claims.
In two new preprints, scientists found that people infected with COVID-19 remained infectious after five days. One from the Massachusetts General Hospital in Boston showed that one-quarter of COVID patients may still be infectious eight days after first testing positive.
How long should you isolate after testing positive for COVID?
Extending the isolation period from five to ten days could be more safe, according to the study.
“There is not data to support five days or anything shorter than ten days [of isolation],” Amy Barczak, a physician at the Massachusetts General Hospital Infectious Disease Division, who contributed research to the study, tells Nature.
Some scientists advise that people should stop quarantining only once they test negative using at-home, rapid antigen tests (RATs) rather than relying on the CDC's five-day rule.
"There’s still all of these things that we’re not exactly sure about, but if I had to sum it up in one very concise message, it would be if you’re antigen positive, you shouldn't go out and interact closely with people who you don’t want to be infected,” says Emily Bruce, a microbiologist and molecular geneticist at the University of Vermont in Burlington, tells Nature.
Joe Biden is waiting to test negative for COVID
The mounting evidence poking holes in the CDC's five-day quarantine policy arrives as more Americans are relying on the guidance to decide when it's safe to return to work, school, or other every day activities.
In the U.S., like much of the world, COVID is currently spreading like wildfire, fueled by the rise of the Omicron BA.5 sub-variant. Officially, the U.S. is reporting 128,000 cases per day in the past week. But with testing nearing all-time lows, the real number could be multiples higher. Wastewater tests, which monitor sewage for traces of COVID, reveal record-high levels of the virus in the U.S.
U.S. President Joe Biden is among the Americans who have caught COVID amid the current BA.5 surge.
For Biden, who is currently working from home and isolating from others while recovering, the CDC's five-day rule is not sufficient. The White House says that Biden would go "above and beyond" the CDC's five-day guidance and wait until he tests negative before returning to seeing people in public. Biden first tested positive last Thursday and expects to resume in-person meetings by the end of this week.
This story was originally featured on Fortune.com