Study: COVID-19 Patients Still Infectious Beyond 5-Day Isolation Period

ADF STAFF

Five days has become the recommended time for people infected with COVID-19 to isolate themselves before returning to their normal routines. But new research suggests that that period might be too short to keep people from spreading the virus.

“There is not data to support five days or anything shorter than 10 days,” Amy Barczak, a doctor and researcher at Massachusetts General Hospital in Boston, told the magazine Nature.

Barczak’s own research on patients in her hospital shows that at least a quarter of people carrying a strain of the omicron variant remain infectious for up to eight days.

Many variables affect the length of time that someone can continue to shed virus particles. People with established immunity tend to recover more quickly from infections. But as new variants evolve, health experts are reconsidering the safety protocols that guide treatment.

“We always think of it as a black-and-white thing,” virologist Benjamin Meyer of the University of Geneva told Nature. “But, in reality, it’s a numbers game and a probability.”

The five-day threshold was set by the U.S. Centers for Disease Control and Prevention in December 2021 with the recommendation to wear a mask in public for five additional days.

“The change is motivated by science demonstrating that the majority of SARS-CoV-2 (COVID-19) transmission occurs early in the course of illness, generally in the 1-2 days prior to onset of symptoms and the 2-3 days after,” the agency said at the time.

The new research on infectiousness has come to light as the highly transmissible BA.4 and BA.5 strains of the omicron variant sweep the globe — a reminder that the pandemic remains a threat.

According to the World Health Organization (WHO), deaths worldwide from COVID-19 rose 35% between mid-July and mid-August. In a single week in mid-August, 15,000 people across the globe died from the disease.

“Fifteen thousand deaths a week is completely unacceptable when we have tools to prevent infections and save lives,” WHO Director-General Dr. Tedros Adhanom Ghebreyesus said during his weekly briefing.

The BA.5 strain of the omicron variant is the dominant strain worldwide, representing more than 90% of sequences examined, Tedros said.

The number of sequences being reviewed has dropped 90% since the beginning of the year, a product of falling testing numbers as people become less concerned about the virus.

Tedros warned that transmission could increase sharply as winter returns to the Northern Hemisphere and people spend more time indoors.

“There’s a lot of talk about learning to live with this virus,” Tedros said. “Learning to live with COVID-19 does not mean we pretend like it is not there. It means we use the tools we have to protect ourselves and protect others.”

When checking for a lingering infection, researchers told Nature that widely available rapid antigen tests offer the best indicator of whether someone is still capable of spreading the virus. That’s because rapid tests detect proteins viruses produce as they replicate.

Emily Bruce, a molecular geneticist at the University of Vermont, told Nature that rapid tests can remove any doubt regarding the risk a person recovering from COVID-19 might pose to others.

“If I had to sum it up in one very concise message, it would be that if you’re antigen positive, you shouldn’t go out and interact closely with people who you don’t want to be infected,” she said.