Test negative before ending self-isolation? Experts weigh in

As COVID-19 continues to evolve, so does the advice of medical experts. A sharp rise in the number of people getting infected multiple times means that topics such as isolation and contagiousness periods, and the proper use of home tests, are becoming more of a part of Long Islanders' daily lives.

Statewide, the reinfection rate was 75 times higher in early January 2022 than in early January 2021, according to state Department of Health data. The nearly 266,000 documented reinfections statewide likely is a significant undercount because it doesn't include home test results that are not reported to authorities. 

Newsday asked several experts about isolation, testing and other coronavirus-related matters. Much about COVID-19 remains unknown, so experts aren’t always in agreement. And recommendations may shift again, as the virus and knowledge of it changes.

What is the government guidance on self-isolation?

In December, the Centers for Disease Control and Prevention reduced the number of days — from 10 to five — it advised that people self-isolate after a COVID-19 infection, as long as you are fever-free for at least 24 hours without the help of medication and your symptoms are improving. Day 1 is the first full day after your symptoms developed or after you were tested.

Isolation means staying home and away from others in your home.

People who get very sick from COVID-19 or have weakened immune systems should consult a doctor before ending isolation.

Even after isolation, wear a well-fitting mask — experts advise an N95 or KN95 — up to Day 10, the CDC said. Many KN95 masks are fake, so make sure to get an authentic one, said Dr. Aaron Glatt, chairman of medicine and chief of infectious diseases at Mount Sinai South Nassau hospital in Oceanside.

Do I need to test negative before ending self-isolation?

The CDC says no, but adds that if anyone tests positive on an antigen, or rapid, test near the end of the five-day isolation period, “You should continue to isolate until Day 10" or until you test negative.

The CDC’s revised guidelines, and especially the lack of a testing recommendation, have divided experts for months. 

Dr. Dwayne Breining, executive director of Northwell Health Labs, supports the CDC guidelines, and he doesn’t believe people should have to “test out” of isolation.

“The risk isn’t high enough that you need to stay home longer than five days, because [if you no longer have symptoms] the chances are very high that you’re not contagious anymore, not zero, but it’s very likely you’re not contagious anymore,” he said.

Glatt agreed, although, like Breining, he believes that “extra caution is appropriate” after five days around people who are at high risk for severe COVID-19.

Wearing well-fitting masks from Day 6 to Day 10 is important, just in case you’re still infectious, he said.

But Denis Nash, a professor of epidemiology at the CUNY School of Public Health in Manhattan, and a former epidemic intelligence service officer with the CDC, said, “I find it very perplexing” that there’s no test-out requirement, especially because of the CDC’s “contradictory” advice that anyone who tests positive should continue in isolation past five days.

Stephanie Silvera, an epidemiologist and professor of public health at Montclair State University in New Jersey, also advises people to test negative before ending isolation.

If I test positive on Day 6 or beyond, does that mean I’m still contagious?

Breining said if you no longer have symptoms and test positive on a rapid test after five days, the chances are low that you’re still contagious.

But Silvera said people should assume a positive rapid test result means they’re contagious, no matter when the test is taken.

“For those rapid antigen tests, it means you are shedding active viral particles, which means you are still infectious,” she said.

Experts agree that you can test positive on the more sensitive PCR tests weeks after you are no longer infectious. So if you choose to test out of isolation, use a rapid test, Silvera said.

Why should I care about COVID-19 anymore? Isn't it a milder disease now?

“COVID is milder for people who have been vaccinated and for people who have otherwise healthy immune systems,” Silvera said. “If I have COVID, I would want to know if I’m actively contagious so that I don’t spread it to somebody for whom the consequences would be more dire.”

Death rates are down, but more than 2,000 Americans are still dying of COVID-19 every week, according to the CDC. Tens of thousands more are hospitalized every week.

Millions of Americans have long COVID, which is an array of symptoms — fatigue is the most common — that can persist for months or years, even sometimes in people with initially mild cases.

In addition, Silvera said, it’s unclear what long-term effects repeated COVID-19 infections will have on the body.

How do Long Island businesses handle isolation periods?

“What we’re seeing generally is compliance with the CDC guidelines,” with no negative test needed to return to work, said Domenique Camacho Moran, a labor and employment attorney and a partner at Farrell Fritz in Uniondale.

Do I get paid if I’m out with COVID-19?

New York State requires most businesses to provide 5 to 14 days of paid COVID-19 sick leave, with the amount depending on factors such as the size of the business.

That requirement is triggered only after the employee shows the business a government isolation order or submits a legally binding form. In reality, most businesses don’t require that, Camacho Moran said. Some will require a lab-verified positive test result; others will accept a home test result, she said.

What about schools?

Most school districts appear to be following state guidelines, said Donna Kraus, a spokeswoman for Phyllis Harrington, president of the New York State Council of School Superintendents and the superintendent for Oceanside schools. Those guidelines are based on CDC recommendations.

How long can I test positive?

Multiple studies have found that many people test positive on rapid tests well beyond five days.

A study published in February by the CDC’s Morbidity and Mortality Weekly Report found that more than 54% of those studied tested positive on a rapid test five to nine days after their symptoms began or after they first tested positive, and more than 38% tested positive on Day 9.

A line on a home rapid test indicates if someone is positive. Does it matter if that line is bold or faint?

Breining said “the darkness of that line is directly proportional to how much of the virus protein was on the swab.”

“That line will start out faint and then it will get darker and darker over the course of days, and then it will start fading out again,” he said.

Early on, you may be very contagious even if the line is faint, but near the end of your infection, a lot of the virus may not be transmissible, he said.

But Silvera said that even a faint line near the end of the infection indicates you may be contagious.

When am I most contagious?

“Two days or so before you had symptoms if you are symptomatic, to about three or four days after symptoms begin, is when you’re going to be most contagious,” Breining said.

How important is it to follow the instructions on the at-home tests, including swabbing the nostril for the required amount of time?

“It’s very important, because you want to make sure you’re getting an adequate sample,” Silvera said. If you don’t, you may test negative even if you’re positive, she said.

Likewise, make sure to squeeze the little plastic tube to extract virus from the swab, she said.

Breining said if you get a test outside the home and it appears that the person testing you “went superficially or very fast” with the swabbing, and you get a negative result, you should get another test. You should also test again if you have COVID-19 symptoms or if you were in an especially high-risk situation, he said.