Still Testing Positive For COVID-19 After 10 Days? Here's What To Know

Once again, it's the time of year when respiratory illnesses — including COVID-19 — make their comeback. So, as we gear up for another winter virus season, take a moment to make sure you know how and when to properly use at-home COVID tests.

We don't know exactly what this year's winter COVID situation will look like, but it's a good bet that there will be a rise in coronavirus cases as we've seen during and after previous holiday seasons, Dr. Geeta Sood, an assistant professor of medicine and hospital epidemiologist at Johns Hopkins Bayview Medical Center, tells TODAY.com.

The "wild card" in predicting possible COVID waves is the emergence of new coronavirus variants, Sood says, and how transmissible they are.

But even as variants shift, we can still rely on rapid antigen tests to prevent the spread of COVID-19 and protect our communities. But, as always, your COVID test results — whether positive or negative — are only helpful if you know how to interpret them.

While most people will clear the virus and get a negative antigen test result within 10 days, some people may keep testing positive for longer than that, experts tell TODAY.com. And if you keep testing positive for 10 days or more, the safest approach may not be obvious.

The best way to protect yourself and those around you remains the same: Take advantage of precautions like updated COVID-19 vaccines, masks and testing. Here's what to know about when to take a COVID-19 rapid test, how to correctly interpret the results and when it’s safe to stop isolating — even if you’re still testing positive at 10 days and beyond.

How Long Can You Test Positive for COVID-19?

The experts TODAY.com spoke to all agree that most people will stop testing positive for COVID-19 on a rapid antigen test within 10 days. But, they say, there's a lot of variability from person to person when it comes to how long someone might continue to test positive.

"The antigen testing will tell you if you have actual current viral replication," Sood explains, so positive result tends to be "pretty transient" for most people.

That said, "there's a huge individual variability in the testing results and viral shedding and viral persistence," Sood explains. "So, yes, there are some people who will have antigen testing positive for a week to two weeks."

And Dr. Richard Martinello, professor of internal medicine and pediatric infectious diseases at the Yale School of Medicine, tells TODAY.com that he's "definitely" seen people test positive for longer than five to 10 days.

For instance, it's possible to develop a COVID rebound in which they test positive after testing negative, or develop symptoms again after their symptoms resolved. This can occur with or without taking the antiviral medication Paxlovid, Martinello says. And if someone does rebound after taking antivirals, "they were probably going to be sicker for a longer period of time, and so they did get some benefit from it," he explains.

It’s also possible to get COVID-19 more than once — even four or five times. So if there’s a gap of weeks or months in between your positive tests, you might actually have a whole new infection.

And, when it comes to PCR tests, which look for the virus’s genetic material, people may test positive for much longer than they're contagious, Dr. Daniel D. Rhoads, chair of the College of American Pathologists microbiology committee, tells TODAY.com.

When to Take an At-Home Rapid Test for COVID-19:

If you develop any symptoms that might signal COVID-19, taking a test can help determine what to do next.

Despite changes in which coronavirus variants are circulating now, the most common symptoms remain largely the same.

Be on the lookout for cold- and flu-like symptoms, including:

• Sore throat
• Fatigue
• Fever or chills
• Sneezing
• Congestion
• Runny nose
• Cough
• Headache
• Muscle aches
• Altered sense of taste or smell

Some of those symptoms — congestion, sore throat, cough, fever — might be easily confused with other common illnesses, such as the flu, allergies, RSV or the common cold. But it's a good idea to take a test to help rule out COVID-19 first, even if you may just be dealing with seasonal allergies.

Fall allergies are also spiking at this time of year, Dr. Zachary Rubin, an allergist with Oak Brook Allergists and spokesperson for the American College of Allergy, Asthma and Immunology, told TODAY.com previously.

Indoor allergens — dust mites, mold, pet dander — also tend to cause more symptoms around this time of year when we spend extra time inside, he said.

And it's not unusual for patients to assume they have allergies only to test positive for COVID-19, he said. So, be on the lookout for a fever (which is not a symptom of allergies) an don't hesitate to take a test to get a little more clarity.

If You Test Positive for COVID-19...

If you test positive for COVID-19 on a rapid antigen test, you should trust that result. Stay home and away from others as much as possible, even using a separate bedroom and bathroom if possible, experts say.

And remember that even a faint line on a home COVID-19 test should be considered positive. If you’re not sure whether your test is truly positive, you should check with your doctor, get a PCR test or take a second rapid test the next day (and behave as if you really do have COVID-19 in the meantime).

In the event that your test is negative even though you have noticeable COVID-like symptoms or you know you were exposed to someone with COVID, the Food and Drug Administration recommends taking a second test two days later. Depending on your symptoms and exposure, you may want to take a third rapid test another 48 hours after that, the FDA says.

After You Test Positive, Should You Keep Taking At-Home COVID-19 Tests?

If you get a positive test on a home rapid antigen test, you can trust the result, experts tell TODAY.com, provided you performed the test correctly. That means you generally don't need to keep testing yourself throughout your illness.

Testing every day to determine when you're no longer contagious has "fallen out of favor a little bit," Martinello explains.

That's partly because we have less access to free at-home tests these days, he says, but also because we have other ways to gauge how contagious we are. Just follow your symptoms, count the days — and continue to mask up around others.

But those with more moderate or severe cases and those who are immunocompromised may need to perform more tests to leave isolation based on advice from their medical team.

Does a Positive COVID-19 Test After 10 Days Mean You're Still Contagious?

As long as you continue to test positive on a rapid at-home test, you should still consider yourself potentially contagious.

"Of course, we always worry about it being indicative that they're still contagious, and that may be true," Martinello says. "But we also know that there's probably some circumstances where they're not contagious, but they're still testing positive," he adds.

So, how should you interpret a positive test late into a COVID infection? "Just like anything in medicine and in public health," Sood says, consider the risks and benefits.  

"If you were going to be cautious, which I hope most people are," she says, the absolute safest thing to do would be to "continue isolation because (the positive test) is a sign that there's viral replication happening." 

That said, not everyone is able to take that much time away from work, school or other obligations. And you are likely to be less contagious after 10 days than you were at the beginning of your infection, Rhoads says. If you're still testing positive after 10 days, "I'm not convinced that we are confident we know what that means in terms of infectiousness," he adds.

So, as experts told TODAY.com recently, it's much easier and generally sufficient to rely on monitoring your symptoms rather than waiting for that elusive negative test to leave isolation.

If you're feeling sick, especially if you have a fever, you should continue to stay home, Martinello says. But once your symptoms are getting better and you've been without a fever (without the help of fever-reducing medication) for at least 24 hours, you can start to go back to your normal activities — whether or not you test positive on a rapid test.

While the risk of spreading the illness isn't zero, by taking the necessary precautions (wearing a mask, distancing yourself if possible from others) you will be significantly cutting down that risk.

"Few things are black and white, but what we do know is that it's safer to mask," Martinello says. And you should continue to use those precautions when around others for another five days after your isolation period ends, experts advise.

Of course, if you're concerned about how long you've been testing positive, check in with a health care provider for guidance on your individual situation.