If you continue to test positive for covid, when will you be able to stop being isolated? : Shot

Science is not entirely sure whether a rapid antigen test will indicate whether a person is still contagious.

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Massimiliano Finji / Getty Images


Science is not entirely sure whether a rapid antigen test will indicate whether a person is still contagious.

Massimiliano Finji / Getty Images

Many Americans wrestled with this dilemma during the epidemic, yet it still seems to come up again and again: When can you stop being isolated after the Kovid-19 infection? The question is especially annoying if you feel good but are still testing positive on the fast test.

Even with the arrival of the new subvariant, the basic rules have not changed since Omicron first appeared: the Centers for Disease Control and Prevention says that if one is free of fever for 24 hours, the isolation can stop after five days and they start to get better – until then. They spend five more days wearing masks around others.

Some researchers have criticized these rules, pointing to studies that show that some people can stay infected even after five days. And many experts advise to wait until the negative test in the house-to-house test before going out.

But if you feel good, the wait can be frustrating, especially if you’re on a subset of those who have tested positive in the last 10 days.

James Hay, who studies the dynamics of infectious diseases, remembers earlier this year when his sister ran a positive test for two weeks. Their family plan was to get together on the holidays – a gathering to include an elderly relative who was at risk for Kovid.

“For us, it wasn’t worth the risk,” said Hay, a research fellow at the Harvard TH Chan School of Public Health. “Going to the store after the mask, consider it a different kind of risk.”

The test is tempting to come out of isolation because it promises a simple answer. Unfortunately – and perhaps surprisingly – science is not completely settled.

“We don’t have anything that says you’re contagious or definitely not,” said Dr. Emily Landon, an infectious disease specialist at Uchihago Medicine. “The best thing for us is this quick antigen test.”

In contrast to PCR testing, which searches for genetic material from a virus, rapid antigen tests work by looking for proteins packed inside the virus. A positive test is usually associated with the presence of an infectious virus. Scientists can determine if taking samples from an infected person and trying to spread the virus in a lab – which is known as a viral culture.

Generally, most people who become infected do not test positive for antigen even 10 days after the onset of symptoms.

If you have enough viruses in your system that make one of these tests positive, it means your body probably still hasn’t completely cleared the infection, ”O says.

But there is no perfect study that shows how much it is possible Dr. Geoffrey Baird, chair of the Department of Laboratory Medicine and Pathology at the University of Washington School of Medicine, said a positive test in rapid testing translates into a sufficient amount of virus secretion that you can actually infect another person.

“The answer is as clear as mud,” he says.

In fact, infectious disease specialists have a different tendency when it comes to deciding whether they are infected and whether it is safe to rejoin the outside world.

After all, Baird noted that these tests were never designed to act as isolation cards. It’s very hard to rely on results to tell if you’re really still contagious, he says.

“There’s actually a lot more discrepancy than anyone would be happy with,” he says.

A positive antigen test could be basically picking out the remaining viral “garbage”, including “dead virus, mangled virus … viruses that are 90% packed together but won’t really work,” Baird said. And the amount may vary depending on each person’s immune system, form, stage of infection, and so on.

That’s partly because Baird didn’t bother to take a quick test when he recently contracted covid and had to decide when to return to work. A week later, when he felt better, he returned to the office, where everyone had to wear an N95 mask.

Even though it is an imperfect tool, not everyone uses a quick antigen test.

Landon says it’s additional information that can help you figure out how to move forward, especially if people are banking on CDC guidelines to determine if they need to end isolation. That’s because some people will Still Will be contagious after five days, he says.

In fact, a London co-author of the study followed healthcare workers at the University of Chicago who were infected but mostly felt better and went to the test five days later. They found that more than half of them tested positive for antigen even after six days.

Track this with other studies. For example, a study analyzing data from an experimental site in San Francisco during the January Omicron increase suggested that many people were still testing positive five days later. And research by the CDC shows that about half of people were still testing positive for antigen within five to nine days of the onset of symptoms or diagnosis.

“You would be mistaken in terms of caution if you follow the test and say,‘ I’m not going to give up my isolation until my test is negative, ’” he says.

Preliminary data from scientists at Harvard and MIT show that about 25% of people with symptoms had the COVID-19 virus, which can be transmitted eight days after the onset of symptoms or their first test.

But Hey warns that there are considerable differences in research among other factors such as the size of small samples, different populations, how quickly they are tested, who is being tested and how healthy they are.

“It explains a lot of diversity across the study, but I think it’s still quite consistent as a whole search that if you’re antigen positive, you’re more likely to be contagious,” he says.

Some studies have aligned more closely with CDC isolation guidelines, which assume that most people will no longer be contagious after five days. A preprint survey of about 100 vaccinated college students at Boston University found that most were no longer contagious. Five days later.

Dr. Karen Jacobson, an infectious disease specialist at the Boston University School of Medicine and one of the authors of the study, said: There were very few viruses that could be transmitted eight days after the onset of symptoms.

His study found that a negative rapid antigen test on the fifth day was a “perfect” indicator of whether the virus could be transmitted to a lab. In other words, anyone who tested negative five days or more after the initial diagnosis no longer had a detectable virus.

The flip side was that if you were a positive fast [test]”About half of the people still had the culture virus, and half didn’t,” Jacobsen said. “

At the end of the day, if you still test positive, feel better and are symptom-free, then the decision to go out of the world comes into play. If you’re going to spend time with high-risk people, think twice, says Landon.

“If you’re thinking of going to a nursing home to see your grandmother, this is not the time to do it,” she says.

But if you need to do something necessary, don’t feel trapped in your room. Do it but keep your mask on, he adds.

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