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How long are you contagious when you have COVID?

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No one wants to pass COVID-19 on to a loved one (or anyone). But determining how long you’ve been contagious is not an exact science, as it can vary from person to person.

Therefore, you may have a hard time figuring out whether you are putting others at risk. However, there are rules you can follow and things you can know to help protect those around you — as well as alleviate other concerns about your infection.

Here, experts share guidelines for how long you can spread COVID-19 and when it’s most contagious, including with the currently dominant viral strain.

Most people are contagious for about 10 days.

It’s not always clear how long a person is contagious because, like many things with COVID-19, the exact timeline depends on many factors, said Dr. Stuart Ray, professor of medicine and infectious diseases at Johns Hopkins University School of Medicine in Baltimore.

But, Ray said, the conventional wisdom is that you’re contagious and should self-isolate for a full five days after the onset of symptoms — with the first day of symptoms counting as day zero.

But keep in mind that you are not clean after five days.

“It’s often said that you should wear a mask after that to try and protect others because it’s hard to be sure how long you’ve been infectious,” Ray said.

“This period usually lasts up to 10 days,” he added – and again, his first day of symptoms counts as day zero.

Long story short, you are likely to be contagious for about 10 days after your symptoms start. You should self-isolate for the first five days and wear a mask for at least days six to ten.

But you are more infectious at certain points.

The phase where you’re most contagious begins about 48 hours before you test positive and ends five days after your symptoms start, according to Dr. Neha Vyas, a family medicine physician at the Cleveland Clinic in Ohio.. She called this the “period of maximum contagion”.

So you have to be extra careful at this stage – although it’s hard to know if you’re sick before you experience symptoms, which makes the first 48 hours really tricky.

Meanwhile, the amount of time between infection and symptoms has gotten shorter and shorter as COVID-19 mutates, meaning that omicron subvariants like XBB – currently the dominant strain in the US – can spread more quickly. .

If you are exposed to someone who tests positive for COVID-19, you may be able to get tested before you even show symptoms. Or, if you’ve recently attended a crowded internal event, you can audition a few days later. Also, there really isn’t a way to know if you’re infected before you start showing symptoms.

And in the aftermath of your illness, remember that you can still spread COVID-19, so it’s important to wear a mask for at least 10 days.

If you have symptoms after 10 days, you can still spread the virus.

Anyone whose symptoms persist after day 10 and who continue to test positive is likely to be able to pass the virus to other people. If it’s you, keep wearing a mask and avoiding closed spaces and events, Ray said.

“IIf you are immunocompromised or have had an actual illness [severe] COVID infection… so you could still be contagious for 20 days” after the onset of symptoms, he added Vyas.

Long periods of contagion like this are rare, she emphasized. But if you fall into one of these two categories, talk to your doctor for further guidance.

If possible, you should isolate yourself from other people in your home for five days.  After that, mask wearing is important.
If possible, you should isolate yourself from other people in your home for five days. After that, mask wearing is important.

Home antigen tests are a good way to find out if you are still contagious.

It’s not uncommon for someone to test positive on a lab test for weeks after a COVID-19 infection, “but it would be very unusual for someone to test positive for weeks on an antigen test,” Ray said.

Antigen tests are the kind you might have bought at the drugstore (from brands like iHealth) or received from the government (which is still sending out free tests, by the way).

Ray added that a positive antigen test correlates with the virus’s ability to grow and infect. So if you have a positive antigen test, you are probably contagious.

And it works the other way around too.

“We usually say if your symptoms completely resolve and you test negative, you are unlikely to be infectious,” Ray said.

If you want to be more cautious, you can have two COVID tests.

If you’re past the 10-day mark and no longer have symptoms, but you’re anxious about possibly spreading the virus to a loved one, there are things you can do.

“You can do two COVID tests 48 hours apart,” Vyas said. “If both are negative, you can [be] pretty sure you are no longer contagious.

She added that most people won’t need to do this as long as they follow the 10-day guideline. But if you’re nervous about transmitting the virus, this is a good tactic.

If you live in a house with other people, you should do what you can to protect them.

“If possible, a contagious individual should use a separate bedroom and bathroom, especially during this five-day period. [after symptoms begin]”, said Dr. Ali Khan, chief medical officer at Oak Street Health.

When this is not possible, wear a well-fitting mask – preferably an N95 or KN95 – around other people in your home.

Khan added that an infected person should have their own cutlery and sheets and that they should avoid high-touch items.

“Don’t forget to wash your hands frequently,” Khan said – and that goes for people who aren’t infected, too.

Finally, to protect yourself and your loved ones, make sure you’re up to date on your COVID-19 boosters.

“It’s definitely not too late to get COVID-19 and flu shots as they still reduce severe symptoms even if you do get disease,” Khan said.