covid symptoms

When Are You Most Contagious With COVID? Here's a Timeline

Patients could test positive for COVID months after recovering, according to health officials

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As COVID-19 cases continue to climb and new subvariants emerge, some may be wondering how long the virus can linger.

Under revised guidance from the Centers of Disease Control and Prevention, people who contract COVID-19 are advised to isolate for at least five days. After you have ended isolation, you'll also need to wear a mask through day 10, per the guidelines. When the isolation period is over, you should still avoid being around people who are most at-risk until at least day 11.

In regard to two recent strains, the BA.4 and BA.5 subvariants, Chicago Department of Public Health Commissioner Dr. Allison Arwady noted that some people are staying positive longer.

"I wouldn't say the incubation period is shorter. ... It's been getting shorter compared to what the original was, but we are seeing people often have just upper respiratory symptoms or having a cold, they're having sore throat sometimes, they're having fever or not seeing a lot of that severe illness - especially in people who are up to date with vaccine because the secondary part of your immune system kicks in and helps - but we're seeing people they can stay positive for a little longer," Arwady said this summer.

The risk of spreading COVID drops significantly after Day 10, including for those who have lingering symptoms.

"If you're mostly feeling well, especially if what is still kind of lingering is a cough or a little bit of cough tends to be the last thing to go away after any virus, it is unlikely that you are still spreading disease," Dr. Arwady previously said.

Recognizing that 95% of Americans 16 and older have acquired some level of immunity against COVID-19, the CDC in mid-August announced it was easing social distancing requirements and no longer encouraging Americans to quarantine if they come into close contact with an infected person.

Generally, a person with COVID-19 is considered infectious starting two days before they develop symptoms, or two days before the date of their positive test if they do not have symptoms, according to the CDC.

As long as their symptoms have improved, most people are no longer contagious five days after they first show symptoms.

However, that's not true in all instances.

A Boston University study revealed that just 17% of people were likely still contagious six days after their first positive tests. But a University of Chicago Medical Center study published earlier this year contradicted CDC recommendations, finding more than 40% of vaccinated health care workers still tested positive for COVID-19 five to 10 days after their symptoms began.

According to the CDC, data suggests patients with mild-to-moderate COVID-19 remain infectious no longer than 10 days after symptom onset. Those with severe-to-critical illness stemming from a COVID infection likely aren't infectious 20 days after symptoms first begin.

While they likely won't be infectious after that, patients could test positive for COVID months after recovering.

PCR tests are "very sensitive," Arwady previously said, adding they can "stay positive for a long time."

"They keep picking up dead virus in your nose for sometimes for weeks, but you can't grow that virus in the lab," she stated. "You can't spread it, but it can be positive."

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