covid symptoms

How Long Are You Contagious With COVID and When Are You Most Likely to Spread It?

NBCUniversal Media, LLC

For those who contract COVID, particularly with the spread of the ultra-transmissible BA.5 omicron subvariant, it's not just while you're experiencing symptoms that you can be contagious, experts say. In fact, the now-dominant variant may even be keeping people positive for longer.

The latest guidance from the Centers of Disease Control and Prevention recommends people who contract COVID-19 isolate for at least five days, followed by five days of strict mask use.

Despite the length of positivity and the contagiousness of the BA.4 and BA.5 omicron subvariants, Chicago Department of Public Health Commissioner Dr. Allison Arwady said she doesn't anticipate changes to isolation or quarantine protocols. She did note, however, 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 last week.

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. Even with the latest subvariants, the isolation guidance remains the same.

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 cases.

A recent 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.

As a precaution, those out of the five-day isolation window should partake in strict mask use for an additional five days, guidance stated.

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."

Even still, some health experts are warning that reinfection can occur even faster with the latest variants.

"We don't know know exactly how soon, but people have been recorded to get the infection as soon as four weeks after having a previous infection," said Dr. Sharon Welbel, director of hospital epidemiology and infection control at Cook County Health.

Welbel said that current reinfections could be related to either waning immunity from a previous infection or from vaccinations, depending on if a person has had a booster shot and when. For that reason, Welbel said it's possible some could contract the virus again even earlier than one month post-infection.

"It could even be sooner," she said. "I would think, you know, depending on one's immune system, on their level of antibodies - to either the vaccine or a previous infection - but because, you know, we do not become immune to this from our vaccine or from a previous infection to any of the variants that we have already experienced ... I don't see why somebody couldn't even get it as soon as two weeks later. Have I been seeing that? No. Have I been seeing that talked about? No. But definitely have seen people within a month."

Contact Us