Omicron Variant

What is the Incubation Period for the Omicron Variant and How Long Are You Contagious?

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If you test positive for coronavirus or are exposed to someone who has during the omicron surge, what is the incubation period and how long could you be contagious?

The Centers for Disease Control and Prevention issued new guidance last month, shifting the timing for isolation and quarantine as some experts say the time frame when people are most contagious is earlier.

"It is taking less time from when someone is exposed to COVID to potentially develop infection. It is taking less time to develop symptoms, it is taking less time that someone may be infectious and it is, for many people, taking less time to recover. A lot of that is because many more people are vaccinated," Chicago Department of Public Health Commissioner Dr. Allison Arwady said previously.

The Illinois Department of Public Health said the changes from the CDC come as "the omicron variant continues to spread throughout the U.S. and reflects the current science on when and for how long a person is most infectious."

The CDC says that its guidelines were updated to reflect growing evidence that suggests transmission of COVID-19 often occurs one to two days before the onset of symptoms and during the two to three days afterward. 

"This has to do with data from the CDC that really showed after seven days there's virtually no risk of transmission at this point," Arwady said. "And in that five-to-seven-day window, you know, there's some depending on whether people have been vaccinated, underlying conditions, etc., but the risk drops a lot and the feeling is that in the general population, combined with masking, etc. the risk really is very low."

For those without symptoms, CDC guidance states they are considered contagious at least two days before their positive test.

The CDC states that anyone who may have been exposed to someone with COVID should test five days after their exposure, or as soon as symptoms occur.

"If symptoms occur, individuals should immediately quarantine until a negative test confirms symptoms are not attributable to COVID-19," the guidance states.

IDPH Director Dr. Ngozi Ezike said that incubation times could be changing due to omicron, but those who test early should continue testing even if they get negative results.

"We might be learning that the time of incubation might be a little shorter. So maybe you'd be testing at two days," Ezike said. "Obviously if you're symptomatic, you test right away. But you know, if you want to test at two days, but that negative test... the two days should not make you think, 'Oh good, I'm clear,' you know? You might want to test again and of course symptoms you cannot ignore - scratchy throat, headaches, all kinds of symptoms - anything new can be a symptom of this new illness."

According to earlier CDC guidance, COVID symptoms can appear anywhere from two to 14 days after someone is exposed to the virus.

Anyone exhibiting symptoms should get tested for COVID-19.

Under the guidance, those who have been within six feet of someone with COVID for a cumulative total of at least 15 minutes over a 24-hour period should quarantine for five days if unvaccinated, or if they are more than six months out from their second vaccine dose.

Once that period ends, they should partake in strict mask use for an additional five days.

Those who are both fully vaccinated and boosted do not need to quarantine if they are a close contact of someone with COVID, but should wear a mask for at least 10 days after exposure. The same goes for those who are fully vaccinated and not yet eligible for their booster shot.

People who are positive for COVID should stay home for five days, the CDC said.

At the end of the period, if you have no symptoms, you can return to normal activities but must wear a mask everywhere — even at home around others — for at least five more days.

If you still have symptoms after isolating for five days, stay home until you feel better and then start your five days of wearing a mask at all times.

Illinois' health department said it will adopt the CDC revised guidelines on isolation and quarantine for COVID.

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