Illinois' health department said it will adopt the Centers for Disease Control and Prevention's revised guidelines on isolation and quarantine for COVID.
The action by the CDC cut in half the recommended isolation time for Americans who are infected with the coronavirus but have no symptoms. The CDC similarly shortened the amount of time people who have come into close contact with an infected person need to quarantine.
Under the new guidance, people who test positive but show no symptoms would only need to isolate five days instead of 10, but must continue to mask for five after isolation ends.
The recommendation includes those who are unvaccinated.
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The CDC also reduced the amount of time needed to quarantine for those exposed to someone with COVID from 10 days to five, if they are showing no symptoms. These individuals would also need to continue masking for an additional five days after quarantine ends.
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.
"Both updates 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," IDPH said in a statement.
Still, the new CDC guidance has raised questions about how it was crafted and why it was changed now, in the middle of another wintertime spike in cases, this one driven largely by the highly contagious omicron variant.
The CDC defended its decision to shorten isolation time, saying that most COVID transmission has been shown to occur in the one-to-two days prior to symptoms appearing, and the following two-to-three days after they appear.
Dr. Emily Landon of UChicago Medicine was asked to break down the new guidelines for NBC 5, and to explain the steps that residents need to take when adhering to the rules.
“When you’re completely better, with no more fever, then as long as you’ve been in isolation for at least five days, once you’re better you can come out of that isolation and go back to spending time without people, or go back to your job or other things, but you need to wear a good, high-quality mask until at least ten days are up,” she said.
Landon cautioned residents not to necessarily rely on that exact timeline, saying that in many cases patients can remain contagious for a longer time period, and that is why wearing a mask is critical.
“Having to wear masks after the five days is essential to keeping your family and other people safe,” she said.
Another criticism of the new guidelines is that they allow people to leave isolation without getting tested to see if they are still infectious.
“It’s frankly reckless to proceed like this,” Dr. Eric Topol, founder and director of the Scripps Research Translational Institute, told NBC News. “Using a rapid test or some type of test to validate that the person isn’t infectious is vital.”
Some physicians have also pointed out that much of the science on how long COVID patients can remain contagious was done prior to the omicron variant becoming the dominant strain of the virus in the United States, and that it isn’t clear whether the viral load carried by patients decreases at the same rate in those infected by omicron.
While the new guidance didn’t provide new rules for children and schools, Landon said the same approach to vaccination and quarantine should be in place.
“If you are a child who hasn’t been boosted and you got vaccinated more than six months ago, then you absolutely need to be doing the full five days of staying home if you’ve been exposed,” she said.