A medical worker administers a COVID-19 test at a new testing site at the Times Square subway station in New York City on Monday.

Scott Heins/Getty Images

hide caption

toggle caption

Scott Heins/Getty Images

A medical worker administers a COVID-19 test at a new testing site at the Times Square subway station in New York City on Monday.

Scott Heins/Getty Images

People who test positive for COVID-19 only need to isolate themselves for 5 days if they don’t show symptoms, the Centers for Disease Control and Prevention said Monday. This cuts in half the earlier recommendation of 10 days of isolation.

Data shows that the majority of COVID-19 transmission “occurs early in the course of the illness,” the CDC explained — generally in the one or two days before symptoms begin, and two or three days after.

“Therefore, people who test positive should isolate for 5 days and, if asymptomatic at that time, they may leave isolation if they can continue to mask for 5 days to minimize the risk of infecting others,” the CDC said.

The CDC has also updated its recommended quarantine period for people exposed to the virus. It says the unvaccinated should quarantine for 5 days, followed by 5 days of “strict mask use.” Exposed people who are more than 6 months past their second dose of Pfizer or Moderna, or 2 months out from a Johnson & Johnson vaccine, should also quarantine for 5 days.

Alejandro Brown receives a COVID-19 vaccine from a health care worker at a drive-thru site in Miami on Dec. 16.

Joe Raedle/Getty Images

hide caption

toggle caption

Joe Raedle/Getty Images

Alejandro Brown receives a COVID-19 vaccine from a health care worker at a drive-thru site in Miami on Dec. 16.

Joe Raedle/Getty Images

People who have gotten their booster shot don’t need to quarantine after exposure, but should wear a mask for the next 10 days.

“The Omicron variant is spreading quickly and has the potential to impact all facets of our society,” said CDC Director Dr. Rochelle Walensky. “CDC’s updated recommendations for isolation and quarantine balance what we know about the spread of the virus and the protection provided by vaccination and booster doses. These updates ensure people can safely continue their daily lives.”

The new guidance comes days after the CDC loosened rules for how long health care workers should isolate after infection with COVID-19, from 10 days to 7 days. If there were staffing shortages, that isolation time could be further reduced.

The next day, New York officials followed suit, reducing to 5 the number of days for health care workers to isolate after having COVID-19. On NPR’s Morning Edition Monday, Dr. Anthony Fauci praises the move.

Five days of quarantine should be enough for health care workers, Fauci said, adding: “That’s going to be under consideration of whether or not we want to diminish it” for the general public.

In the United States as of Monday, 242 million people have received at least one dose of a COVID-19 vaccine, 205 million are fully vaccinated, and 66 million have received a booster, according to the CDC’s COVID data tracker.