The Centers for Disease Control and Prevention on Monday said it was now recommending that people isolate or quarantine five days — down from 10 — after testing positive for COVID-19 but are asymptomatic or have been exposed to someone with the coronavirus.

“Isolate” means to stay away from other people and “quarantine” means to stay at home, according to the CDC.

“Given what we currently know about COVID-19 and the Omicron variant, CDC is shortening the recommended time for isolation from 10 days for people with COVID-19 to 5 days, if asymptomatic, followed by 5 days of wearing a mask when around others,” the CDC said.

“The change is motivated by science demonstrating that the majority of SARS-CoV-2 transmission occurs early in the course of illness, generally in the 1-2 days prior to onset of symptoms and the 2-3 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.

As for people who have prolonged exposure to people who have COVID-19, the CDC added: “For people who are unvaccinated or are more than six months out from their second mRNA dose (or more than 2 months after the J&J vaccine) and not yet boosted, CDC now recommends quarantine for 5 days followed by strict mask use for an additional 5 days.

“Alternatively, if a 5-day quarantine is not feasible, it is imperative that an exposed person wear a well-fitting mask at all times when around others for 10 days after exposure. Individuals who have received their booster shot do not need to quarantine following an exposure, but should wear a mask for 10 days after the exposure.

“For all those exposed, best practice would also include a test for SARS-CoV-2 at day 5 after exposure. If symptoms occur, individuals should immediately quarantine until a negative test confirms symptoms are not attributable to COVID-19.”

— Robert Moran