The Centers for Disease Control and Prevention on Monday shortened the recommended time for isolation for asymptomatic Americans infected with the coronavirus disease to five days. Previously, the agency had recommended that patients isolate for 10 days from when they were tested for the virus.

At the end of five days, patients without symptoms can return to normal activities but must wear a mask around others for at least five more days.

The health authorities also shortened the recommended time for people to quarantine if they are exposed to the virus to five days if they are vaccinated. Those who are fully vaccinated and have received booster dose may not need to quarantine at all, the Centers for Disease Control and Prevention said.

People who have been exposed to Covid-19 are encouraged to wear masks around others for 10 days.

The Centers for Disease Control and Prevention did not recommend that people take rapid Covid tests before coming out of isolation. Dr Aaron Glatt, a physician in New York who is a spokesperson for the Infectious Diseases Society of America, said the risk of spread of the virus does drop substantially after five days, but it does not disappear for everyone, AP reported.

“If you decrease it to five days, you’re still going to have a small but significant number of people who are contagious,” he said.

The new recommendations, Centers for Disease Control and Prevention Director Rochelle Walensky said, “balance what we know about the spread of the virus and the protection provided by vaccination and booster doses”.

The updated guidelines come at a time when the US is recording a surge of infections that threatens to swamp the healthcare system. On Monday, the country recorded 4,72,112 new coronavirus cases as many states reported a backlog in figures after Christmas celebrations.

Last week, the Centers for Disease Control and Prevention had said that the new Omicron variant accounts for 73.2% of cases in the country. The agency had also updated its guidance for health care workers, saying that those with Covid-19 who show no symptoms or have mild symptoms can return to work after seven days if they test negative for infection at that point.

Staff shortages have led to thousands of flights being cancelled globally. As health workers contract the infection, experts have warned of an unmanageable crush of patients, The Guardian reported.

Lindsay Wiley, an American University public health law expert, told AP the new guidance “is going to be perceived as coming in response to pressure from business interests”.