US health authorities on Monday halved the recommended isolation time for people with asymptomatic COVID-19 infections from 10 to 5 days, with a surge of cases causing travel chaos and threatening wider social disruption.

"The omicron variant is spreading quickly and has the potential to impact all facets of our society," the Centers for Disease Control and Prevention's director Rochelle Walensky said in a statement announcing the change.

"These updates ensure people can safely continue their daily lives."

• No ‘panic’, but coronavirus to ‘overrun’ some US hospitals, says Biden

The CDC recommendations, which are non-binding but closely followed by US businesses and policymakers, suggested that the 5-day isolation period be "followed by 5 days of wearing a mask when around others."

• Israeli hospital launches first test of second COVID-19 booster

The agency said the new guidelines were "motivated by science," which had demonstrated that the majority of COVID-19 transmission occurs early in the course of illness, generally 1 to 2 days prior to the onset of symptoms and in the 2 to 3 days after.

The CDC also updated recommendations for individuals exposed to COVID-19 who are either unvaccinated or booster-eligible but have yet to get one.

For these populations the CDC said it "now recommends quarantine for 5 days followed by strict mask use for an additional 5 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," the CDC said.

The updates came as the highly transmissible omicron strain has sent cases skyrocketing across the United States, once again disrupting lives and a global economy battered by almost two years of the pandemic.

• Philippines urged to avoid lockdowns despite omicron

With omicron now the country's dominant strain, more than 200,000 daily cases were recorded over the past two days, quickly approaching records set last January.

• Scrapped flights, resurgent COVID deliver Christmas gut punch

President Joe Biden earlier in the day said some US hospitals could be "overrun" but that the country is generally well prepared to meet the latest surge and Americans need not "panic."

Biden stressed that the rapid spread of omicron would not have the same impact as the initial outbreak of COVID-19 or the delta variant surge this year.

Walensky emphasized that "prevention is our best option."

"Get vaccinated, get boosted, wear a mask in public indoor settings in areas of substantial and high community transmission, and take a test before you gather," she said.

RELATED VIDEO

Watch more in iWantv or TFC.tv