US health authorities on Monday announced that quarantine periods for asymptomatic coronavirus patients would be shortened from 10 to five days.

The Centers for Disease Control and Prevention (CDC) cited evidence that those infected with the virus were most infectious during the two days before and then three days after symptoms developed. 

The CDC has also updated the recommended quarantine period for people exposed to COVID-19 who are unvaccinated or who are due for a booster but have not yet received one.

For those individuals, the CDC said it "now recommends quarantine for five days followed by strict mask use for an additional five days."

Individuals who have received a booster shot do not need to quarantine, but should wear a mask for the same 10-day period.

The CDC guidelines are non-binding but are closely followed by US businesses and policymakers.

Why did the CDC ease isolation rules?

There has been surge in cases in the US as a result of the omicron variant. But there are concerns over the affect quarantine periods are having on various industries.

CDC director Rochelle Walensky said that the response to the omicron variant was being balanced with the level of illness it was causing.

"Not all cases are going to be severe. In fact many are going to be asymptomatic," Walensky said.

"We want to make sure there is a mechanism by which we can safely continue to keep society functioning while following the science."

Last week, the agency also eased rules for those working in health care sector and said those who tested negative and did not have symptoms could return to work after seven days.

What is the COVID situation in the US?

The changes come as the highly transmissible omicron strain has spread across the United States and become the country's dominant strain.

More than 200,000 daily cases of coronavirus infection were recorded in the United States over the past two days.

US president Joe Biden said on Monday that hospitals could be "overrun" but that Americans do not need to panic as the country is well-prepared to deal with the latest rise in cases.

Biden added that omicron's spread would not have the same impact as the initial outbreak of the pandemic or the waves of infection caused by the spread of the delta variant of the coronavirus.

sdi, kb/fb (AP, AFP)