Washington, Mar 1 (IANS): Health experts have urged the people not to let down guard against Covid-19 entirely as the US Centers for Disease Control and Prevention (CDC) has updated guideline allowing most Americans to unmask indoors.

Americans should be ready to return to masking if the science changes, experts have warned, Xinhua news agency reported.

More than 70 per cent of Americans should be able to remove their masks indoors, including inside schools, under the new CDC guideline announced on Friday.

According to the new guideline, the CDC determines the Covid-19 community level of various regions by looking at three metrics -- hospital beds being used, hospital admissions, and the total number of new Covid-19 cases.

Using these data, the Covid-19 community level is classified as low, medium, or high.

Under the updated guidance, more than 70 per cent of the US population is in a location with low or medium Covid-19 community levels. For those areas, there is no recommendation for indoor masking unless people are at high risk for severe illness.

Health experts said the new move of the CDC makes sense as the vast majority of vulnerable Americans are fully vaccinated, and new cases, hospitalizations and deaths caused by the Omicron variant continue to drop.

However, some health experts warned the new metrics could lead to a rise in cases and hospitalizations. Others worry that masking guidelines may be difficult to reimpose if another variant of concern arrives and appears to evade Omicron-generated immunity.

CDC Director Rochelle Walensky warned Americans not to let down their guard entirely.

"We want to give people a break from things like masking when our levels are low, and then have the ability to reach for them again should things get worse in the future," she said.

"We need to be prepared, and we need to be ready for whatever comes next," Walensky said.

The country is now averaging about 75,000 daily new cases, a decrease of 37.7 per cent compared with the previous week, according to the latest CDC weekly report.

The number of new hospital admissions in the country is about 6,000 each day, a 29.9 per cent decrease from the prior 7-day average.

Currently about 1,700 new deaths are reported in the country daily, a decrease of 18.8 percent compared with the previous week, CDC data showed.