By Louisa Moller

BOSTON (CBS) — The CDC now says all Americans who test positive for COVID-19 can cut their isolation time in half from 10 days to five days if they are asymptomatic and wear a mask for the following five days.

“The Omicron variant is spreading quickly and has the potential to impact all facets of our society. CDC’s updated recommendations for isolation and quarantine balance what we know about the spread of the virus and the protection provided by vaccination and booster doses,” CDC Director Rochelle Walensky said in a statement released Monday afternoon.

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The CDC said “the change is motivated by science” and the majority of SARS-CoV-2 transmission occurs early in the course of illness, generally in the 1-2 days prior to the onset of symptoms and the two to three days after.

Federal health officials also updated quarantine guidelines for unvaccinated individuals who come in contact with covid positive people. Those individuals are recommended to quarantine for five days and then wear a mask for an additional five days.

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Tufts Medical Center Epidemiologist Dr. Shira Doron said the new isolation guidance is reasonable, especially for the vaccinated.

“Those viral loads fall very quickly, presumably as that vaccine-induced immunity, those neutralizing antibodies kick in,” Doron said.

The update came just days after the CDC issued similar isolation guidance but strictly for health care workers. Tufts Medical Center had 118 employees out with Covid-19 Monday and was beginning to implement the new protocols although none of those employees had returned to work early.

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Monday, hundreds of Massachusetts National Guard began training to deploy to local hospitals to ease critical staffing shortages. Monday also marked the deadline to cancel or postpone non-emergency procedures in Massachusetts hospitals.

Louisa Moller