The Centers for Disease Control and Prevention (CDC) on Thursday released updated guidance for isolation and quarantine, cutting the length of time health care workers need to do so amid an increase in cases of the Omicron coronavirus variant. As of Monday, Omicron makes up at least 73 percent of new cases in the United States, according to the CDC. The new guidance reduces isolation time for health care workers with COVID-19 from 10 to 7 days, provided they are asymptomatic and can present a negative test. That isolation time can be cut further if there are staffing shortages, the CDC said. Health care workers who are fully vaccinated and have received a booster shot do not need to quarantine at home following high-risk exposure. The updated guidance only applies to health care workers and may still be revised as officials receive more information on the Omicron variant. The CDC said the new guidelines are meant to limit …