Essential workers in New York State may, at the discretion of their employers, be allowed to return to work five days after testing positive for the coronavirus under a new policy announced by Gov. Kathy Hochul on Friday.The move halves the amount of time such workers currently have to isolate after a positive test result. It comes as tens of thousands of residents of the state are sidelined at their jobs and the number of virus cases linked to the Omicron variant soars.The measure applies to workers who are fully vaccinated, don’t have a runny nose or disruptive cough that impedes mask-wearing, and haven’t had a fever for 72 hours. Testing isn’t required to return to work, and employees must stay masked while on the job. If not at work, they must continue to isolate and avoid public places for 10 days, according to the new policy.On Friday, New York State reported 44,431 new virus cases out of about 360,000 people tested, an increase of nearly 5,600 new cases day over day and the highest single-day figure since the pandemic began.Ms. Hochul’s decision coincided with growing evidence that while highly transmissible, the Omicron variant often results in milder illness than Delta and other earlier variants of the virus.The surge in cases has strained the health care systems across the country, as more people require care and hospital workers who become infected are forced into isolation themselves or must stay home to care for sick family members.The Centers for Disease Control and Prevention on Thursday recommended cutting the isolation period for health care workers who have tested positive from 10 to seven days if they have no symptoms and test negative before returning to work.But public health experts have said that ranks of workers in other important industries could soon be severely depleted because of a combination of rampant illness and isolation requirements.Ms. Hochul clearly had those warnings in mind in announcing her decision to allow for a shorter isolation period for essential workers, which include a broad spectrum of health care workers, teachers, trash haulers, restaurant employees and others. An outline of the new policy cited a study showing that vaccine recipients had a shorter duration of infection.“We want to make sure that our critical work force who we’ve relied on from the beginning — and my heart goes out to them filled with gratitude — that our workers can get back,” she said at a news conference. “You’re the ones that got us through the first many months of anxiety. We need you again. We need you to be able to go to work.”