NEW YORK (AP) — According to federal officials, concerns that a new COVID-19 wave could overwhelm understaffed U.S. hospitals. On Thursday, officials said they have loosened rules that call on health care workers to stay out of work for 10 days if they test positive.

The isolation time of health care workers can be cut to five days, or even fewer, if there are severe staffing shortages, according to the new Centers for Disease Control and Prevention guidance. Those workers will now be allowed to come back to work after seven days if they test negative and don’t have symptoms.

“As the health care community prepares for an anticipated surge in patients due to omicron, CDC is updating our recommendations to reflect what we know about infection and exposure in the context of vaccination and booster doses,” CDC Director Rochelle Walensky said in a statement.

CDC officials have advised that in calculating the 10-day isolation period, the first day should be the first full day after symptoms first developed or after a positive test. If a person develops symptoms sometimes after a positive COVID-19 test, the quarantine period must restart, beginning one day after the symptoms develop.

“Our goal is to keep health care personnel and patients safe, and to address and prevent undue burden on our healthcare facilities,” she added. Isolation is designed to keep infected people away from uninfected people, to prevent the further spread of the virus.