Dr. Nirav R. Shah, commissioner of the New York state Department of Health, said the regulation is intended to protect patients from getting the flu from healthcare workers.
Influenza can be severe and cause death in patients with underlying medical conditions.
"Getting vaccinated is the best way to protect against influenza, and it is important for individuals who come in contact with patients to be vaccinated to help prevent the spread of flu," Shah said in a statement.
The New York State Department of Health regulatory requirement applies to healthcare settings regulated by the agency. The settings include general hospitals, nursing homes, diagnostic and treatment centers, certified home health agencies, long-term home health care programs, acquired immune deficiency syndrome, home care programs, licensed home care service agencies, limited licensed home care service agencies and hospices.
The mask requirement remains in effect until the commissioner declares influenza is no longer prevalent in the state.
Notable deaths of 2014 [PHOTOS]