As of Oct. 10, all staff at Massachusetts' long-term care facilities will be required to be fully vaccinated against COVID-19, the governor's office said Wednesday. “COVID-19 vaccination is the most effective method for preventing infection and serious illness from the virus, and staff at long-term care facilities and other health care providers serving vulnerable populations are critical in efforts to protect older residents,” the administration said. Massachusetts has 378 level one to level three skilled nursing facilities and two soldiers' homes, who serve older adults more vulnerable to COVID-19, that will be covered by the mandate.The administration said Wednesday that 155 of those facilities had less than 75 percent of their staff fully vaccinated as of Monday.All unvaccinated personnel are to receive the first dose of a two-dose series by Sept. 1 and be fully vaccinated by Oct. 10, the state said.Personnel includes all individuals employed directly or by contract by an LTC provider, the state said. The union that represents nearly 3,000 nursing home members in the state, appeared to question the move. "Vaccination is an important tool to help us move forward, yet at a time when nursing home workers are short-staffed and healing from the trauma they have experienced, they should not suffer economic hardship, including termination, due to delaying vaccination," the statement from 1199SEIU executive vice president Tim Foley said."Nursing workers should be afforded a full and fair opportunity to make an informed decision about the vaccine," the statement said. The U.S. Department of Veterans' Affairs imposed a vaccine mandate for its workforce, which serves a large number of older adults.In Massachusetts, the state auditor and treasurer's office will require employees to show proof of vaccination or submit to weekly testing when they return to in-person work.The requirement will allow exemptions for those with medical restrictions or sincerely held religious beliefs.