Nurses and other UMass Memorial Medical Center staff members who have not been vaccinated against the flu have been told that they must wear a mask on the job to protect patients from being infected during a hospital stay. The change at UMass Memorial has angered some nurses who say the hospital is trying to shame them into getting a flu shot. "They're just bullying people," said Ellen Smith, who works in intensive care at the health system's university campus. Smith, who was wearing a mask Friday, said she has not gotten a flu shot during 20 years as a nurse.