A system comprising a portable unit which can be temporarily placed outside a patient room comprising a processor, memory, a speaker or voice generator, and programming to allow an authorized user to select (A) a disease or medical condition which corresponds to preprogrammed simulated voice warnings, for example “wash hands,”“wear gown,”“wear gloves,”“wear mask,”“dispose of gown,”“use hand sanitizer,”“wash hands with soap and water after removing protective clothing,” and combinations of said voice warnings; or (B) one or more of said preprogrammed voice warnings; a room entry detector programmed to activate the simulated voice warnings, the system configured so that when entry to the room is detected, one or a combination of the simulated voice warnings is emitted by the system.