Far-UVC (222 nm) light devices have shown potent anti-viral activity in vitro, but efficacy has not been proven clinically. This presentation describes the protocol for a pragmatic cluster randomized trial evaluating the effectiveness of far-UVC light for the prevention of respiratory viral illnesses in long-term care homes. Preparations are being made to launch the second phase of the trial, to introduce an updated far-UVC light device and an additional site.