The potential effectiveness of far-UVC (222 nm) in preventing infections in long-term care facilities: a six-month nonrandomized controlled phase II trial.

Objectives: The objectives of this study were to assess the potential effectiveness of far-UVC (222 nm) in reducing hospital-treated infections, antibiotic prescriptions, and mortality in long-term care facilities (LTCFs), as well as to evaluate the rationale for a future randomized controlled trial (RCT). Design: A six-month, nonrandomized, controlled, three-arm Phase II trial was conducted in LTCFs in Denmark. Facilities were allocated in a 10:1:1 ratio to usual care, far-UVC in common rooms, and far-UVC in common and residents' rooms. The trial was conducted between November 2024 and April 2025. The primary outcome was LTCF-acquired infections treated in hospitals. Results: The study included 12 LTCFs with a total of 635 residents. In the usual care group (n = 470), 600 hospital-treated infections were identified with a incidence rate (IR) of 86.2 per 10,000 resident-days. In the common rooms group (n = 76), 12 infections were identified with a IR of 10.4 per 10,000 resident-days and an adjusted incidence rate ratio (aIRR) of 0.12 (95% CI: 0.04-0.34). In the common and residents' rooms group (n = 89), 78 infections were identified with a IR of 59.1 per 10,000 resident-days and an aIRR of 0.69 (95% CI: 0.23-2.07). The aIRR for total antibiotic prescriptions was 0.52 (95% CI: 0.29-0.96) in the group with lamps in common rooms and 0.83 (95% CI: 0.50-1.37) in the group with lamps in common and residents' rooms. Conclusions: Far-UVC potentially reduces hospital-treated infections and antibiotic prescriptions in LTCFs, but these results should be considered preliminary until confirmed by an RCT.