Germicidal UV light trial shows promise in reducing respiratory infections in aged care

A groundbreaking study conducted in South Australia has explored the potential of germicidal ultraviolet (GUV) light appliances to reduce acute respiratory infections (ARIs) in long-term care facilities for older adults.

The randomised clinical trial, published in JAMA Internal Medicine, offers encouraging insights into an innovative approach to bolster infection control in aged care settings, a sector where respiratory viruses like influenza, respiratory syncytial virus, and SARS-CoV-2 pose significant risks.

The study, known as the Prevention of SARS-CoV-2 Transmission in Residential Aged Care Using UV Light (PETRA), was conducted across four long-term care facilities in metropolitan and regional South Australia from August 2021 to November 2023. It involved 211,952 bed-days and recorded 596 ARIs, with 475 occurring during intervention or control periods. The trial aimed to assess whether GUV appliances, installed in communal areas such as corridors, lobbies, and dining rooms, could reduce the incidence of ARIs among residents.

GUV appliances work by using ultraviolet light to neutralise airborne viral, bacterial, and fungal pathogens as air circulates through a disinfection zone.

This technology, which has shown efficacy in laboratory settings against pathogens like influenza and coronaviruses, offers a low-cost, non-disruptive complement to existing infection control measures. Unlike traditional methods such as mask-wearing and physical distancing, which can be challenging to implement consistently, particularly in memory support units, GUV appliances require no changes to staff or resident behaviour.

The trial employed a robust, double-crossover, cluster-randomised design, dividing each facility into two zones of approximately 44 beds each. Zones were assigned either active GUV appliances (intervention) or inactive appliances (control) for six-week periods, followed by two-week washout phases, over seven cycles spanning 110 weeks. This extended duration allowed researchers to capture data across two complete winter respiratory virus seasons, providing a comprehensive view of the intervention’s impact.

Results showed that while GUV appliances did not significantly reduce the incidence rate of ARIs per zone per cycle (4.17 infections in the control arm versus 3.81 in the intervention arm, with an incidence rate ratio of 0.91, P = .33), a secondary analysis revealed a significant reduction in total ARIs over time.

Using time-series modelling, the intervention group recorded 0.319 fewer infections per week, equating to a 12.2% reduction compared to the control group (P = .004). This reduction translates to an estimated 92 fewer ARIs per 1,000 residents annually, a meaningful outcome for aged care facilities where respiratory infections can lead to high rates of hospitalisation and mortality.

Notably, the trial included a sub-analysis of memory support units, where infection control measures are often less effective due to residents’ behavioural and psychological challenges. Excluding these units from the analysis further strengthened the findings, with the intervention arm showing 0.41 fewer infections per week (P < .001). This suggests that GUV appliances may offer particular benefits in settings where standard precautions are difficult to enforce.

The study’s findings are especially relevant given the heightened focus on infection control following the COVID-19 pandemic. While traditional measures like hand hygiene and masks remain critical, they do not fully address airborne transmission, a key driver of respiratory virus spread in residential care settings. GUV appliances, with their ability to sterilise air in communal spaces, present a practical and scalable solution to enhance resident safety without disrupting daily operations.

Despite the promising results, the study faced limitations, including the inability to collect environmental samples due to pandemic-related restrictions and challenges in confirming the cause of all ARIs through laboratory testing.

Additionally, the movement of residents and staff between zones may have introduced some cross-contamination. However, the trial’s pragmatic design, conducted in real-world aged care settings, enhances its applicability to similar facilities across Australia and beyond.

The PETRA study marks a significant step forward in exploring innovative infection control strategies for aged care. While the reduction in ARI incidence per cycle was not statistically significant, the overall decrease in infections over time suggests that GUV appliances could play a valuable role in protecting vulnerable residents. As aged care facilities continue to navigate the challenges of seasonal and emerging respiratory viruses, integrating GUV technology into existing infection control frameworks could offer a cost-effective and sustainable approach to safeguarding resident health.

Further research is needed to optimise the deployment of GUV appliances, including their integration into heating, ventilation, and air conditioning systems, and to assess their cost-effectiveness. However, these initial findings provide a compelling case for considering GUV as part of a comprehensive strategy to enhance infection prevention in aged care, offering hope for healthier and safer environments for older adults.