High efficiency particulate air filters to prevent winter respiratory infections in care homes:the AFRI-c cluster randomized clinical trial

<div><b>Importance</b>:</div><div>Portable high efficiency particulate air (HEPA) filters effectively remove airborne microbes.</div><div><br/></div><div><b>Objective</b>:</div><div>To investigate whether HEPA filters reduce respiratory infection episodes in care home residents.</div><div><br/></div><div><b>Design, setting and participants</b>:</div><div>Two arm trial randomizing care homes for older adults, with or without nursing and dementia care provision, and capacity for ≥20 residents in individual bedrooms.</div><div><br/></div><div><b>Interventions</b>:</div><div>Up to five HEPA filters for communal areas (clean air delivery rate (CADR) set at 160m3/hr) and up to 16 filters for bedrooms (CADR 60m3/hr). Both groups continued usual infection prevention and control measures. </div><div><br/></div><div><b>Main outcomes and measures</b>:</div><div>Primary outcome was respiratory infection rate per winter per ‘bedroom resident’ (exposed to bedroom and communal room filters). Secondary outcomes: infections with fever and/or delirium and/or acute physical deterioration; gastrointestinal infections; falls /near falls; infection-related primary care consultations; prescribed antibiotics; all-cause hospitalisations; and staff absenteeism. All outcomes also reported for residents exposed only to communal room filters.</div><div><br/></div><div><b>Results</b>:</div><div>Between September 2021 and May 2024, 91 care homes were randomized, 47 to receive communal room filters (with 569 bedroom residents) and 44 without communal room filters (and 589 residents without bedroom filters). There was no evidence of a difference in the number of respiratory infections per winter per bedroom resident (0.99 vs. 1.04, adjusted incident rate ratio (aIRR) 0.92, 95% confidence interval 0.64 to 1.33, p=0.67). Neither was there any evidence of a difference in the rates with fever with delirium and/or acute physical deterioration (aIRR 0.85, 0.57 to 1.28, p=0.44); gastrointestinal infections (aIRR 1.27, 0.52 to 3.09, p=0.59); falls/ near falls (aIRR 0.64, 0.35 to 1.17, p=0.15) primary care consultations (aIRR 1.21, 0.91 to 1.62, p=0.20); antibiotic prescribing (aIRR 1.14, 0.85 to 1.53, p=0.36); hospitalisations (aIRR 1.15, 0.75 to 1.76; p=0.53); or staff absenteeism (aIRR 0.80, 0.55 to 1.16; p=0.24). Results were similar for the residents exposed only to communal room HEPA filters.</div><div><br/></div><div><b>Conclusion and relevance:</b></div><div>There was no difference in resident respiratory (or other) infection rates in care homes with HEPA filters in communal areas and bedrooms. Care homes should continue existing recommended prevention measures to control respiratory and other infections.</div><div><br/></div><div><b>Trial registration</b>: ISRCTN: 63437172</div>