The largest randomized trial yet conducted on portable air purifiers in residential care found no benefit, and the argument that has broken out over the result is more useful to readers than the result itself.
British researchers randomized 95 care homes in England, roughly half receiving portable HEPA filtration units for communal areas and residents' bedrooms and half continuing with usual care, and tracked more than 1,100 older residents across three winters. Writing in JAMA Internal Medicine, the authors reported that they "found no evidence that HEPA filters reduced resident winter respiratory infection episodes, other infections, antibiotic use, or staff absenteeism."
