Air filtration systems may be more the norm in long-term care facilities post-pandemic, but a new study says they can’t stop people from getting viral infections.
A team from the University of East Anglia reviewed multiple studies evaluating technologies such as air filter devices, germicidal lights and ionizers.
The new study clashes with previous understanding about how effective the above sanitation tools can be and clouds the picture for how senior living and care operators may keep residences free of COVID-19 or flu.
“Air treatment technologies can be expensive. So it’s reasonable to weigh up the benefits against costs, and to understand the current capabilities of such technologies,” study co-author Paul Hunter, MD, said in a statement.
Such costly technologies on the market include disinfecting robots that move around and deploy ultraviolet lights; those robo-cleaners even now have an FDA-classification.
The team assessed details from 32 studies on microbial infections or symptoms in people exposed or not to air treatment technologies. The studies all were performed in real-life settings such as nursing homes and schools.
“In short, we found no strong evidence that air treatment technologies are likely to protect people in real world settings,” Julii Brainard, PhD, a report author also from UEA’s Norwich Medical School.
The study team appeared to hedge their conclusion in part by noting that a handful of studies on air treatment solutions launched during the COVID-19 pandemic haven’t been published, but would be “welcome to the evidence base.”
Some recent studies that have been published, however, have found that air purification interventions do reduce COVID in nursing homes.
The East Anglia study authors seem to indirectly acknowledge this, writing that “There is a lot of existing evidence that environmental and surface contamination can be reduced by several air treatment strategies, especially germicidal lights and high efficiency particulate air filtration (HEPA).”
In addition, the study team cited “weak evidence” that the air treatment methods lowered the risk for infection but that these studies were “biased or imbalanced.”
They conclude that their meta-analysis overall shows that the “combined evidence” of these various technologies suggests they “don’t stop or reduce illness.”
Equally concerning, whether or not UV-light filters kill germs, some systems may produce new, unrelated toxins in the air, such as ozone, one recent study found.
The East Anglia study was published Nov. 16 in Preventive Medicine.
