Technology designed to make social interactions safer indoors may not be successful in real-world settings, a new study highlights. The research team looked at various technologies including air filtration systems, germicidal lamps and ionizers. New research from the University of East Anglia shows that air filtration systems are not effective in reducing the risk of viral infection, challenging the expected benefits of these expensive systems in public health settings.

They looked at all the available evidence but found little to support the hope that these technologies could free the air from respiratory or gastrointestinal infections.

Professor Paul Hunter, from UEA's Norwich Medical School, said: "The role of an air purifier is to filter pollutants from the air. During the Covid-19 pandemic, many large companies and governments, including the NHS, the UK military, New York City and regional governments in Germany, were looking at installing this technology to reduce airborne virus particles in buildings and small spaces. However, air treatment technology can be expensive. Therefore, it is reasonable to weigh the benefits against the costs and understand the existing capabilities of such technology."

Evidence Analysis and Research Results

The team looked at the evidence on whether air purification technology could protect people from airborne respiratory or gastrointestinal infections.

They analyzed evidence from 32 studies on microbial infections or symptoms in people exposed or not exposed to air treatment technologies, all conducted in real-life settings such as schools or care homes. To date, not a single air treatment study begun in the Covid era has been published.

Lead researcher Dr Julii Brainard, also from UEA Norwich Medical School, said: "The technologies we considered included filtration, germicidal lamps, ionizers and anything else that would safely remove the virus or inactivate it in breathable air. In summary, we found no strong evidence that Air treatment technologies have the potential to protect people's health in real-world settings. There is substantial existing evidence that environmental and surface contamination can be reduced through several air treatment strategies, particularly germicidal lamps and high-efficiency particulate air filtration (HEPA), but the combined evidence suggests that these technologies do not prevent or reduce the occurrence of disease."

"There is some weak evidence that air treatment methods reduce the likelihood of infection, but this evidence appears to be biased and balanced. We strongly suspect that there are related studies with very small or no effect, but these studies have never been published. Our findings are disappointing, but it is critical to give public health decision-makers a full picture. Hopefully, those studies conducted during the COVID-19 pandemic will be published soon so that we can make more informed judgments about the value of air treatment during the pandemic."

Reference: The effect of filtering or purifying air in reducing or preventing respiratory infections: Julie Brainard, Natalia R. Jones, Isabel Catalina Swindells, Elizabeth J. Archer, Anastasia Kolyva, Charlotte Letley, Katharine Pond, Iain R. Lake and Paul R. Hunter, November 20, 2023, "Preventive Medicine".

DOI:10.1016/j.ypmed.2023.107774

Compiled source: ScitechDaily