Air filtration devices: An easy solution to reduce COVID-19 in hospitals

A simple solution that involves use of air filtration devices may help reduce the risk of hospital-acquired SARS-CoV-2 infections.

A simple solution that involves use of air filtration devices may help reduce the risk of hospital-acquired SARS-CoV-2 infections, according to Andrew Conway-Morris,BSc (Hons), MBChB (Hons), PhD, from The John Farman ICU, Cambridge University Hospitals NHS Foundation Trust, and University Division of Anaesthesia, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK.

“The use of such systems may provide additional safety for those that are of high exposure risk to respiratory pathogens such as SARS-CoV-2,” the investigators commented.

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In their crossover study,1the authors evaluated portable air filtration and sterilization devices in a repurposed so-called “surge” COVID ward and surge intensive care unit (ICU) in Addenbrooke’s Hospital, Cambridge, UK, during January and February 2021.

They used National Institute for Occupational Safety and Health cyclonic aerosol samplers and polymerase chain reaction assays to detect airborne SARS-CoV-2 and other microbial bioaerosols with and without air/ultraviolet (UV) filtration.

At the time of this study, the alpha variant predominated.

In the surge ward (4 beds), clinicians treated patients who needed simple oxygen therapy or no respiratory support, and in the ICU (5 beds and 6 beds during the second week) the patients needed invasive and non-invasive respiratory support.

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During the study, the units were fully occupied.

The investigators installedan AC1500 HEPA14/UV steriliser (Filtrex, Harlow, UK) in the ward and a Medi 10 HEPA13/UV steriliser (Max Vac, Zurich, Switzerland) in the ICU.

The researchers reported detecting airborne SARS-CoV-2 in the ward on all 5 days before the air/UV filtration was activated but not during the 5 days when the air/UV filter was activated.

After the filtration system was deactivated, SARS-CoV-2 was detected again during 4 of 5 days of sampling. In the ICU, airborne pathogens were detected infrequently.

“Filtration significantly reduced the burden of other microbial bioaerosols in both the ward (48 pathogens detected before filtration, two after, p=0.05) and the ICU (45 pathogens detected before filtration, five after, p=0.05),” they commented.

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The data showed that viral particles were present in areas that were not considered to be aerosol risk areas.

“The use of such systems may provide additional safety for those that are of high exposure risk to respiratory pathogens such as SARS-CoV-2,” the authors concluded.

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Reference
1. Conway-Morris A, Sharrocks K, Bousfield R, et al. The removal of airborne SARS-CoV-2 and other microbial bioaerosols by air filtration on COVID-19 surge units. medRxiv 2021; posted September 22, 2021; https://www.medrxiv.org/content/10.1101/2021.09.16.21263684v1