Supplementary air filtration systems in health service settings

Context

COVID-19 can be spread through the air and linger in a space for as much as three hours.  

To reduce this spread, particularly within healthcare settings (such as hospitals and dental clinics), research has been carried out by the Wales COVID-19 Evidence Centre to understand the benefits of ‘supplementary air filtration’ systems to clean the air of these infectious COVID-19 particles.

Aim

The aim of this review is to understand how effective these filtration devices can be in removing COVID-19 from the air in a room.  This is hoped to improve the outcomes for patients in hospital and other healthcare locations.

Methods

A range of existing studies on the use of air filtration systems across the world were reviewed. These included studies of the benefits of air filtration systems in dental clinics, as well as some hospitals in the UK and Sweden. Some of the studies have a high risk of bias.

Findings

Evidence to support the use of air filtration systems is currently limited but does appear to show that they can be beneficial in reducing COVID-19 air particles in a room, and related transmission rates within healthcare settings. As some of the studies where of a lower quality it is still important to carry out further research to understand the true benefits of air filtration systems. Of the devices reviewed, the HEPA (High Efficiency Particulate Air) filter and UV light appear to provide the best outcomes.

Conclusion

This is a complex issue and more research is required for clarity. Using two different systems together seems to provide better results than using just one alone. Combined with a good level of ventilation, these systems could be very helpful. The placement of systems can have a big impact on how well they work to clean the air.

Policy Implications

The issue of cost-effectiveness needs to be considered when introducing these portable devices or altering existing systems.

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Summary author: Robert Hall