The effect of air filtration devices on transmission of infectious diseases in an educational setting: A literature review
Boer, Li Xiang den
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ABSTRACT Background: Respiratory infectious diseases are an important cause for morbidity and mortality. The transmission of infectious diseases in schools influences the incidence of these diseases in the rest of the population. It has been hypothesized that air filtration devices might be able to reduce the transmission of infectious diseases. In healthcare settings air filtration devices seem to be effective in reducing the aerosol particle concentration and infection rate. However, there is no overview of the available evidence of these devices in a school setting. Therefore, the aim of this study was to summarize the existing evidence on the effect of air filtration devices in educational settings. Methods: PubMed/MEDLINE and EMBASE were searched in May 2023. Intervention studies that were conducted in a school setting were eligible. Modeling and simulation studies, and observational studies were excluded. Risk of bias was assessed using a modified version of the ROBINS-I tool. The details of the classroom, device and quantitative measurement of the effect were extracted. Results: Two studies met the inclusion criteria. The two studies were conducted in Germany after 2020. One was conducted at a primary school, the other at a secondary school. Both studies were non-randomized trials, that compared a classroom with and without air purifier. Neither of the included studies measured outcomes that were directly related to infectious disease transmission. They measured the aerosol particle concentration, particle size distribution, CO2 levels, and relative humidity. Overall, they were both found to have moderate risk of bias. The air purifiers were found to reduce the aerosol particle concentration by 88.9% and 95%, compared to 11.8%, while not using air purifiers reduced it by 11.8% and 30% respectively. Conclusion: None of the included studies measured outcomes related to infectious disease transmission. However, both studies concluded that using an air purifier with HEPA filter significantly reduced the aerosol particle concentration. Future research is necessary that uses outcome measures of infectious disease transmission, such as virus concentration or incidence of infection.