Air cleaners and respiratory infections in schools. A modeling study using epidemiological, environmental, and molecular data

AbstractBackgroundUsing a multiple-measurement approach, we examined the real-world effectiveness of portable HEPA-air filtration devices (air cleaners) in a school setting.MethodsWe collected environmental (CO2, particle concentrations), epidemiological (absences related to respiratory infections), audio (coughing), and molecular data (bioaerosol and saliva samples) over seven weeks during winter 2022/2023 in two Swiss secondary school classes. Using a cross-over study design, we compared particle concentrations, coughing, and the risk of infection with vs without air cleaners.ResultsAll 38 students (age 13−15 years) participated. With air cleaners, mean particle con-centration decreased by 77% (95% credible interval 63%−86%). There were no differences in CO2levels. Absences related to respiratory infections were 22 without vs 13 with air cleaners. Bayesian modeling suggested a reduced risk of infection, with a posterior probability of 91% and a relative risk of 0.73 (95% credible interval 0.44−1.18). Coughing also tended to be less frequent (posterior probability 93%). Molecular analysis detected mainly non-SARS-CoV-2 viruses in saliva (50/448 positive), but not in bioaerosols (2/105 positive) or HEPA-filters (4/160). The detection rate was similar with vs without air cleaners. Spatiotemporal analysis of positive saliva samples identified several likely transmissions.ConclusionsAir cleaners improved air quality, showed a potential benefit in reducing respiratory infections, and were associated with less coughing. Airborne detection of non-SARS-CoV-2 viruses was rare, suggesting that these viruses may be more difficult to detect in the air. Future studies should examine the importance of close contact and long-range transmission, and the cost-effectiveness of using air cleaners.

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Subject (DDC)

610 - Medizin und Gesundheit

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ISSN

2328-8957

Language

English

Created during FHNW affiliation

Yes

Strategic action fields FHNW

Publication status

Published

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Peer review of the complete publication

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Closed

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Citation

Banholzer, N., Jent, P., Bittel, P., Zürcher, K., Furrer, L., Bertschinger, S., Weingartner, E., Ramette, A., Egger, M., Hascher, T., & Fenner, L. (2023). Air cleaners and respiratory infections in schools. A modeling study using epidemiological, environmental, and molecular data. Open Forum Infectious Diseases. https://doi.org/10.1101/2023.12.29.23300635

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