Article Impact Level: HIGH Data Quality: STRONG Summary of Annals of Internal Medicine, ANNALS-25-00577. https://doi.org/10.7326/ANNALS-25-00577 Dr. Amiran Baduashvili et al.
Points
- A systematic review analyzed 672 studies from 1929 to 2024 to evaluate the effectiveness of engineering controls in reducing the transmission of indoor respiratory infections.
- Pathogen inactivation was the most frequently studied intervention, while the vast majority of studies relied on environmental sampling rather than including human participants.
- Researchers most commonly measured surrogate outcomes, such as nonpathogenic organisms or particulates, rather than clinically relevant endpoints, including direct human infection transmission.
- The review identified a critical lack of data on outcomes highly relevant to human health, including infection rates and potential harms from the interventions.
- Substantial heterogeneity exists in the available evidence, underscoring the need for refined classifications and methodologies to enhance future research in this critical area.
Summary
A systematic review was conducted to identify and describe primary studies evaluating engineering infection control interventions designed to reduce the indoor transmission of respiratory infections. Researchers conducted a comprehensive search of seven databases, including MEDLINE and Embase, from their inception to December 12, 2023, selecting only English-language primary research. Data on publication, population, intervention, and outcomes were abstracted by one reviewer and verified by a second, with the protocol registered on the Open Science Framework.
The review identified 672 studies published between 1929 and 2024. The majority of these (n = 606) were based on environmental samples only, with a small fraction including human participants (n = 57) or sentinel animal subjects (n = 9). Pathogen inactivation was the most common intervention studied (n = 405), followed by pathogen removal (n = 200) and air exchange or dilution (n = 143). The most frequently measured outcome, present in approximately half of the studies (n = 332), was the quantity of viable nonpathogenic organisms from air samples. Fewer studies measured nonbiological particulates (n = 197) or viable pathogenic organisms (n = 149).
The authors concluded that the evidence base is substantially heterogeneous and identified critical gaps in the literature. Notably, there is a scarcity of research measuring clinically relevant efficacy outcomes, such as rates of human infection, and infrequent assessments of potential harms, including toxic byproducts. The study was limited by the exclusion of non–English-language publications and gray literature. The findings suggest that refining the classification of interventions and outcomes is necessary to strengthen future evaluations and improve evidence synthesis.
Link to the article: https://www.acpjournals.org/doi/10.7326/ANNALS-25-00577
References Baduashvili, A., Radonovich, L., Leslie, L., Pease, S., Brickson, C., Chockalingam, L., Banacos, N., Fitzgerald, B., Wagner, J., Bahnfleth, W. P., Cox-Ganser, J., Mead, K. R., Olsiewski, P., Gregory, C. O., Stone, E., Taliano, J., Weissman, D. N., & Bero, L. (2025). Engineering infection controls to reduce indoor transmission of respiratory infections: A scoping review. Annals of Internal Medicine, ANNALS-25-00577. https://doi.org/10.7326/ANNALS-25-00577
