A scoping review identified and described primary studies evaluating the effects of physical changes to workplaces or equipment designed to prevent or control infection, also known as engineering infection control interventions. The review found substantial heterogeneity in available evidence and identified gaps in evidence including measurement of harms or efficacy outcomes relevant to human-to-human infection transmission. The review is published in Annals of Internal Medicine.
Researchers from the University of Colorado Anschutz Medical Campus and National Institute for Occupational Safety and Health (NIOSH)/Centers for Disease Control and Prevention (CDC) reviewed findings from 672 studies published between 1929 and 2024 that evaluate the effects of engineering infection control interventions designed to reduce the spread of respiratory infections transmitted through indoor air.
They classified engineering infection control components into two broad categories: strategies that dilute pathogens or move air (ventilation) and those that directly capture or inactivate pathogens (filters, germicidal ultraviolet light). They categorized studies into three types: human (those evaluating the effect of interventions on infection transmission in humans); sentinel animal (those evaluating the effect of human pathogen transmission in sentinel animals); and 3) environmental (those performed in chamber or real-world settings and examining intervention effects on air or surface microbial loads, particulate matter counts, and tracer gas concentrations).
They developed a rating system to assess the value of study outcome measures based on their relevance to infection transmission in humans. The researchers found that 90% of studies were classified as environmental studies and most often measured surrogate outcomes, such as microbes in air samples, rather than direct human infectious outcomes. Studies measuring outcomes in humans were largely observational and conducted in healthcare settings.
Most studies (61%) examined a single engineering control intervention, an the most frequently studied interventions involved pathogen inactivation, pathogen removal via HEPA filters, or air exchange or dilution. Overall, few studies directly examined the effects of engineering control interventions on human-to-human indoor transmission of respiratory pathogens, and even fewer reported on potential harms, such as toxic byproducts.
Source: American College of Physicians (ACP)