Linking SARS-CoV-2 Aerosol Viability and Environmental Factors in Healthcare Settings

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PROJECT SUMMARY/ABSTRACT Aerosolization of viruses from patients with respiratory infections, such as COVID-19 and influenza, is a major concern in healthcare because these viruses can put healthcare personnel (HCP) and patients at risk of infection. The rationale for this study is that while epidemiology studies have identified some healthcare activities as posing a high risk to HCP and these activities are thought to generate aerosols, there exists very limited information about the concentration and size distribution of infectious virus in the aerosol. As a result, it remains difficult to identify aerosol-generating healthcare activities and to distinguish those that pose a high risk to HCP and patients. The long-term goal of this research is to prevent the transmission of viral diseases through respiratory aerosol. Three aims are proposed. Aim 1 is to develop and evaluate a size-selective method to assess viable virus in aerosol. Commercially available size-selective inlets meeting health-based sampling conventions will be evaluated for use with an innovative instrument, the Viable Virus Aerosol Sampler (VIVAS, Aerosol Devices, Inc.), with reference aerosols and bacteriophage MS2. Aim 2 is to characterize the concentration and size distribution of viable virus aerosol generated from healthcare activities.One or more inlet from Aim 1 will be deployed alongside conventional aerosol sampling equipment to measuresize-selected viable virus, size-selected virus genetic material, and aerosol number and size distribution in rooms with influenza or COVID-19 patients. Six healthcare activities will be studied, each with 6-9 observationsfor COVID- 19 patients and 6-9 observations for influenza patients. These activities will be selected based on preliminary aerosol characterization of 15 activities. The primary hypothesis of Aim 2 is that the variance in respiratory aerosol is greater among healthcare activities than within healthcare activities, and does not vary between viruses, which implies that some activities generate more or different aerosol than others. The secondary hypothesis of Aim 2 is that therethe ratio of virus gene copies to viable virus in respiratory aerosol does not vary within or among healthcare activities, which, if true, means that the viable virus concentration can be reliably inferred from PCR results. Aim 3 is to link aerosol properties to patient, procedure, and environmental characteristics. The primary hypothesis of Aim 3 is that the variance in respiratory aerosol characteristics explained by environmental, patient, and healthcare activity characteristics is small relative to variation within and among healthcare activities, which reflects that limited variation in environmental and patient characteristics are expected owing to the performance of this research in a healthcare facility and among hospitalized patients. The knowledge generated through this research will greatly enhance our understanding ofthe risks posed by viruses in respiratory aerosol. Infection preventionists will be able to use this knowledge to educate HCP, and to select control strategies that permit HCP to perform their jobs safely and efficiently. The outcome of this research will be evidence-based infection prevention practices for aerosol-generating activities.