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