Respirators, face masks, and their risk reductions via multiple transmission routes for first responders within an ambulance.

Details

• Personal Author:
  Abney SE ; Jones RM ; King M-F ; Lugo Lerma V ; Noakes CJ ; Reynolds KA ; Sexton JD ; Weir MH ; Wilson AM
• Description:
  First responders may have high SARS-CoV-2 infection risks due to working with potentially infected patients in enclosed spaces. The study objective was to estimate infection risks per transport for first responders and quantify how first responder use of N95 respirators and patient use of cloth masks can reduce these risks. A model was developed for two Scenarios: an ambulance transport with a patient actively emitting a virus in small aerosols that could lead to airborne transmission (Scenario 1) and a subsequent transport with the same respirator or mask use conditions, an uninfected patient; and remaining airborne SARS-CoV-2 and contaminated surfaces due to aerosol deposition from the previous transport (Scenario 2). A compartmental Monte Carlo simulation model was used to estimate the dispersion and deposition of SARS-CoV-2 and subsequent infection risks for first responders, accounting for variability and uncertainty in input parameters (i.e., transport duration, transfer efficiencies, SARS-CoV-2 emission rates from infected patients, etc.). Infection risk distributions and changes in concentration on hands and surfaces over time were estimated across sub-Scenarios of first responder respirator use and patient cloth mask use. For Scenario 1, predicted mean infection risks were reduced by 69%, 48%, and 85% from a baseline risk (no respirators or face masks used) of 2.9 × 10-2 +/- 3.4 × 10-2 when simulated first responders wore respirators, the patient wore a cloth mask, and when first responders and the patient wore respirators or a cloth mask, respectively. For Scenario 2, infection risk reductions for these same Scenarios were 69%, 50%, and 85%, respectively (baseline risk of 7.2 × 10-3 +/- 1.0 × 10-2). While aerosol transmission routes contributed more to viral dose in Scenario 1, our simulations demonstrate the ability of face masks worn by patients to additionally reduce surface transmission by reducing viral deposition on surfaces. Based on these simulations, we recommend the patient wear a face mask and first responders wear respirators, when possible, and disinfection should prioritize high use equipment. [Description provided by NIOSH]
• Subjects:
  Aerosols Communicable Diseases Emergency Responders Occupational Health Personal Protective Equipment Respiratory Protective Devices Safety
• Keywords:
  Aerosols; SARS-CoV-2; COVID-19; Coronavirus; First Responders; Paramedics; Emergency Responders; Respiratory Protective Equipment; Respirators; Infectious Diseases; Face Masks; Author Keywords: Aerosol Transmission; COVID-19; EMS; Respirator
• ISSN:
  1545-9624
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Arizona ; California ; Ohio ; OSHA Region 5 ; OSHA Region 8 ; OSHA Region 9 ; Utah
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  345-360
• Volume:
  18
• Issue:
  7
• NIOSHTIC Number:
  nn:20064901
• Citation:
  J Occup Environ Hyg 2021 Jul; 18(7):345-360
• Contact Point Address:
  Amanda M. Wilson, Rocky Mountain Center for Occupational and Environmental Health, University of Utah, Salt Lake City, Utah
• Email:
  amwilson2@arizona.edu
• Federal Fiscal Year:
  2021
• Performing Organization:
  University of Utah
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• End Date:
  20280630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e4c23967c86910f4476c983a31a880052953af1e19c03d4e09fcffc57780fb2857736c3973e0b595bb69919f08dd1f1f402e0c08ad41d6dd2dd9b18ba2d86e57
• Download URL:
  https://stacks.cdc.gov/view/cdc/249270/cdc_249270_DS1.pdf
• File Type:
  [PDF - 2.95 MB ]