Relative Contributions of Four Exposure Pathways to Influenza Infection Risk

Details

• Personal Author:
  Jones RM ; Nicas M
• Description:
  The relative contribution of four influenza virus exposure pathways--(1) virus-contaminated hand contact with facial membranes, (2) inhalation of respirable cough particles, (3) inhalation of inspirable cough particles, and (4) spray of cough droplets onto facial membranes--must be quantified to determine the potential efficacy of nonpharmaceutical interventions of transmission. We used a mathematical model to estimate the relative contributions of the four pathways to infection risk in the context of a person attending a bed-ridden family member ill with influenza. Considering the uncertainties in the sparse human subject influenza dose-response data, we assumed alternative ratios of 3,200:1 and 1:1 for the infectivity of inhaled respirable virus to intranasally instilled virus. For the 3,200:1 ratio, pathways (1), (2), and (4) contribute substantially to influenza risk: at a virus saliva concentration of 106 mL-1, pathways (1), (2), (3), and (4) contribute, respectively, 31%, 17%, 0.52%, and 52% of the infection risk. With increasing virus concentrations, pathway (2) increases in importance, while pathway (4) decreases in importance. In contrast, for the 1:1 infectivity ratio, pathway (1) is the most important overall: at a virus saliva concentration of 106 mL-1, pathways (1), (2), (3), and (4) contribute, respectively, 93%, 0.037%, 3.3%, and 3.7% of the infection risk.With increasing virus concentrations, pathway (3) increases in importance, while pathway (4) decreases in importance. Given the sparse knowledge concerning influenza dose and infectivity via different exposure pathways, nonpharmaceutical interventions for influenza should simultaneously address potential exposure via hand contact to the face, inhalation, and droplet spray. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Air Pollution, Indoor Bacteria Bacterial Infections Dust Environmental Exposure Environmental Monitoring Environmental Pollution Hazardous Substances Immune System Inhalation Exposure Laboratories Occupational Health Particulate Matter Respiratory System Risk Assessment Risk Factors Safety

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• Keywords:
  Aerosol-particles Air-contamination Airborne-particles Author Keywords: Influenza Bacterial-dusts Bacterial-infections Biological-effects Biological-function Cell-biology Environmental-contamination Environmental-exposure Exposure-assessment Exposure-levels Exposure-methods Health-hazards Health-standards Immune-reaction Immune-system Inhalants Inhalation-studies Laboratory-testing Mathematical-models Microbial Risk Assessment Pollutants Quantitative-analysis Risk-analysis Risk-factors Statistical-analysis Surface-properties Transmission Pathway

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• ISSN:
  0272-4332
• Document Type:
  Text
• Funding:
  Grant ; Contract
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  29
• Issue:
  9
• NIOSHTIC Number:
  nn:20037357
• Citation:
  Risk Anal 2009 Sep; 29(9):1292-1303
• Contact Point Address:
  Mark Nicas, Room 50, University Hall, School of Public Health,University of California, Berkeley, Berkeley, CA 94720-7360
• Federal Fiscal Year:
  2009
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Risk Analysis
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c32ebc36b6b99791eb69719d97ce65b846111df0110af8c73407b094a192cca2d2dcb2e6769309de32d9ad6ba8d9ce412aaf8211fd9c363a2a02437440c7af84
• Download URL:
  https://stacks.cdc.gov/view/cdc/188458/cdc_188458_DS1.pdf
• File Type:
  [PDF - 214.67 KB ]