High Humidity Leads to Loss of Infectious Influenza Virus from Simulated Coughs

Authors

John D. Noti, National Institute for Occupational Safety and Health (NIOSH)
Francoise M. Blachere, National Institute for Occupational Safety and Health (NIOSH)
Cynthia M. McMillen, West Virginia University
William G. Lindsley, National Institute for Occupational Safety and Health (NIOSH)
Michael L. Kashon, National Institute for Occupational Safety and Health (NIOSH)
Denzil R. Slaughter, National Institute for Occupational Safety and Health (NIOSH)
Donald H. Beezhold, National Institute for Occupational Safety and Health (NIOSH)

Author ORCID Identifier

https://orcid.org/0000-0002-2927-9530

https://orcid.org/0000-0003-1022-9741

https://orcid.org/0000-0001-9211-7908

https://orcid.org/0000-0003-0720-5829

N/A

N/A

https://orcid.org/0000-0001-5543-5747

Document Type

Article

Publication Date

2013

College/Unit

School of Medicine

Department/Program/Center

Microbiology, Immunology, and Cell Biology

Abstract

Background

The role of relative humidity in the aerosol transmission of influenza was examined in a simulated examination room containing coughing and breathing manikins.

Methods

Nebulized influenza was coughed into the examination room and Bioaerosol samplers collected size-fractionated aerosols (<1 µM, 1–4 µM, and >4 µM aerodynamic diameters) adjacent to the breathing manikin’s mouth and also at other locations within the room. At constant temperature, the RH was varied from 7–73% and infectivity was assessed by the viral plaque assay.

Results

Total virus collected for 60 minutes retained 70.6–77.3% infectivity at relative humidity ≤23% but only 14.6–22.2% at relative humidity ≥43%. Analysis of the individual aerosol fractions showed a similar loss in infectivity among the fractions. Time interval analysis showed that most of the loss in infectivity within each aerosol fraction occurred 0–15 minutes after coughing. Thereafter, losses in infectivity continued up to 5 hours after coughing, however, the rate of decline at 45% relative humidity was not statistically different than that at 20% regardless of the aerosol fraction analyzed.

Conclusion

At low relative humidity, influenza retains maximal infectivity and inactivation of the virus at higher relative humidity occurs rapidly after coughing. Although virus carried on aerosol particles <4 µM have the potential for remaining suspended in air currents longer and traveling further distances than those on larger particles, their rapid inactivation at high humidity tempers this concern. Maintaining indoor relative humidity >40% will significantly reduce the infectivity of aerosolized virus.

Digital Commons Citation

Noti, John D.; Blachere, Francoise M.; McMillen, Cynthia M.; Lindsley, William G.; Kashon, Michael L.; Slaughter, Denzil R.; and Beezhold, Donald H., "High Humidity Leads to Loss of Infectious Influenza Virus from Simulated Coughs" (2013). Faculty & Staff Scholarship. 2641.
https://researchrepository.wvu.edu/faculty_publications/2641

Source Citation

Noti, J. D., Blachere, F. M., McMillen, C. M., Lindsley, W. G., Kashon, M. L., Slaughter, D. R., & Beezhold, D. H. (2013). High Humidity Leads to Loss of Infectious Influenza Virus from Simulated Coughs. PLoS ONE, 8(2), e57485. https://doi.org/10.1371/journal.pone.0057485

Comments

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.