PMID:
PLoS One. 2013 ;8(2):e57485. Epub 2013 Feb 27. PMID: 23460865
Abstract Title:
High humidity leads to loss of infectious influenza virus from simulated coughs.
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 (4µM 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 particles40% will significantly reduce the infectivity of aerosolized virus.
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