title: Viable influenza A virus in airborne particles from human coughs.
abstract: Patients with influenza release aerosol particles containing the virus into their environment. However, the importance of airborne transmission in the spread of influenza is unclear, in part because of a lack of information about the infectivity of the airborne virus. The purpose of this study was to determine the amount of viable influenza A virus that was expelled by patients in aerosol particles while coughing. Sixty-four symptomatic adult volunteer outpatients were asked to cough 6 times into a cough aerosol collection system. Seventeen of these participants tested positive for influenza A virus by viral plaque assay (VPA) with confirmation by viral replication assay (VRA). Viable influenza A virus was detected in the cough aerosol particles from 7 of these 17 test subjects (41%). Viable influenza A virus was found in the smallest particle size fraction (0.3 μm to 8 μm), with a mean of 142 plaque-forming units (SD 215) expelled during the 6 coughs in particles of this size. These results suggest that a significant proportion of patients with influenza A release small airborne particles containing viable virus into the environment. Although the amounts of influenza A detected in cough aerosol particles during our experiments were relatively low, larger quantities could be expelled by influenza patients during a pandemic when illnesses would be more severe. Our findings support the idea that airborne infectious particles could play an important role in the spread of influenza.
authors.affiliation: a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , West Virginia.
authors.forename: William G
authors.initials: WG
authors.lastname: Lindsley
authors.forename: John D
authors.initials: JD
authors.lastname: Noti
authors.forename: Francoise M
authors.initials: FM
authors.lastname: Blachere
authors.forename: Robert E
authors.initials: RE
authors.lastname: Thewlis
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Martin
authors.forename: Sreekumar
authors.initials: S
authors.lastname: Othumpangat
authors.forename: Bahar
authors.initials: B
authors.lastname: Noorbakhsh
authors.forename: William T
authors.initials: WT
authors.lastname: Goldsmith
authors.forename: Abhishek
authors.initials: A
authors.lastname: Vishnu
authors.forename: Jan E
authors.initials: JE
authors.lastname: Palmer
authors.forename: Karen E
authors.initials: KE
authors.lastname: Clark
authors.forename: Donald H
authors.initials: DH
authors.lastname: Beezhold
mesh_terms: D000293:Adolescent; D000328:Adult; D000336:Aerosols / Q000032:analysis*; D000391:Air Microbiology; D003371:Cough / Q000821:virology*; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification*; D007251:Influenza, Human / Q000635:transmission*; D008297:Male; D010316:Particle Size; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D010948:Viral Plaque Assay; D014779:Virus Replication
chemical_list: D000336:Aerosols; D012367:RNA, Viral
keywords: aerosols; air microbiology; airborne transmission; cough; infectious disease transmission; influenza