title: Quantification of Influenza Virus RNA in Aerosols in Patient Rooms.
abstract: BACKGROUND
  The potential for human influenza viruses to spread through fine particle aerosols remains controversial. The objective of our study was to determine whether influenza viruses could be detected in fine particles in hospital rooms.
  
  
  RESULTS
  We sampled the air in 2-bed patient isolation rooms for four hours, placing cyclone samplers at heights of 1.5m and 1.0m. We collected ten air samples each in the presence of at least one patient with confirmed influenza A virus infection, and tested the samples by reverse transcription polymerase chain reaction. We recovered influenza A virus RNA from 5/10 collections (50%); 4/5 were from particles>4 μm, 1/5 from 1-4 μm, and none in particles<1 μm.
  
  
  CONCLUSIONS
  Detection of influenza virus RNA in aerosols at low concentrations in patient rooms suggests that healthcare workers and visitors might have frequent exposure to airborne influenza virus in proximity to infected patients. A limitation of our study was the small sample size. Further studies should be done to quantify the concentration of viable influenza virus in healthcare settings, and factors affecting the detection of influenza viruses in fine particles in the air.
authors: WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Nancy H L
authors: NH
authors: Leung
authors: Centre of Influenza Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Jie
authors: J
authors: Zhou
authors: Centre of Influenza Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Daniel K W
authors: DK
authors: Chu
authors: Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Han
authors: H
authors: Yu
authors: Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States of America.
authors: William G
authors: WG
authors: Lindsley
authors: Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States of America.
authors: Donald H
authors: DH
authors: Beezhold
authors: WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.|Centre of Influenza Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Hui-Ling
authors: HL
authors: Yen
authors: Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Yuguo
authors: Y
authors: Li
authors: WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Wing-Hong
authors: WH
authors: Seto
authors: WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.|Centre of Influenza Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Joseph S M
authors: JS
authors: Peiris
authors: WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors: Benjamin J
authors: BJ
authors: Cowling
mesh_terms: D000328:Adult; D000336:Aerosols; D016902:Air Pollution, Indoor / Q000032:analysis*; D005260:Female; D006761:Hospitals; D006801:Humans; D009980:Influenza A virus; D008297:Male; D012367:RNA, Viral / Q000032:analysis*
chemical_list: D000336:Aerosols; D012367:RNA, Viral