Distribution of airborne influenza virus and respiratory syncytial virus in an urgent care medical clinic.
BACKGROUND
Considerable controversy exists with regard to whether influenza virus and respiratory syncytial virus (RSV) are spread by the inhalation of infectious airborne particles and about the importance of this route, compared with droplet or contact transmission.


METHODS
Airborne particles were collected in an urgent care clinic with use of stationary and personal aerosol samplers. The amounts of airborne influenza A, influenza B, and RSV RNA were determined using real-time quantitative polymerase chain reaction. Health care workers and patients participating in the study were tested for influenza.


RESULTS
Seventeen percent of the stationary samplers contained influenza A RNA, 1% contained influenza B RNA, and 32% contained RSV RNA. Nineteen percent of the personal samplers contained influenza A RNA, none contained influenza B RNA, and 38% contained RSV RNA. The number of samplers containing influenza RNA correlated well with the number and location of patients with influenza (r= 0.77). Forty-two percent of the influenza A RNA was in particles < or = 4.1 microm in aerodynamic diameter, and 9% of the RSV RNA was in particles < or = 4.1 microm.


CONCLUSIONS
Airborne particles containing influenza and RSV RNA were detected throughout a health care facility. The particles were small enough to remain airborne for an extended time and to be inhaled deeply into the respiratory tract. These results support the possibility that influenza and RSV can be transmitted by the airborne route and suggest that further investigation of the potential of these particles to transmit infection is warranted.
Lindsley
William G
WG
Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia 26505-2845, USA. wlindsley@cdc.gov
Blachere
Francoise M
FM
Davis
Kristina A
KA
Pearce
Terri A
TA
Fisher
Melanie A
MA
Khakoo
Rashida
R
Davis
Stephen M
SM
Rogers
Mark E
ME
Thewlis
Robert E
RE
Posada
Jose A
JA
Redrow
John B
JB
Celik
Ismail B
IB
Chen
Bean T
BT
Beezhold
Donald H
DH
D000328:Adult; D000391:Air Microbiology; D000553:Ambulatory Care; D002648:Child; D002675:Child, Preschool; D006282:Health Personnel; D006761:Hospitals; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification*; D009981:Influenza B virus / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis; D016133:Polymerase Chain Reaction / Q000379:methods; D012367:RNA, Viral / Q000302:isolation & purification; D018113:Respiratory Syncytial Virus, Human / Q000302:isolation & purification*; D055815:Young Adult
D012367:RNA, Viral