title: Impact of respiratory virus infections on persons with chronic underlying conditions.
abstract: BACKGROUND
  While hospitalization rates have declined overall, hospitalizations for acute lower respiratory tract infections have increased steadily since 1980. Development of new approaches for prevention of acute respiratory tract conditions requires studies of the etiologies of infections and quantification of the risk of hospitalization for vulnerable patients.
  
  
  OBJECTIVE
  To determine the frequency of specific virus infections associated with acute respiratory tract conditions leading to hospitalization of chronically ill patients.
  
  
  METHODS
  Analysis of viral etiology of patients hospitalized with acute respiratory tract conditions between July 1991 and June 1995.
  
  
  METHODS
  Four large clinics and related hospitals serving diverse populations representative of Harris County, Texas.
  
  
  METHODS
  A total of 1029 patients who were hospitalized for pneumonia, tracheobronchitis, bronchiolitis, croup, exacerbations of asthma or chronic obstructive pulmonary disease, and/or congestive heart failure.
  
  
  METHODS
  Virus infection, defined by culture, antigen detection, and significant rise in serum antibodies, by underlying condition; hospitalization rates by low- vs middle-income status.
  
  
  RESULTS
  Ninety-three percent of patients older than 5 years had a chronic underlying condition; a chronic pulmonary condition was most common. Patients with chronic pulmonary disease from low-income populations were hospitalized at a rate of 398.6 per 10000, almost 8 times higher than the rate for patients from middle-income groups (52.2 per 10000; P<.001). Of the 403 patients (44.4% of adults and 32.3% of children) who submitted convalescent serum specimens for antibody testing, respiratory tract virus infections were detected in 181 (44.9%). Influenza, parainfluenza, and respiratory syncytial virus (RSV) infections accounted for 75% of all virus infections.
  
  
  CONCLUSIONS
  Our study suggests that respiratory virus infections commonly trigger serious acute respiratory conditions that result in hospitalization of patients with chronic underlying conditions, highlighting the need for development of effective vaccines for these viruses, especially for parainfluenza and RSV.
authors.affiliation: Department of Microbiology and Immunology, Baylor College of Medicine, Houston, Tex 77030, USA. wglezen@bcm.tmc.edu
authors.forename: W P
authors.initials: WP
authors.lastname: Glezen
authors.forename: S B
authors.initials: SB
authors.lastname: Greenberg
authors.forename: R L
authors.initials: RL
authors.lastname: Atmar
authors.forename: P A
authors.initials: PA
authors.lastname: Piedra
authors.forename: R B
authors.initials: RB
authors.lastname: Couch
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D004198:Disease Susceptibility; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000453:epidemiology; D008875:Middle Aged; D018184:Paramyxoviridae Infections / Q000453:epidemiology; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000821:virology*; D012307:Risk Factors; D012959:Socioeconomic Factors