title: Laboratory surveillance of influenza-like illness in seven teaching hospitals, South Korea: 2011-2012 season.
abstract: BACKGROUND
  A well-constructed and properly operating influenza surveillance scheme is essential for public health. This study was conducted to evaluate the distribution of respiratory viruses in patients with influenza-like illness (ILI) through the first teaching hospital-based surveillance scheme for ILI in South Korea.
  
  
  METHODS
  Respiratory specimens were obtained from adult patients (≥18 years) who visited the emergency department (ED) with ILI from week 40, 2011 to week 22, 2012. Multiplex PCR was performed to detect respiratory viruses: influenza virus, adenovirus, coronavirus, respiratory syncytial virus, rhinovirus, human metapneumovirus, parainfluenza virus, bocavirus, and enterovirus.
  
  
  RESULTS
  Among 1,983 patients who visited the ED with ILI, 811 (40.9%) were male. The median age of patients was 43 years. Influenza vaccination rate was 21.7% (430/1,983) during the 2011-2012 season. At least one comorbidity was found in 18% of patients. The positive rate of respiratory viruses was 52.1% (1,033/1,983) and the total number of detected viruses was 1,100. Influenza A virus was the dominant agent (677, 61.5%) in all age groups. The prevalence of human metapneumovirus was higher in patients more than 50 years old, while adenovirus was detected only in younger adults. In 58 (5.6%) cases, two or more respiratory viruses were detected. The co-incidence case was identified more frequently in patients with hematologic malignancy or organ transplantation recipients, however it was not related to clinical outcomes.
  
  
  CONCLUSIONS
  This study is valuable as the first extensive laboratory surveillance of the epidemiology of respiratory viruses in ILI patients through a teaching hospital-based influenza surveillance system in South Korea.
authors.affiliation: Department of Microbiology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Noh
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.forename: Jacob
authors.initials: J
authors.lastname: Lee
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Lee
authors.forename: Seong-Heon
authors.initials: SH
authors.lastname: Wie
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Jeong
authors.forename: Young Keun
authors.initials: YK
authors.lastname: Kim
authors.forename: Sung Hyuk
authors.initials: SH
authors.lastname: Choi
authors.forename: Seung Baik
authors.initials: SB
authors.lastname: Han
authors.forename: Byung-Hak
authors.initials: BH
authors.lastname: So
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D011159:Population Surveillance; D056910:Republic of Korea / Q000453:epidemiology; D014777:Virus Diseases / Q000453:epidemiology*