title: Characteristics of outpatients with pandemic H1N1/09 influenza in a tertiary care university hospital in Korea.
abstract: The pandemic H1N1/09 emerged rapidly in Korea. Here, we describe the clinical characteristics of outpatients in Seoul, Korea who were infected in the 2009 H1N1 pandemic. We reviewed the cases of outpatients with pandemic H1N1/09 who visited a tertiary care teaching hospital between September 1 and December 31, 2009. Infection with pandemic H1N1/09 was confirmed by molecular tests. Of a total of 7,182 tests, 3,020 (42.0%) were positive. Compared with 473 cases of influenza- like illness (ILI), the 586 confirmed cases of pandemic H1N1/09 differed in age [odds ratio (OR) 0.975] and fulfilling at least one of the following factors: age < 5 or ≥ 65 years, history of contact with other pandemic H1N1/09-infected individuals (OR 0.611), fever ≥ 37.8°C (OR 3.567), cough (OR 2.290), and myalgia (OR 1.559). The sensitivity of the best criteria, "fever (≥ 37.8°C) plus cough" (41.03%) in this study was lower than that of the Korea Centers for Disease Control and Prevention (KCDC) criteria (47.95%), whereas the positive likelihood ratio (3.55) and positive predictive value (81.6) of this criteria was higher than those of the KCDC criteria (2.98 and 78.7, respectively). The clinical characteristics of pandemic H1N1/09 are, in many regards, indistinguishable from those of ILI. Moreover, the accuracy and predictability of criteria which include only symptoms or signs were not sufficient to diagnose pandemic H1N1/09 infection. Therefore, use of a combination of symptoms with confirmatory laboratory testing is necessary for accurate diagnosis of pandemic H1N1/09.
authors.affiliation: Department of Laboratory Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Kyung Sun
authors.initials: KS
authors.lastname: Park
authors.forename: Tae Sung
authors.initials: TS
authors.lastname: Park
authors.forename: Jin Tae
authors.initials: JT
authors.lastname: Suh
authors.forename: You Sun
authors.initials: YS
authors.lastname: Nam
authors.forename: Mi Suk
authors.initials: MS
authors.lastname: Lee
authors.forename: Hee Joo
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015897:Comorbidity; D005260:Female; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D015999:Multivariate Analysis; D010045:Outpatients / Q000706:statistics & numerical data*; D058873:Pandemics / Q000706:statistics & numerical data*; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D055815:Young Adult