title: Clinical and laboratory analysis of influenza B infection in children in Taichung, Taiwan during the 2006-2007 flu season.
abstract: BACKGROUND
  An epidemic of influenza B/Malaysia/2506/2004 was reported in Taiwan during the 2006-2007 flu season. We investigated the flu vaccination history and clinical and Laboratory characteristics of children with influenza B infection.
  
  
  METHODS
  We enrolled children younger than 18 years old who visited one of two hospitals between November 2006 and February 2007 with influenza-like illnesses. Throat swabs were taken on their first visit and cultured for viruses. Complete and differential blood counts and blood biochemical parameters were analyzed in some children.
  
  
  RESULTS
  Influenza virus was cultured from 51.0% of patients (101/198), 87 (86.1%) of who were infected with influenza virus type B. The remaining 14 (13.9%) were infected with influenza virus type AH3. The 87 children (median age 7.8 years) with culture-proven influenza B virus infection were enrolled. Nine parents reported that enrolled children had been vaccinated against influenza. Leukopenia was found in 56.1% (32/57) of patients, leukocytosis in 3.5% (2/57), and thrombocytopenia in 1.8% (1/57). Thirteen of 23 patients (56%) tested for creatine kinase (CK) had elevated levels ( >160 U/L), and 11 of 23 (47.8%) had myalgia associated with raised CK (p < 0.05). Twenty-six children developed complications, including one case of pneumonia with acute respiratory distress syndrome and one case of flu-associated encephalitis.
  
  
  CONCLUSIONS
  Most children who contracted influenza B infection had not been vaccinated. Almost half the children had leukopenia, and some had leukocytosis, but thrombocytopenia was rare. There was a significant association between raised CK levels and myalgia in influenza B infection.
authors.affiliation: Department of Pediatrics, Miaoli General Hospital, Department of Health, The Executive Yuan, Miali, Taiwan.
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Wang
authors.forename: Po-Yen
authors.initials: PY
authors.lastname: Chen
authors.forename: Jiann-Der
authors.initials: JD
authors.lastname: Wang
authors.forename: Fang-Ching
authors.initials: FC
authors.lastname: Liu
authors.forename: Fang-Liang
authors.initials: FL
authors.lastname: Huang
authors.forename: Chun-Yi
authors.initials: CY
authors.lastname: Lee
mesh_terms: D002648:Child; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000150:complications / Q000821:virology; D013624:Taiwan