title: Viral load and clinical features in children infected with seasonal influenza B in 2006/2007.
abstract: OBJECTIVE
  In influenza B infection, viral load is believed to be related to the severity of clinical illness. The correlation between viral load and symptoms is not known. We conducted a study to assess the relationship between virus load and clinical features in children infected with influenza B, in the hope that clinical features could be used as surrogate markers of viral load to guide treatment.
  
  
  METHODS
  Between December 2006 and February 2007, 228 patients with fever and respiratory symptoms were prospectively enrolled in our tertiary hospital-based study. Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to determine viral load.
  
  
  RESULTS
  Real-time RT-PCR was positive for influenza B in 76 patients. Using virus culture as the gold standard, the sensitivity and specificity were 95% and 87%, respectively. Influenza culture positive rate significantly correlated with viral load (p = 0.03). The median copy number of influenza B virus in the 76 RT-PCR positive patients was 9735 copies/ml (range 4.8×10¹-2.0×10⁶ copies/ml). Samples obtained later in the clinical course tended to have lower viral load (p = 0.7), while patient age (p = 0.72) and fever duration (p = 0.96) positively related to viral load. In patients >3 years of age, myalgia was related to statistically lower viral loads (14300 vs. 1180; p = 0.025). Patients with chills tended to have higher viral loads (72450 vs. 7640; p = 0.1). Patients with abdominal pain tended to have lower viral loads (1998 vs. 12550; p = 0.06).
  
  
  CONCLUSIONS
  Culture rate positively correlated with viral load. Patients with myalgia had a lower viral load.
authors.affiliation: Research and Diagnostic Center, Centers for Disease Control, Taipei, Taiwan.
authors.forename: Tsung-Pei
authors.initials: TP
authors.lastname: Tsou
authors.forename: Pei-Lan
authors.initials: PL
authors.lastname: Shao
authors.forename: Chun-Yi
authors.initials: CY
authors.lastname: Lu
authors.forename: Luan-Yin
authors.initials: LY
authors.lastname: Chang
authors.forename: Chuan-Liang
authors.initials: CL
authors.lastname: Kao
authors.forename: Ping-Ing
authors.initials: PI
authors.lastname: Lee
authors.forename: Pan-Chyr
authors.initials: PC
authors.lastname: Yang
authors.forename: Chin-Yun
authors.initials: CY
authors.lastname: Lee
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Huang
mesh_terms: D015746:Abdominal Pain / Q000821:virology; D000293:Adolescent; D000367:Age Factors; D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D023341:Chills / Q000821:virology; D005260:Female; D005334:Fever / Q000821:virology; D006801:Humans; D007223:Infant; D009981:Influenza B virus / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000821:virology; D008297:Male; D059352:Musculoskeletal Pain / Q000821:virology; D053139:Oseltamivir / Q000627:therapeutic use; D011446:Prospective Studies; D012367:RNA, Viral / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D012367:RNA, Viral; D053139:Oseltamivir