Correlation of viral load as determined by real-time RT-PCR and clinical characteristics of respiratory syncytial virus lower respiratory tract infections in early infancy

J Clin Virol. 2008 Jan;41(1):45-8. doi: 10.1016/j.jcv.2007.10.018. Epub 2007 Dec 21.


Background: In infants hospitalized for a lower respiratory tract infection (RTI) caused by respiratory syncytial virus (RSV), the correlation between viral load (VL) and patient clinical characteristics remains to be defined.

Objectives: To define this correlation.

Study design: prospective study of 47 infants admitted to hospital in the period November 2006-May 2007 with a diagnosis of lower RTI. Nasopharyngeal aspirates (NPAs) were taken at admission, discharge, and at post-discharge control visits. VL was quantified by real-time RT-PCR for RSV subgroups A and B.

Results: Patients with bronchiolitis were compared with young patients with lower RTI other than bronchiolitis. Patients with bronchiolitis had a significantly lower age than patients with other syndromes, and a significantly longer duration of symptoms. Duration of hospitalization was not different in the two groups of patients, and was not related to RSV subgroup or viral coinfection. A sustained decrease in VL was observed in the general patient population between admission, discharge and post-discharge follow-up visits.

Conclusions: (i) patients with bronchiolitis were significantly younger than patients with other lower RTIs; (ii) symptom duration was significantly longer in patients with bronchiolitis; (iii) RSV VL significantly decreased between admission and discharge.

Publication types

  • Comparative Study

MeSH terms

  • Age Factors
  • Bronchiolitis / physiopathology
  • Bronchiolitis / virology
  • Child, Preschool
  • Humans
  • Infant
  • Infant, Newborn
  • Pharynx / virology
  • Prospective Studies
  • RNA, Viral / genetics
  • Respiratory Syncytial Virus Infections / physiopathology*
  • Respiratory Syncytial Virus Infections / virology*
  • Respiratory Syncytial Viruses / genetics
  • Respiratory Syncytial Viruses / isolation & purification*
  • Respiratory Tract Infections / physiopathology*
  • Respiratory Tract Infections / virology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Time Factors


  • RNA, Viral