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

Abstract

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.