Role of rhinovirus in hospitalized infants with respiratory tract infections in Spain

Background: Rhinovirus is a recognized cause of common cold, proven to cause asthma exacerbations in children. In Spain, no description exists, as yet, as to the degree of burden rhinovirus infections represent among hospitalized infants. Our aim was to describe rhinovirus infections in hospitalized children, under 2 years of age, and to compare these with patients infected with respiratory syncytial virus (RSV). Patients and Methods: The prospective study was performed between September 2003 and July 2005, in children < 2 years of age, admitted at the Severo Ochoa Hospital (Leganes, Madrid) with fever or respiratory tract infection and with positive rhinovirus detection in the nasopharyngeal aspirate samples. Virologic diagnosis was made by multiplex reverse transcription-polymerase chain reaction and for some virus by direct immunofluorescent assay in nasopharyngeal samples. Demographic and clinical data of those patients with rhinovirus infection were described and compared with a group of 86 patients, infected only with RSV, randomly selected from the same population. Results: We detected 85 children admitted to hospital with rhinovirus infection. Rhinovirus was the cause of 25% of all admissions, among the total of 340 under 2-year olds diagnosed with fever or respiratory tract infection. Rhinovirus was the second viral agent identified, after RSV. Clinical diagnosis was recurrent wheezing in 48.2%; bronchiolitis in 36.5%; and pneumonia in 3.5%. Fever was present in 60% of the patients. Radiologic infiltrates were found in 22.4% of the children. In 50.6% of the infants, oxygen saturation under 95% was detected, at the time of admission. Hypoxia was present in RSV-infected children more frequently (P = 0.005). Also, in this group, final diagnosis was, most frequently, bronchiolitis (P = 0.0001), and rhinovirus-infected patients were most frequently males (P = 0.004). Conclusions: Rhinovirus was detected in hospitalized infants with respiratory tract disease and was the second most common virus after RSV. In our experience, it was the second etiologic agent associated with recurrent wheezing in hospitalized children, under the age of 2 years.