To determine whether hospital length of stay (LOS) for acute bronchiolitis is influenced by the infecting pathogen.
A prospective observational cohort study was performed during 3 consecutive years.
Sixteen US hospitals participated in the study.
Children younger than 2 years hospitalized with bronchiolitis were included.
The results of nasopharyngeal aspirate polymerase chain reaction pathogen testing served as the main exposure.
Main Outcome Measure
Hospital LOS was determined.
Of 2207 participants, 72.0% had respiratory syncytial virus (RSV) and 25.6% had human rhinovirus (HRV); the incidence of each of the other viruses and bacteria was 7.8% or less. Multiple pathogen infections were present in 29.8% of the children. There were 1866 children (84.5%) with RSV and/or HRV. Among these 1866 children, the median age was 4 months and 59.5% were male. The median LOS was 2 days (interquartile range, 1-4 days). Compared with children who had only RSV, an LOS of 3 or more days was less likely among children with HRV alone (adjusted odds ratio [AOR], 0.36; 95% CI, 0.20-0.63; P < .001) and those with HRV plus non-RSV pathogens (AOR, 0.39; 95% CI, 0.23-0.66; P < .001) but more likely among children with RSV plus HRV (AOR, 1.33; 95% CI, 1.02-1.73; P = .04), controlling for 15 demographic and clinical factors.
In this multicenter study of children hospitalized with bronchiolitis, RSV was the most common virus detected, but HRV was detected in one-quarter of the children. Since 1 in 3 children had multiple virus infections and HRV was associated with LOS, these data challenge the effectiveness of current RSV-based cohorting practices, the sporadic testing for HRV in bronchiolitis research, and current thinking that the infectious etiology of severe bronchiolitis does not affect short-term outcomes.