Abstract
Background:
Acute viral bronchiolitis is the most common cause of hospitalization in infants worldwide. Respiratory syncytial virus (RSV) is detected in a majority of patients, followed by human rhinovirus (HRV) and human metapneumovirus (MPV). The possible association between viral load detected and disease severity is unclear.
Methods:
In a multicenter clinical trial of bronchiolitis treatment in two consecutive winter seasons, nasopharyngeal aspirate was sampled from 363 subjects (62% boys, mean age 4.2 months) and analyzed by real-time PCR detection of RSV, MPV and HRV.
Semi quantitative clusters (1-3, 1 highest) of virus load were constructed for each virus based on the PCR threshold cycles (0-20) by using K-means clustering.
Results:
Mean (95 % confidence interval) estimated LOS was 80.6 (73.8-87.3) hours for all 363 children with no significant differences i LOS by viruses detected; 78.9 (71.6-86.3) in children with RSV, 75.6 hours (71.6-86.3) for MPV and 82.6 hours (70.5-94.8) for HRV. Among children with RSV detected (81%), increasing viral load was associated with longer length of stay
(estimated in robust linear regression analyses adjusted for age to 16.3 hours for a change from a lower to a higher cluster level, p=0.02). No associations were found between LOS and viral level cluster within HRV or MPV.
Conclusion:
In patients hospitalized with moderate to severe acute bronchiolitis, RSV load is positively associated with length of stay.
- © 2014 ERS