RATIONALE: The role of rhinovirus (HRV)-induced wheezing compared to HRV-induced upper respiratory illness (URI) in school-aged children with underlying asthma has not been determined.
METHODS: We performed a case-control study of 5-18 year-old asthmatic children in Baltimore and Buenos Aires presenting with active wheezing and controls presenting with URI in the absence of wheezing. Respiratory specimens were tested by MultiCode-Plx Assay for HRV, respiratory syncytial virus, parainfluenza viruses, influenza viruses, human metapneumovirus, adenoviruses and coronaviruses. Specimens were also tested by real-time RT-PCR for HRV. To determine the HRV clade, the VP4/VP2 gene was sequenced from HRV-positive specimens.
RESULTS: Of 478 samples from children enrolled and tested, 44.3% were positive for HRV and 17.5% were positive for other viruses. During the 2-year study period, HRV infection was associated with exacerbations (54% case vs 36.7% control, p2 prior asthma hospitalizations were at greater risk of wheezing compared to those with < 2 of prior asthma hospitalizations (p<0.001; OR=2.59,95%CI1.62-4.14). Moderate to severe baseline asthma severity was associated with less acute wheezing (p<0.001, OR=0.17, CI=0.1-0.3), and use of inhaled corticosteroids was associated with less acute wheezing (46.7% cases vs 61% controls, p=0.002).
CONCLUSIONS: Human rhinoviruses may precipitate wheezing, preferentially, over URI alone, in school-aged children with underlying asthma. HRV infection, mild baseline severity and > 2 previous asthma hospitalizations are risk factors for wheezing exacerbations among asthmatics. The use of inhaled corticosteroids is protective for acute wheezing in asthmatic children.
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