Prevalence of viral respiratory tract infections in children with asthma

BackgroundPrevious studies support a strong association between viral respiratory tract infections and asthma exacerbations. The effect of newly discovered viruses on asthma control is less well defined.ObjectiveWe sought to determine the contribution of respiratory viruses to asthma exacerbations in children with a panel of PCR assays for common and newly discovered respiratory viruses.MethodsRespiratory specimens from children aged 2 to 17 years with asthma exacerbations (case patients, n = 65) and with well-controlled asthma (control subjects, n = 77), frequency matched by age and season of enrollment, were tested for rhinoviruses, enteroviruses, respiratory syncytial virus, human metapneumovirus, coronaviruses 229E and OC43, parainfluenza viruses 1 to 3, influenza viruses, adenoviruses, and human bocavirus.ResultsInfection with respiratory viruses was associated with asthma exacerbations (63.1% in case patients vs 23.4% in control subjects; odds ratio, 5.6; 95% CI, 2.7- 11.6). Rhinovirus was by far the most prevalent virus (60% among case patients vs 18.2% among control subjects) and the only virus significantly associated with exacerbations (odds ratio, 6.8; 95% CI, 3.2-14.5). However, in children without clinically manifested viral respiratory tract illness, the prevalence of rhinovirus infection was similar in case patients (29.2%) versus control subjects (23.4%, P > .05). Other viruses detected included human metapneumovirus (4.6% in patients with acute asthma vs 2.6% in control subjects), enteroviruses (4.6% vs 0%), coronavirus 229E (0% vs 1.3%), and respiratory syncytial virus (1.5% vs 0%).ConclusionSymptomatic rhinovirus infections are an important contributor to asthma exacerbations in children.Clinical implicationsThese results support the need for therapies effective against rhinovirus as a means to decrease asthma exacerbations.