LAUSR

It is well known that respiratory syncytial virus (RSV) and rhinovirus infections can cause bronchiolitis and are associated with recurrent wheeze. There are three species of rhinovirus, A, B and C, and evidence is accumulating that rhinovirus C infection is more severe and more likely to cause subsequent wheeze. A multicentre US study identified 716 infants admitted with bronchiolitis from 2011 to 2014; 541 (76%) had RSV infection alone, 85 (12%) had rhinovirus A, 12 (2%) rhinovirus B and 78 (11%) rhinovirus C. By 3 years of age, 231 (32%) had recurrent wheezing, the main outcome measure. Recurrent wheeze was not significantly different in infants with rhinovirus A or B infection compared with RSV infection (rhinovirus A: hazard ratio (HR) = 1.27; 95% confidence interval (CI) 0.86–1.88; rhinovirus B: HR = 1.39; 95% CI 0.51–3.77). In contrast, infants with rhinovirus C had a significantly higher risk of recurrent wheeze (HR = 1.58; 95% CI 1.08–2.32). Infants with both rhinovirus C infection and IgE sensitisation to food or aeroallergens had even higher risk of recurrent wheeze (HR = 3.03; 95% CI 1.20–7.61). Furthermore, compared with RSV, rhinovirus C infection with IgE sensitisation was associated with significantly higher risk of asthma at 4 years of age (HR = 4.06; 95% CI 1.17–14.1). Although a less common cause of severe bronchiolitis and recurrent wheeze than RSV, rhinovirus C is clearly an important pathogen for infants.