Respiratory viral infections in children with asthma: do they matter and can we prevent them?

Ahanchian, Hamid; Jones, Carmen M; Chen, Yueh-sheng; Sly, Peter D

Each year, at the end of summer, parents of asthmatic children are concerned about acute asthma exacerbations following a common cold, asking how to minimize the risk during the winter viral season. It is a valid concern as up to 70% of asthmatic children have an intermittent or wheeze which is mostly symptomatic after viral infections [25, 26] . Asthmatics with exacerbationprone phenotype are susceptible to acute exacerbations requiring hospitalization or an unscheduled visit for medical attention. Major risk factors for acute exacerbations include previous acute exacerbation, allergy, young age, poorly controlled asthma, and, in particular, viral respiratory infections. Moreover, recent data suggests an interaction between allergies and viral infections occurs to increase the risk of asthma exacerbation [27] . Acute exacerbations are associated with decreased lung growth or accelerated loss of lung function and, as such, add substantially to both the cost and morbidity associated with asthma [28, 29] . Viral respiratory infections are the main cause of asthma exacerbations in children (80-85%) and are a major risk factor for admission in hospital every autumn [30] [31] [32] . HRV are the most common viral agents [33] ; Other respiratory tract viruses detected in children with an asthma exacerbation include RSV, influenza, coronavirus, hMPV, parainfluenza virus, adenovirus, and bocavirus [34] [35] [36] . Current drugs for the prevention and treatment of virus-induced exacerbation of asthma are poorly effective and novel alternative therapies are needed.