Infections and Asthma: Impact on the Natural History of Asthma

• Wheezing viral respiratory illnesses are the most common initial presentation of childhood asthma. • Once asthma is established, viral infections, most notably rhinovirus (RV), are the most frequent trigger of severe asthma exacerbations. RV-C appears to be a particularly pathogenic virus in children with asthma. • Evidence has recently emerged to suggest that bacterial pathogens in the lower airway may contribute to the expression of asthma. Ongoing studies are critical to our understanding of the role of the airway microbiome in asthma inception and exacerbation. • Synergistic interactions between underlying allergy and virus infections play an important mechanistic role in asthma inception and exacerbation, and are an important therapeutic target. • Novel therapies are needed to prevent and treat virus-induced wheezing and asthma exacerbations.