Viral Infections and Associated Factors That Promote Acute Exacerbations of Asthma

Kim, Chang-Keun; Callaway, Zak; Gern, James E.

Viral identification in early childhood wheezing illness may provide prognostic information regarding short-and long-term consequences. In the short term, RSV-induced bronchiolitis is associated with longer hospitalization than RV-induced bronchiolitis. 20 The risk of reinfection with certain viruses varies; for example, there is a strong likelihood of RSV reinfection in the absence of ongoing passive immunity. 21 Two studies found this risk to be as high as 74% 22 and 76% 23 if the initial infection occurred within the first year of life. Fourth, certain respiratory viruses have a well-documented association with subsequent asthma development and then exacerbation. More severe RSV illnesses in early childhood increase the risk of asthma development, 24 and the risk for developing asthma is even greater after a RV wheezing episode in early life. 25 Some children may have genetic risk factors for wheezing with RV 26 or with RSV. RV and EV infections also contribute to exacerbations of asthma, especially in children. 11 Notably, many commonly used polymerase chain reaction (PCR)-based tests cannot distinguish RV from other EV (e.g., EV-D68). 19 Viral sequencing analysis to specifically identify EV-D68 can be performed. 27