Figure 2.

Association among respiratory viruses, atopy, wheeze, and asthma. As discussed in the text, respiratory syncytial virus (RSV) has been strongly associated with the development of wheeze in infants who have had a severe infection but without any preexisting atopy. Less clear (dashed lines) are the association between RSV infection and development of atopy, as well as asthma by adolescence. Rhinovirus (RV), on the other hand, drives the development of wheeze and asthma but only in the presence of preexisting atopy. There is an unclear association with the factors that drive atopic and nonatopic asthma (dotted lines). Viral infections, including with RV or RSV, are also able to exacerbate existing asthma.