Comorbid Asthma Within A Prospective Household Study Of Respiratory Viral Infections

Viral upper respiratory infection is a common trigger of asthma exacerbations. We hypothesized that households with asthmatic members would have an overall higher burden of viral respiratory disease with longer duration of illness, more severe symptoms and greater transmission between household members in comparison to households without asthmatic members. 1171 subjects (119 with asthma) were enrolled by household (n=303) in a prospective longitudinal study of respiratory viral infections in Seattle, WA, USA from November 2019 through April 2020. Subjects self-reported sociodemographic data, symptoms, severity, and underlying comorbidities. At the onset of respiratory symptoms, individuals self-collected a mid-nasal swab and completed a symptom log. Swabs underwent RT-PCR testing for eight common respiratory viruses including RSV, rhinovirus, influenza and SARS-CoV-2. 592 respiratory illness episodes (77 complicated by asthma) were reported with 40 secondary detections of virus in 33 of 207 households with illness. No significant difference was observed in secondary viral detection within household by asthma status, adjusted by household size (t-test). Individuals with asthma were more likely to report shortness of breath (p=0.001), without significantly increased overall illness duration or self-reported severity. Individuals with asthma had a lower rate of viral detection for symptomatic illness (34% versus 50%, p=0.01, χ2 test). No significant difference in viral spread or duration of illness within households by asthma status was noted. Household members with asthma were more likely to have a symptomatic illness without an isolated viral pathogen, suggesting a different cause of acute illnesses.