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. Author manuscript; available in PMC: 2024 Oct 1.
Published in final edited form as: J Allergy Clin Immunol. 2023 Aug 19;152(4):866–869. doi: 10.1016/j.jaci.2023.08.009

Figure 1.

Figure 1.

Confounding effect from shared heredity on the association between RSV bronchiolitis and childhood asthma. “A” represents the association in observational studies examining the role of RSV bronchiolitis (*) or some other marker of early life severe RSV disease (such as RSV lower respiratory tract infection requiring hospitalization) on childhood asthma. “B” represents the shared role of host genetics on both RSV bronchiolitis and childhood asthma, an important confounder of the association that cannot be easily controlled. Thus, in observational studies of RSV bronchiolitis and childhood asthma, paths “A” and “B” cannot be differentiated. “C” represents an approach of examining the association between RSV infection in infancy (and not only RSV bronchiolitis) and childhood asthma to overcome several limitations of prior studies, including shared heredity and measuring an exposure rather than a clinical phenotype. Definition of abbreviation: RSV = respiratory syncytial virus.