IFNA1 and bronchiolitis: Descriptively, infants with an endotype A were characterized by “classic” clinical presentation of bronchiolitis (e.g., young age, a low proportion of previous breathing problems and parental asthma, the high proportion of solo-RSV infection), higher abundance of M. nonliquefaciens, and intermediate IFN-α and -γ response (Table 1 and Figs. 2–5).