A clinical respiratory assessment of the first bronchiolitis episode based on lung-X-rays, respiratory outcomes (hypoxemia, wheezing, and/or sub-costal retractions), nasal protein levels of antiviral and type 2 cytokines (IFNγ, IL-10, IL-4, IL-13, IL-1β, and TNFα) was conducted also by Arroyo et al. (37) in 2020 to define mild, hypoxemia or wheezing phenotypes. Here, IL4 is linked to bronchiolitis.