RecruitingDiagnostic testThe Rhinovirus Hospitalization and Investigation of Nasal-airway Omics (RHINO) StudyThe goal of this study is to determine the burden of Rhinoviruses (RVs) as a cause of acute, severe, respiratory illnesses leading to hospitalization. A community cohort of 120 children between 12 and 36 months of age will be enrolled in the first year of the study and followed (when well and sick) for 36 months to identify the circulating RVs and provide samples to establish a host nasal transcriptome differentiating clinical from subclinical RV infections. A hospitalized cohort of 450 infants and children will be enrolled during years 1 through 3 of the study and followed for the duration of their hospitalization to investigate the findings of the community cohort. An additional 100 healthy children aged 5-17.5 years will be enrolled for age-match comparison with the older hospitalized cohort.