PSMA6 and hepatitis A virus infection: The reasons for patient exclusion were: 5 had underlying conditions (e.g. cerebral palsy, alpha-1-antitrypsin deficiency, hepatitis A, and congenital cystic adenomatoid malformation), and 3 had a clinical history incompatible with pneumonia (i.e. respiratory symptoms on hospital admission were better accounted for by conditions such as severe reactive airway disease, croup, or aspiration).