Overview of methods
cough
LRTI
Full details of all data-collection methods have been previously published.Acute LRTI was defined syndromically in several previous cohorts and trials as an acute cough as the predominant symptom, judged by the GP to be infective in origin, lasting <21 days (which will exclude children with protracted bacterial bronchitisWhere parents and clinicians were willing for children to be randomised, they were randomised to receive amoxicillin 50 mg/kg/day in divided doses for 7 days or placebo using pre-prepared packs randomised using a computer-generated random number by an independent statistician.Children not randomised (because they were ineligible or because of clinician or parent choice) were invited to participate in an observational study where the baseline clinical data and all outcome data as for the trial were collected by the same methods.