Study population
We used de-identified data sourced from three prospective studies undertaken between June 2008 and September 201319-21. For this study, we included only the 232 Indigenous infants living in the Northern Territory (Australia). Here we briefly describe these studies; two were randomised controlled trials (RCT) where we found neither single or 3-weekly azithromycin (single or 3-weekly) doses, compared to placebo, improved any clinical outcomes for infants hospitalised with bronchiolitis19,20. The third was a cohort study to determine the validity and reliability of a bronchiolitis scoring system of infants hospitalised with bronchiolitis21. An overview of the studies is further described in the Figure. The local Human Research Ethics Committee approved each original study (HREC 07/60, HREC-2010-1324) and written informed consent obtained from the primary carer. In all studies19-21, infants were aged ≤24-months hospitalised with a diagnosis of bronchiolitis using a standardised hospital protocol, with the same exclusion criteria (detailed in E-text).