After 8 years of recruitment to this study, Schuh S et al [JAMA 2020;324:2038–2047 doi:10.1001/jama.2020.19839] have reported the results of this randomised, double blind, placebo controlled parallel group controlled trial. PERC (Paediatric Emergency Research Network of Canada) is a large research network and some of their members, recruited children between 2011 and 2019, in seven tertiary-care paediatric emergency departments. The participants were previously healthy children aged 2 to 17 years with moderate to severe asthma defined by a Paediatric Respiratory Assessment Measure (PRAM) score of 5 or greater (on a 12-point scale) after a 1 hour treatment with an oral corticosteroid …