Abstract: In this review update, we added one study with 219 children. A total of two RCTs with 249 children (n = 240 completed) were eligible for inclusion in this review. Both studies contributed to our primary and secondary outcomes, but we assessed the quality of evidence for our three primary outcomes as low, owing to the small numbers of studies and participants; and high attrition in one of the studies. Data show no significant differences between treatment groups for our primary outcomes: proportion of children (n = 249) who had persistent symptoms at follow-up (odds ratio (OR) 0.69, 95% confidence interval (CI) 0.37 to 1.28; fixed-effect model); and number of children (n = 240) rehospitalised with respiratory illness within six months (OR 0.54, 95% CI 0.05 to 6.21; random-effects model). We were unable to analyse exacerbation rate because studies used different methods to report this information. Data showed no significant differences between treatment groups for our secondary outcome: proportion of children (n = 240) with wheeze at six months (OR 0.47, 95% CI 0.06 to 3.95; random-effects model). One study reported bacterial resistance, but only at 48 hours (thus with limited applicability for this review). Another study reported adverse events from which all children recovered and remained in the study. Current evidence is insufficient to inform whether antibiotics should be used to treat or prevent persistent respiratory symptoms in the post-acute bronchiolitis phase. Future RCTs are needed to evaluate the efficacy of antibiotics for reducing persistent respiratory symptoms. This is particularly important in populations with high acute and post-acute bronchiolitis morbidity (e.g. indigenous populations in Australia, New Zealand, and the USA).

Plain-language summary: This review update (up to 26 August 2016) includes two clinical trials that compared antibiotics with placebo for children in the post-acute bronchiolitis phase (> 14 days). The first was reported from Turkey and enrolled 30 infants aged seven months or younger. The second was reported from Australia and New Zealand and enrolled 249 infants aged 24 months or younger. Both trials initiated treatment during hospitalisation for bronchiolitis and provided follow-up for six months post hospitalisation. This review update includes a total of two trials with 249 children (n = 240 completed). Both studies contributed to primary and secondary outcomes, but the quality of evidence was low. Review authors noted no significant differences between treatment groups for our primary outcomes: proportion of children (n = 249) who had persistent symptoms at follow-up, and number of children (n = 240) rehospitalised with respiratory illness within six months; nor for our secondary outcome: proportion of children (n = 240) with wheeze at six months. One study reported bacterial resistance, but only at 48 hours. One study reported adverse events from which all children recovered and remained in the study. Currently, not enough evidence is available to inform whether antibiotics should be used to treat or prevent persistent respiratory symptoms in the post-acute phase of bronchiolitis. Clinical trials are needed to evaluate the efficacy of antibiotics for reducing persistent respiratory symptoms, especially in countries where morbidity of bronchiolitis is high (e.g. indigenous populations).