The results from this large pragmatic study indicate that the addition of nebulised HS to good supportive care when treating infants admitted to hospital with acute bronchiolitis does not appear to cause any harm but confers no benefit. The economic analysis used two forms of analysis to consider the cost-effectiveness of nebulised HS in this patient population. A CUA based on hospital costs and patient health-related quality of life suggests a 34% chance that the intervention is cost-effective and an ICER of £7.6M per QALY is gained. This figure is generated by an estimated additional cost associated with the intervention and an estimated incredibly small additional patient benefit, both of which are highly uncertain. Based on this analysis, the intervention cannot be considered either clinically effective or cost-effective in the UK health context. Taking a broader view of benefits that includes any of the primary and secondary outcomes measures does not appreciably alter this conclusion, as only one statistically significant difference between the study arms is apparent with that result being open to considerable biases. Our updated systematic review suggests that there is too much heterogeneity to make a pooled estimate of effect across 13 studies of inpatient care a useful basis for decision-making and shows that large studies, and those from northern Europe, have negative results which support the findings of the SABRE study.