Berger 1998.

Methods	Parallel design, 2‐arm Single‐centre, conducted in Israel (affiliations: Shaare Zedek Medical Center, Jerusalem)
Participants	Outpatients (emergency department) Inclusion/exclusion criteria Inclusion criteria: age ≤ 18 months; 1st episode of wheezing associated with low‐grade fever, rhinitis, tachypnoea and increased respiratory effort; otherwise healthy infant Exclusion criteria: chronic cardiopulmonary disease; asthma; proven or suspected acute bacterial infection; previous therapy with glucocorticoids; symptoms > 7d; fever > 38.5°C; severe bronchiolitis (clinical score > 7) Participant characteristics All groups Sample size: randomised (N): 42, analysed ‐ trial/review primary outcomes (N): 38 (per protocol analysis was used) GROUP 1 Sample size: randomised (N): NR, analysed ‐ trial/review primary outcomes (N): 20 Age, mean ± SD: 5.2 ± 0.7 Males, N (%): NR RSV status: 50% positive Atopic status: 1/20 (infant), 3/20 (family) GROUP 2 Sample size: randomised (N): NR, analysed ‐ trial/review primary outcomes (N): 18 Age, mean ± SD: 4.8 ± 0.9 Males, N (%): NR RSV status: 50% positive Atopic status: 0 (infant), 4/20 (family)
Interventions	GROUP 1 (with glucocorticoid) Drug name: prednisone Dose: 1 mg/kg Mode of administration: oral Timing/duration: twice daily, 3 days GROUP 2 Drug name: placebo (NR) Dose: 1 mg/kg Mode of administration: oral Timing/duration: twice daily, 3 days Additional co‐interventions for all groups: inhaled albuterol solution 0.03 mL/kg/dose (0.15 mg/kg/dose) every 4 to 6 hours; O2 and hydration as needed Protocolised use of bronchodilators with glucocorticoids: yes (salbutamol)
Outcomes	Primary outcome NR Outcome used to calculate sample size Clinical scale developed for this trial ‐ 9‐point score, based on respiratory rate, wheezing, accessory muscle use Secondary outcomes Initial hospital admission (usually within 4 h); SaO2*; respiratory rate*; well‐being#; return healthcare visits#; medications#; recurrent symptoms (by 2 years) *time points: baseline, 3 days #time points: 7 days
Funding	NR
Notes	Study did not report any study‐level subgroup analyses This study contributed to the following comparisons in this review: steroid versus placebo
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomization was made according to a standardized statistical method"
Allocation concealment (selection bias)	Low risk	"Upon enrolment, each patient was randomly assigned by a research pharmacist"; "neither the investigators nor the families were aware of treatment assignments."
Blinding (performance bias and detection bias) Health care use ((re)admissions, LOS, return visits)	Low risk	"The solutions provided by the pharmacy appeared identical, and neither the investigators nor the families were aware of treatment assignments." "The examiner was blind to what treatment the patient had received."
Blinding (performance bias and detection bias) Clinical parameters (severity scales, SpO2, respiratory and heart rate)	Low risk	"The solutions provided by the pharmacy appeared identical, and neither the investigators nor the families were aware of treatment assignments." "The examiner was blind to what treatment the patient had received."
Blinding (performance bias and detection bias) Patient/parent‐reported outcomes (symptoms, QoL)	Low risk	"The solutions provided by the pharmacy appeared identical, and neither the investigators nor the families were aware of treatment assignments." "The examiner was blind to what treatment the patient had received."
Incomplete outcome data (attrition bias) Health care use ((re)admissions, LOS, return visits)	Unclear risk	Number completing treatment specified for each group; total of 4 drop‐outs, unclear what were the specific motives and to which arm they were assigned to
Incomplete outcome data (attrition bias) Clinical parameters (severity scales, SpO2, respiratory and heart rate)	Unclear risk	Number completing treatment specified for each group; total of 4 drop‐outs, unclear what were the specific motives and to which arm they were assigned to
Incomplete outcome data (attrition bias) Patient/parent‐reported outcomes (symptoms, QoL)	Unclear risk	Number completing treatment specified for each group; total of 4 drop‐outs, unclear what were the specific motives and to which arm they were assigned to
Selective reporting (reporting bias)	Low risk	Published report includes all pre‐specified and expected outcomes; the study protocol was not available
Other bias	Low risk	No significant baseline imbalances; no other sources of bias
Overall risk of bias	Unclear risk	> 1 domain as unclear risk of bias