Chen 2006.

Methods	Randomised controlled trial. Conducted in paediatric hospital in China. 62 children enrolled (observation group = 32, control group = 30). Randomly split into study groups Dose of IVIG/placebo used: 400 mg/kg/day for 3‐5 days. Outcome assessment done during period of hospitalisation.
Participants	Inclusion criteria Aged 8 months to 12 years. Diagnosis of viral encephalitis as described in "Applied Pediatrics" 6th edition. Exclusion criteria Not mentioned.
Interventions	Control group: conventional treatment including fever and spasm reduction, reduction of intracranial pressure, maintenance of hydration, electrolyte and acid‐base balance, antiviral treatment, treatment of infections. Observation group: conventional treatment as above + IVIG 400 mg/kg/day continuously for 3‐5 days.
Outcomes	Time for fever reduction. Time taken to stop further spasms. Time taken to regain consciousness. Duration of hospital stay.
Notes	No information on ethical approval or informed consent. No information provided on funding.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Random allocation but method of randomisation not described.
Allocation concealment (selection bias)	Unclear risk	No information provided.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No information provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts and all participants were included in outcome assessment.
Selective reporting (reporting bias)	Unclear risk	Study protocol not available in public domain.
Other bias	Unclear risk	Small sample size and no sample size calculation so unclear if sample size large enough to detect significant differences between study groups. No information on funding provided.