ab Lauteria 1974.

Methods	Controlled trial. Randomisation procedure was neither described nor mentioned. Participants were paired according to age and sex, 1 participant in each pair received vaccine, the other placebo. Double‐blind
Participants	37 volunteers aged 18 to 24 years, with titre of serum neutralising antibodies to A/Hong Kong/8/68 > 1:16
Interventions	Live attenuated A/England/8/68 grown in presence of heated equine serum. Two 0.5 mL doses containing 104 TCID50 of this strain or placebo (0.85% sodium chloride) were administered intranasally 2 to 3 weeks apart
Outcomes	Participants observed for 4 days, beginning 24 hours after immunisation. Fever, myalgia, rhinitis, cough, pharyngitis
Notes	Safety data only were extracted. Government and industry funded
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Unclear
Allocation concealment (selection bias)	Unclear risk	Unclear
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Unclear
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear
Summary assessment	Unclear risk	Unclear