ab Evans 1976.

Methods	Randomised controlled trial
Participants	162 healthy participants aged 18 to 61 years
Interventions	Bivalent live attenuated vaccine WRL 105 (recombinant of A/Okuda/57 and A/Finland/4/74) containing 107.0 EID50 virus/0.5 mL dose versus placebo. Both preparations were administered intranasally 3 to 4 weeks apart.
Outcomes	Reactions to immunisation were observed for 7 days after each dose. Local symptoms (referable to the upper respiratory tract, mainly nasal obstruction, nasal discharge, or sore throat) reported as mild, moderate, or severe. General symptoms (mainly headache, fever, or myalgia). Local and general symptoms are further reported in different intensity classes (mild, moderate, severe, lasting for at least 4 days) reported as mild, moderate, or severe. Use of analgesics.
Notes	Safety data only were extracted. Funding source ‐ mixed
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