ab Keitel 1993a.

Methods	"The two trials (Keitel 1993a and Keitel 1993b) tested three live attenuated vaccines." This paper reports the results of 2 randomised controlled trials carried out in the USA
Participants	Healthy volunteers recruited at Texas A&M University and Texas Medical Center, aged between 18 and 40 years
Interventions	Two 0.5 mL doses of cold‐adapted recombinant influenza vaccines, 1 month apart, containing 107.1 TCID50 of each strain/dose. 2 studies were conducted in which 4 groups were formed (2 interventions, 2 placebos): 1) placebo 1st and 2nd dose. 2) 1st: A/Kawasaki/9/86 (H1N1, CR 125) + A/Bethesda/1/85 (H3N2, CR90) + B/Ann Arbor/1/86 (B, CRB117)
Outcomes	Mild upper respiratory symptoms. Fever >= 37.8 °C within 1 week after each inoculation
Notes	Safety data only were extracted Government 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