ab Belshe 1992

Methods	RCT of safety vaccine, double‐blind 0.5 ml of trivalent vaccine administered intranasally (as previously described, see notes for refs) Children observed in own homes for 11 days by nursing staff Daily sampling ‐ nasopharyngeal swabbing for isolation of influenza virus Serum for antibody determination obtained on days 0 and 28 to 31
Participants	Healthy children age 6 months to 13 years
Interventions	Live, trivalent vaccine, recombinant containing A/Kawasaki/9/86 (H1N1) CR125 + A/Korea/1/82 CR59 + B/Texas/1/84 CRB‐87 A/Kawasaki/9/86 and A/Korea/1/82 derived from cold‐adapted A/Ann/Arbor/6/60 parent virus B/Texas/1/84 derived from cold‐adapted B/Ann Arbor/1/66 parent virus
Outcomes	Adverse reactions up to 11 days after vaccination Fever: rectal temperature > 38.3°C (infants and young children); oral temperature > 37.8°C in older children) Upper respiratory illness: rhinorrhoea on 2 consecutive days; lower respiratory illness; wheeze or pneumonia; OM Viral shedding (data not extracted) Serologic response to vaccine (data not extracted)
Funding Source	Government
Notes	Safety data presented separately for seronegative and seropositive responders but has been combined for extraction. Was significantly (P < 0.5) higher upper respiratory illness in seronegative individuals than seropositive individuals
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	High risk	Not used
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk
Summary assessments	High risk	Lack of allocation concealment; plausible bias that seriously weakens confidence in the results.