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. 2018 Feb 1;2018(2):CD004879. doi: 10.1002/14651858.CD004879.pub5

ab King 1998.

Methods Randomised, placebo‐controlled, multicentre trial
Participants Children aged 18 to 71 months in good health. 238 were enrolled altogether at Baylor College of Medicine Houston, Cincinnati Children Hospital, Saint Louis University, and University of Maryland at Baltimore in 3 steps. 118 were enrolled from 1 ambulatory clinic in the northern area of Santiago (Chile).
Interventions Cold‐adapted trivalent flu vaccine containing the strains A/Johannesburg/33/94 (H3N2), B/Panama/45/90, and A/Texas/36/91 (H1N1) in different titre (104, 105, 106, or 107 TCID50 of each strain) versus placebo.
Vaccine and placebo (allantoic fluid) were assigned in double‐blind manner using a randomisation table provided by the manufacturer (Avion). Enrolment took place in 3 steps:

  • 115 children in the USA and 60 in Chile were randomised to receive either 104 or 105 TCID50 of vaccine or placebo at a ratio of 1:1:1.

  • 59 children in the USA and 30 in Chile were randomised to receive 106 TCID50 of vaccine or placebo at 2:1 ratio.

  • 64 children in the USA and 28 in Chile were randomised to 107 TCID50 of vaccine or placebo in a 2:1 ratio.


In the USA the randomisation was designed so that 50% of the children received vaccine or placebo as drops and the remaining 50% by spray.
Outcomes Serological
 Antibody titres
Effectiveness
 N/A
Safety
 Temperature was recorded each evening within 10 days after vaccination on a diary card. Other daily recorded symptoms were: cough, wheezing, rhinorrhoea, sore throat, or irritability. Children were examined by clinicians if an axillary, oral, or rectal temperature > 38 °C was observed.
Funding Source Government/industry
Notes The authors conclude that the vaccine was safe and immunogenic in 2 of the 3 strains. Small denominator
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Unclear risk Insufficient description
Allocation concealment (selection bias) Unclear risk No description
Blinding (performance bias and detection bias) 
 All outcomes Unclear risk Insufficient description
Incomplete outcome data (attrition bias) 
 All outcomes Low risk No losses to follow‐up
Summary assessments Unclear risk Insufficient information about study design