aa Mcbride 2016b.

Methods	Randomised placebo‐controllled trial
Participants	Healthy adults aged 18 to 64
Interventions	Trivalent influenza inactivated vaccines containing antigens the 2 A strains and 1 B strain recommended by WHO in 2008 and 2009 for the Southern Hemisphere as follows: Arm 1: 15 mg of haemagglutinin antigens A/Brisbane/59/2007 (H1N1), A/Brisbane/10/2007 (H3N2), B/Florida/4/2006. Fluvax; CSL Limited. 0.5 mL single doses administered intramuscularly into deltoid muscle. Placebo: 0.5 mL saline, dibasic sodium phosphate and monobasic sodium phosphate.
Outcomes	Influenza cases laboratory‐confirmed by viral culture and/or real time RT‐PCR were followed up until 30 November each year. Solicited adverse events for 4 days, unsolicited adverse events for 20 days, serious adverse events for 180 days. Harms data were not extractable due to different definitions.
Notes	This record is for the 2009 season. Industry funded
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“Participants were randomized in a 2:1 ratio to receive a single injection of 0.5 mL IIV3 or placebo, administered intramuscularly into the deltoid muscle.” “The randomization code was prepared by a statistician, employed by CSL Limited, with the use of SAS software (version 9.1.3; SAS Institute, Cary, NC, USA ...”
Allocation concealment (selection bias)	Low risk	“The randomization code was prepared by a statistician, employed by CSL Limited, with the use of SAS software (version 9.1.3; SAS Institute, Cary, NC, USA), using simple block randomization to maintain approximate allocation balance.”
Blinding (performance bias and detection bias) All outcomes	Unclear risk	“As there was a visual difference between IIV3 and placebo, study personnel who were involved in the preparation and administration of the study vaccine had no further involvement in the study conduct. Participants and investigational site staff involved in performing study assessments remained blinded to treatment allocation.”
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Flow of participants is reported and described. Attrition was 2.52% and 1.6% for the intervention and placebo arms, respectively. In this season (2009) 104/5001 and 40/2499 received H1N1 pandemic vaccine, respectively in the 2 arms and were excluded from efficacy assessment.
Summary assessment	Low risk