Sanchez 1994 Peru.

Study characteristics
Methods	Design: Randomized controlled trial (individual block randomization in groups of 10) Duration: Enrolled January to March 1994, follow‐up to June 1994 Surveillance: Passive surveillance through clinics within the military training centres where the study was conducted
Participants	Sample size: 1563 enrolled, 1426 received 2 doses of vaccine or placebo Inclusion criteria: 17‐65 years volunteers, available for three months Exclusion criteria: Previous cholera vaccination
Interventions	Vaccine: Killed whole‐cell vaccine plus recombinant cholera toxin subunit (WC‐rBS; Dukoral®, SBL, Sweden) Placebo: Heat ‐inactivated E. coli K12 strain Vaccine and placebo were given with freshly prepared antacid solution. Two doses were given, 7 to 14 days apart.
Outcomes	Included in the review: Cases of confirmed cholera Not included in the review: Cases of severe cholera (cholera with signs of dehydration) as the treatment group is not stated Cases subgrouped by blood group as the treatment group is not stated
Notes	Location: Lima, Peru Setting: Military training centres Source of funding: Not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was done in blocks of 10 to ensure equal study groups" Comment: Unclear description but probably done
Allocation concealment (selection bias)	Low risk	Quote: "Each bottle was identified with a unique code number; vaccine and placebo bottles were pre‐coded"
Blinding (performance bias and detection bias) Efficacy outcomes	Low risk	Quote: "The placebo....in a concentration identical in turbidity and appearance to the vaccine preparation" Plus see above
Blinding (performance bias and detection bias) Safety outcomes	Unclear risk	Not applicable as safety data is not reported
Incomplete outcome data (attrition bias) Efficacy outcomes	High risk	Comment: Subjects lost to follow‐up after the second dose were assumed to contribute half the period to the denominator analysis. Mentioned that losses to follow‐up were similar in both groups. Cases of cholera which occurred in participants between study doses were excluded from the primary analysis.
Incomplete outcome data (attrition bias) Safety outcomes	Unclear risk	Not applicable as safety data is not reported
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting
Other bias	Low risk	No evidence of other bias