Gotuzzo 1993.

Study characteristics
Methods	Design: A randomized controlled trial (individually randomized) Duration: Vaccination from Sept to Dec 1991; follow‐up 28 days
Participants	Sample size: 241 enrolled Inclusion criteria: Adults aged 18 to 38 years Exclusion criteria: Pregnancy, antibiotics or diarrhoea within the previous 72 h, previous cholera vaccine.
Interventions	Vaccine 1: CVD 103‐HgR live attenuated vaccine containing: 5 x 109 lyophilized organisms of a genetically modified V. cholerae O1 Vaccine 2: CVD 103‐HgR live attenuated vaccine containing: 5 x 108 lyophilized organisms of a genetically modified V. cholerae O1 Placebo: 5 x 108 cells of heat‐killed E. coli K‐12 strain
Outcomes	Included in review: Adverse events during the first 7 days Not included in the review: Immunological outcomes: Geometric mean rise in vibriocidal antibody titres, and proportion who develop ≥4 fold rises in serum titres from baseline after one or two doses
Notes	Location: Peru Setting: 2 groups: high socioeconomic group: medical students and physicians from the Facultad de Medicina, Universidad Peruana Cayetano Heredia, and a low socioeconomic group: selected from Canto Grande, a periurban slum community with poor water and sanitation. Source of funding: National Institute of Allergy and Infectious Diseases (NIAID)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: Described as 'randomized', no further details given.
Allocation concealment (selection bias)	Low risk	Quote: 'Eligible adults were administered coded preparations sequentially labelled A, B, or C, two of which contained the vaccine and the other a placebo'.
Blinding (performance bias and detection bias) Efficacy outcomes	Unclear risk	Not applicable as efficacy not reported
Blinding (performance bias and detection bias) Safety outcomes	Low risk	Quote: 'Double‐blind clinical follow‐up was maintained for 7 days following vaccination'.
Incomplete outcome data (attrition bias) Efficacy outcomes	Unclear risk	Not applicable as efficacy not reported
Incomplete outcome data (attrition bias) Safety outcomes	Low risk	Comment: No losses to follow up are reported
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting
Other bias	Low risk	No evidence of other bias