Trial Outcomes & Findings for Human Challenge Model Refinement With Enterotoxigenic Escherichia Coli Strain B7A (NCT NCT02773446)

Last Updated: 2018-07-06

Results Overview

Solicited symptoms (vomiting, abdominal pain, bloating, lightheadedness, anorexia, generalized myalgia, arthralgias, abdominal cramping, constipation, nausea, malaise, headache, flatulence)

Recruitment status

COMPLETED

Study phase

Target enrollment

47 participants

Primary outcome timeframe

6 days post-challenge

Results posted on

2018-07-06

Participant Flow

Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47.

Participant milestones

Participant milestones
Measure	Cohort 1 Group A Volunteers will receive 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B Volunteers will receive 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C Volunteers will receive 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D Volunteers will receive 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A subjects from Cohort 1 who met primary endpoint will receive optimal regimen as determined by analysis after Cohort 1. ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B Naive subjects who will receive optimal regimen as determined by analysis after Cohort 1 ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
First Admission STARTED	7	7	7	7	0	0
First Admission COMPLETED	6	7	7	6	0	0
First Admission NOT COMPLETED	1	0	0	1	0	0
Second Admission STARTED	0	0	0	0	11	19
Second Admission COMPLETED	0	0	0	0	11	19
Second Admission NOT COMPLETED	0	0	0	0	0	0

Reasons for withdrawal

Reasons for withdrawal
Measure	Cohort 1 Group A Volunteers will receive 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B Volunteers will receive 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C Volunteers will receive 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D Volunteers will receive 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A subjects from Cohort 1 who met primary endpoint will receive optimal regimen as determined by analysis after Cohort 1. ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B Naive subjects who will receive optimal regimen as determined by analysis after Cohort 1 ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
First Admission Withdrawal by Subject	0	0	0	1	0	0
First Admission Lost to Follow-up	1	0	0	0	0	0

Baseline Characteristics

Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Cohort 1 Group A n=7 Participants 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B n=7 Participants 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C n=7 Participants 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D n=7 Participants 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A n=11 Participants subjects from Cohort 1 who met primary endpoint - 9 logs of E.coli strain B7A ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B n=19 Participants Naive subjects - 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Total n=58 Participants Total of all reporting groups
Age, Continuous Cohort 1	36 years n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	34 years n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	39 years n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	35 years n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	—	—	34.5 years n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Age, Continuous Cohort 2	—	—	—	—	39 years n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	35 years n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	36 years n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Sex: Female, Male Cohort 1 · Female	2 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	3 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	2 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	8 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Sex: Female, Male Cohort 1 · Male	5 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	4 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	5 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	6 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	20 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Sex: Female, Male Cohort 2 · Female	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	3 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	5 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	8 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Sex: Female, Male Cohort 2 · Male	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	8 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	14 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	22 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Ethnicity (NIH/OMB) Cohort 1 · Hispanic or Latino	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Ethnicity (NIH/OMB) Cohort 1 · Not Hispanic or Latino	7 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	6 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	7 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	7 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	27 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Ethnicity (NIH/OMB) Cohort 1 · Unknown or Not Reported	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Ethnicity (NIH/OMB) Cohort 2 · Hispanic or Latino	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	5 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	5 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Ethnicity (NIH/OMB) Cohort 2 · Not Hispanic or Latino	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	11 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	14 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	25 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Ethnicity (NIH/OMB) Cohort 2 · Unknown or Not Reported	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · American Indian or Alaska Native	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · Asian	1 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · Native Hawaiian or Other Pacific Islander	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · Black or African American	5 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	6 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	7 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	6 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	24 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · White	1 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	3 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · More than one race	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 1 · Unknown or Not Reported	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=7 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=28 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · American Indian or Alaska Native	—	—	—	—	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · Asian	—	—	—	—	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	1 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · Native Hawaiian or Other Pacific Islander	—	—	—	—	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · Black or African American	—	—	—	—	11 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	13 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	24 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · White	—	—	—	—	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	2 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	2 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · More than one race	—	—	—	—	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	0 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Race (NIH/OMB) Cohort 2 · Unknown or Not Reported	—	—	—	—	0 Participants n=11 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	3 Participants n=19 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.	3 Participants n=30 Participants • Cohort 2 group A consists of 11 subjects from Cohort 1. These subjects were re admitted for a second admission. The total number of subjects enrolled was 47. Each cohort was analyzed separately.
Region of Enrollment United States · Cohort 1	7 Participants n=7 Participants	7 Participants n=7 Participants	7 Participants n=7 Participants	7 Participants n=7 Participants	0 Participants n=11 Participants	0 Participants n=19 Participants	28 Participants n=58 Participants
Region of Enrollment United States · Cohort 2	0 Participants n=7 Participants	0 Participants n=7 Participants	0 Participants n=7 Participants	0 Participants n=7 Participants	11 Participants n=11 Participants	19 Participants n=19 Participants	30 Participants n=58 Participants

PRIMARY outcome

Timeframe: 6 days post-challenge

Solicited symptoms (vomiting, abdominal pain, bloating, lightheadedness, anorexia, generalized myalgia, arthralgias, abdominal cramping, constipation, nausea, malaise, headache, flatulence)

Outcome measures

Outcome measures
Measure	Cohort 1 Group A n=7 Participants 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B n=7 Participants 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C n=7 Participants 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D n=7 Participants 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A n=11 Participants subjects from Cohort 1 who met primary endpoint 9 logs of E.coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B n=19 Participants Naive subjects - 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Vomiting	0 Participants	0 Participants	3 Participants	2 Participants	1 Participants	3 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Abdominal Pain	3 Participants	4 Participants	5 Participants	4 Participants	7 Participants	12 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Bloating	5 Participants	6 Participants	5 Participants	4 Participants	5 Participants	11 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Lightheadedness	1 Participants	4 Participants	4 Participants	1 Participants	2 Participants	3 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Anorexia	4 Participants	4 Participants	5 Participants	4 Participants	4 Participants	14 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Generalized Myalgia	0 Participants	1 Participants	0 Participants	1 Participants	2 Participants	3 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Arthralgias	0 Participants	1 Participants	0 Participants	1 Participants	1 Participants	3 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Abdominal Cramping	5 Participants	5 Participants	5 Participants	3 Participants	7 Participants	13 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Constipation	1 Participants	1 Participants	2 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Nausea	3 Participants	3 Participants	4 Participants	3 Participants	3 Participants	8 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Malaise	4 Participants	4 Participants	4 Participants	3 Participants	4 Participants	10 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Headache	3 Participants	4 Participants	4 Participants	5 Participants	4 Participants	10 Participants
Number of Participants With Safety- Solicited Symptoms Related to Challenge Administration Flatulence	7 Participants	6 Participants	6 Participants	4 Participants	7 Participants	10 Participants

PRIMARY outcome

Timeframe: 5 days post challenge (Cohort 1 and Cohort 2 group B) 7 days post challenge (Cohort 2 Group A)

Moderate-severe diarrhea post challenge defined as * moderate diarrhea: 4 to 5 loose/liquid stools or 401-800 of loose/liquid stool in any 24-hour period * Severe diarrhea greater than or equal to 6 loose/liquid stools or greater than 800 g of loose/liquid stools in any 24-hour period

Outcome measures

Outcome measures
Measure	Cohort 1 Group A n=7 Participants 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B n=7 Participants 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C n=7 Participants 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D n=7 Participants 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A n=11 Participants subjects from Cohort 1 who met primary endpoint 9 logs of E.coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B n=19 Participants Naive subjects - 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
Moderate-severe Diarrhea	3 Participants	3 Participants	5 Participants	5 Participants	5 Participants	11 Participants

PRIMARY outcome

Timeframe: 7 days post-challenge

Moderate-severe diarrhea post-challenge defined as * Moderate diarrhea: 4 to 5 loose/liquid stools or 401-800g of loose/liquid stool in any 24- hour period * Severe diarrhea: greater than or equal to 6 loose/liquid stools or greater than 800 g of loose/liquid stool in any 24-hour period

Outcome measures

Outcome measures
Measure	Cohort 1 Group A n=11 Participants 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A subjects from Cohort 1 who met primary endpoint 9 logs of E.coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B Naive subjects - 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
Moderate-severe Diarrhea in Subjects Receiving Homologous Rechallenge	5 Participants	—	—	—	—	—

PRIMARY outcome

Timeframe: 6 days post-challenge

Safety solicited symptoms unrelated to challenge administration (vomiting, abdominal pain, bloating, lightheadedness, anorexia, generalized myalgia, arthralgias, abdominal cramping, constipation, nausea, malaise, headache, flatulence)

Outcome measures

Outcome measures
Measure	Cohort 1 Group A n=7 Participants 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B n=7 Participants 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C n=7 Participants 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D n=7 Participants 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A n=11 Participants subjects from Cohort 1 who met primary endpoint 9 logs of E.coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B n=19 Participants Naive subjects - 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Generalized myalgia	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Arthralgias	0 Participants	0 Participants	0 Participants	0 Participants	1 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Vomiting	1 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Abdominal pain	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Bloating	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Lightheadedness	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Anorexia	1 Participants	1 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Abdominal Cramping	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Constipation	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Nausea	1 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Malaise	1 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Headache	1 Participants	1 Participants	1 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Safety -Solicited Symptoms Unrelated to Challenge Administration Flatulence	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants	0 Participants

SECONDARY outcome

Timeframe: 28 days post challenge

Outcome measures

Outcome measures
Measure	Cohort 1 Group A n=7 Participants 8 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group B n=7 Participants 9 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group C n=7 Participants 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 1 Group D n=7 Participants 10 logs of E. coli strain B7A after 90 minute fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group A n=11 Participants subjects from Cohort 1 who met primary endpoint 9 logs of E.coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria	Cohort 2 Group B n=19 Participants Naive subjects - 9 logs of E. coli strain B7A after overnight fast ETEC strain B7A (O148:H28 CS6+ LT+ST+) (Lot 0481) in Buffer: ETEC Bacteria
Immune Response to Challenge (Serology) IgA LPS	5 Participants	6 Participants	4 Participants	7 Participants	6 Participants	18 Participants
Immune Response to Challenge (Serology) IgG C66	1 Participants	3 Participants	0 Participants	0 Participants	3 Participants	4 Participants
Immune Response to Challenge (Serology) IgG LT	2 Participants	1 Participants	3 Participants	4 Participants	6 Participants	10 Participants
Immune Response to Challenge (Serology) IgG LPS	2 Participants	2 Participants	1 Participants	4 Participants	4 Participants	7 Participants
Immune Response to Challenge (Serology) IgA CS6	1 Participants	1 Participants	2 Participants	0 Participants	1 Participants	2 Participants
Immune Response to Challenge (Serology) IgA LT	1 Participants	0 Participants	2 Participants	1 Participants	4 Participants	3 Participants

SECONDARY outcome

Timeframe: 6 days post challenge

Population: samples for ALS IgG and IgA were unavailable for 1 participant in cohort 2 group A Samples for ALS IgG CS6, LT and IgA CS6 were unavailable for 1 participant in cohort 2 group B

Antibody in Lymphocyte Supernatant (ALS) Immunoglobin G (IgG) (CS6) coli surface antigen 6 Immunoglobin G (IgG) heat labile Toxin (LT) Immunoglobin G (IgG) (LPS) Lipopolysaccharide Immunoglobin A (IgA) (CS6) coli surface antigen 6 Immunoglobin A (IgA) heat labile Toxin (LT) Immunoglobin A (IgG) (LPS) Lipopolysaccharide