Please select the eligibility criteria that correspond to the clinical trial below.
Title: Effect of Extended Dose Intervals on the Immune Response to Oral Cholera Vaccine
Brief Summary: Cholera is a life-threatening disease if prompt actions are not taken. The most recent estimates of the global burden of cholera estimate that there are more than 1.3 billion people at risk. Of which, 2.86 million (range: 1.3-4.0 million) will contract cholera and 95,000 (21,000-143,000) will die each year. A safe, effective, and affordable killed whole-cell oral cholera vaccine (OCV) is now being used widely to prevent cholera in areas at risk. This regimen demonstrated 65% efficacy retained for at least 3 years and even up to 5 years in an endemic setting.

The primary aim of this project is to determine changes in the vibriocidal geometric mean titers (GMT) in subjects who receive the second dose of oral cholera vaccine (OCV) at different intervals: 2 weeks, or 6 months following the first dose of vaccine. Secondary aims include a) vibriocidal antibody response rates in subjects who receive OCV at 2 weeks or 6 months following the first dose of vaccine, b) age specific serum vibriocidal GMTs following the second dose among participants given the second dose of OCV at intervals of 2 weeks or 6 months following the first dose of vaccine, c) GMT and antibody response rates of Immunoglobulin A (IgA) and Immunoglobulin G (IgG) anti-lipopolysaccharide (anti-LPS) as measured by ELISA following the second dose among participants given the second dose of OCV at intervals of 2 weeks or 6 months following the first dose of vaccine. Our hypothesis is that the vibriocidal GMT following the second dose, when given after 6 months will not be inferior to the response when the second dose is given according to the standard interval of two weeks.


Options:
A: Inclusion Criteria:

* Healthy non-pregnant adults aged 18-40 years and children aged 1-17 years

Exclusion Criteria:

* Diarrhea during the past week
* Antibiotic and anti-diarrheal medicine use during the past week
* One or more episodes of diarrhea or abdominal pain lasting for 2 weeks during the past 6 months
* Abdominal pain, nausea, vomiting, loss of appetite or generalized ill feeling for the past 24 hours
* Pregnancy
B: Inclusion Criteria:

* Healthy residents of selected vaccination sites
* Aged 2 years and older
* non-pregnant

Exclusion Criteria:

* Age less than 2 years
* Pregnant
C: Inclusion Criteria:

Healthy subjects \> 1 year of age and above Living in high risk area for cholera Provision of Informed consent for participating in the study by participant /parent or guardian as well as verbal assent for children 11-17 years.

Exclusion Criteria:

Pregnant women Aged less than 1 year History of taking cholera vaccine
D: Inclusion Criteria:

1. Age ≥1 year, stratified into different age groups
2. Living in the Waya Clinic Catchment Area
3. Good health condition, without clinically significant medical history (by participant or guardian, in case of minor)
4. Not pregnant for female subjects.
5. Available to participate for the study duration, including all planned follow-up visits for up to 9 months from screening.
6. Signed informed consent

Exclusion Criteria:

1. Presence of a significant medical or psychiatric condition (Examples include: Diagnosis and treatment of tuberculosis (TB) or HIV; renal insufficiency; hepatic disease; oral or parenteral medication known to affect the immune function, such as corticosteroids, other immunosuppressant drugs; or behavioural or memory issues)
2. Ever having received oral cholera vaccine.
3. Receipt of an investigational product (within 30 days before vaccination).
4. History of diarrhoea in 7 days prior to first dose of vaccine (defined as ≥3 unformed loose stools in 24 hours).
5. History of chronic diarrhea (lasting for more than 2 weeks in the past 6 months)
6. Current use of laxatives, antacids, or other agents to lower stomach acidity?
7. Planning to become pregnant in the next 2 years.

Answer: D