Immunogenicity of One Versus Two Doses of Killed Oral Cholera Vaccine

• Geometric mean serum vibriocidal titers compared to baseline [ Time Frame: 14 days after each dose ] [ Designated as safety issue: No ]
• Proportion of subjects with any of the following adverse events: immediate reactions within 30 minutes after each dose and up to 3 days after each dose and serious adverse events occurring throughout the trial. [ Time Frame: after dosing: 30 minutes to 3 days for adverse events, 28 days for serious adverse events ] [ Designated as safety issue: Yes ]

• Geometric mean serum vibriocidal titers at baseline and 14 days after dose 1 and 14 days after dose 2.
• Proportion of subjects with any of the following adverse events: immediate reactions within 30 minutes after each dose and up to 3 days after each dose and serious adverse events occurring throughout the trial.

The purpose of this study is to compare the safety and immunogenicity of one and two doses of the killed oral cholera vaccine.

Cholera is an important public health problem worldwide, particularly in endemic areas of the developing world. In 2004, 101 383 cholera cases and 2345 deaths were reported to the WHO. Provision of safe water and food, adequate sanitation and improved personal and community hygiene are the main public health interventions against cholera. These measures cannot be implemented in the near future in the most cholera-endemic areas.

Phase II trials of this reformulated killed oral cholera vaccine were performed in SonLa, Vietnam and Kolkata, India. Significant vibriocidal antibody responses were observed among vaccine recipients.

Distribution of 2 doses of the cholera vaccine is often difficult in field settings and limits its utility in emergency situations, since an interval of 2 weeks is usually required between doses. Recent data from Vietnam suggests that greater vibriocidal responses following 2 doses are elicited compared to previous formulations. Furthermore, in a study in Bangladesh comparing immune responses to the vaccine among children supplemented with vitamin A and zinc, seroconversion after the first dose was robust in all groups suggesting that one dose may be used in the control of cholera.

Data regarding the immune response following one dose of this reformulated vaccine is currently unavailable. If a single dose of this vaccine is confirmed to be immunogenic to recipients, then this vaccine may be used more extensively for public health purposes, especially during times of outbreaks.

The objective of this study is to confirm the safety of the killed oral cholera vaccine among adult and children volunteers.

• Cholera
• Diarrhea
• Vibrio Infections

• Biological: Killed bivalent whole cell oral cholera vaccine

  Each 1.5 mL dose, given orally, contains:

  V. cholerae O1 Inaba El Tor strain Phil 6973 formalin killed, 600 Elisa units (EU) LPS V. cholerae O1 Ogawa classical strain Cairo 50 heat killed 300 EU LPS V. cholerae O1 Ogawa classical strain Cairo 50 formalin killed 300 EU LPS V. cholerae O1 Inaba classical strain Cairo 48 heat killed 300 EU LPS V. cholerae O139 strain 4260B formalin killed 600 EU LPS

• Biological: Heat Killed E. coli Placebo
  Heat Killed E.coli in an optical turbidity identical to cholera vaccine, given in a 1.5 mL oral dose.

• Experimental: 1
  Cholera Vaccine
  Intervention: Biological: Killed bivalent whole cell oral cholera vaccine
• Placebo Comparator: 2
  Placebo
  Intervention: Biological: Heat Killed E. coli Placebo

Inclusion Criteria:

• Healthy adult male and non-pregnant female adults aged 18-40 years and healthy children aged 1-17 years

All subjects must satisfy the following criteria at study entry:

• Male or female adult residents aged 18-40 years or children aged 1- 17 years who the investigator believes will comply with the requirements of the protocol (i.e. available for follow-up visits and specimen collection)
• For females of reproductive age, they must not be pregnant (as determined by verbal screening)
• Written informed consent obtained from subjects or their guardians, and written assent for children aged 12-17 years.
• Healthy subjects as determined by: medical history, physical examination, clinical judgement of the investigator.

Exclusion Criteria:

• Ongoing serious chronic disease
• Immunocompromising condition or therapy
• Diarrhea (3 or more loose stools within a 24-hour period) 6 weeks prior to enrollment
• one or two episodes of diarrhea lasting for more than 2 weeks in the past 6 months
• one or two episodes of abdominal pain lasting for more than 2 weeks in the past 6 months
• intake of any anti-diarrhoeal medicine in the past week
• abdominal pain or cramps, loss of appetite, nausea, general ill-feeling or vomiting in the past 24 hours
• acute disease one week prior to enrollment, with or without fever. Temperature > or = 38 degrees C (oral) or axillary temperature > or = 37.5 degrees C warrants deferral of the vaccination pending recovery of the subject
• receipt of antibiotics in past 14 days
• receipt of live or killed enteric vaccine in last month
• receipt of killed oral cholear vaccine

• National Institute of Cholera and Enteric Diseases, India
• Shantha Biotechnics Limited