Effectiveness of a Bivalent Killed Whole Cell Based Oral Cholera Vaccine
Various field studies has found that the modified , bivalent, whole cell - based oral cholera vaccine (OCV) to be safe, immunogenic and effective with protective efficacy of 67 % in earlier clinical trials. However, the effectiveness of the vaccine in "real" life situation using the public health system is unknown. It is critical to follow up in the same population, where pilot introduction of OCV was introduced and evaluate vaccine proactive effectiveness at individual as well as at population level. The follow - up and determination of effectiveness of mass OCV vaccination was requested by State Government.
|Study Design:||Observational Model: Case Control
Time Perspective: Prospective
|Official Title:||Effectiveness of a Bivalent, Killed Whole-cell Based Oral Cholera Vaccine(Shanchol®) Delivered Through Community-based Mass Vaccination Campaign in a High-risk Population in India: Matched Case-control Studies|
- Vaccine protective effectiveness at individual level [ Time Frame: 6 months ] [ Designated as safety issue: No ]Matched controls will be selected among the persons of the same age group, gender, and residence as that of each case. 1 to 4 ratio will be used in matching cases to controls.Information on all other exposure variables will be collected through an inperson interview with cases and controls. "Protective effectiveness (PE) (%) = [1- the odds of vaccination among cholera confirmed cases relative to the odds of vaccination among matched controls] × 100" is the metric to measure vaccine protective effectiveness at individual level.
- Population level effectiveness (herd effect) [ Time Frame: 6 months ] [ Designated as safety issue: No ]
Indirect effect: Fraction of household members who are vaccinated in households of unvaccinated cases compared with fraction of household members who are vaccinated in households of unvaccinated controls
Total effect: Fraction of household members who are vaccinated in households of vaccinated cases compared with the fraction of household members who are vaccinated in households of vaccinated controls.
Overall effects: Fraction of household members who are vaccinated in household of cases compared with fraction of household members who are vaccinated in control households.
- Cohort / GIS study for the measure of herd protection [ Time Frame: 6 months ] [ Designated as safety issue: No ]Geographic unit as a cluster for evaluating vaccine herd protection with the use of cohort analysis, using GIS information from the baseline census. Here, there will be comparison in the incidence of the target outcome (cholera or non-cholera diarrhea) according to the level of vaccine coverage of the geographic unit.
Biospecimen Retention: Samples Without DNA
Rectal swabs will be collected from all cases and control that fulfills inclusion criteria. It will be plated directly into TCBS agar as well as after enrichment in APW for 6 to 20 hours (pH 8.6, 37 degree centrigrade). After this overnight incubation, suspected colonies from TCBS will be tested biochemically and agglutinated with polyvalent, Ogawa and Inaba antisera. Biotyping of O1 isolates will be done with chicken erythrocyte agglunitation tests and determination of polymyxin sensitivity. Non - agglunating strains will be tested with antiserum to V cholarae O139 strain. V cholarae isolates will be tested for susceptibility to the following antimicrobials: tetracycline, erythromycin, furazolidin, trimithprim - sulfame thoxale, ciprofloxacin and norfloxacin.
|Study Start Date:||January 2013|
|Estimated Study Completion Date:||June 2014|
|Estimated Primary Completion Date:||November 2013 (Final data collection date for primary outcome measure)|
cholera cases group
It is defined as "Any diarrheal cases or suspected cholera cases from study area, whose stool specimen collected in study health center and examined in reference laboratory, reveals V. cholerae serotype O1/O139 is cholera case".
It is defined as,"A randomly selected age, sex and village/hamlet matched individuals, who have been living in the study area and did not seek care for diarrheal illness in the study health center since vaccination."
The overall goal of this study is to evaluate the protective effectiveness of one or two doses of modified, bivalent, killed whole cell based OCV, given at least 14 days apart, when delivered through community - based mass vaccination campaign using existing public health infrastructure in a high - risk population in Satyabadi block of Puri district, Orissa, India.
This study has following objectives
* To evaluate the individual level protective effectiveness of one or two doses of OCV against culture confirmed cholera episodes, severe enough to seek a formal health care.
- To evaluate population - level effectiveness (herd effects)of OCV delivered through a community based mass vaccination when the vaccine is delivered to more than half of population at risk.
- To determine inverse correlation between vaccine coverage and cholera incidence among diverse geographical clusters.
|Contact: Binod Sah, MBBS, MS||+822 - 8811 firstname.lastname@example.org|
|Regional Medical Research Center||Not yet recruiting|
|Chandrashekharpur, Bhubaneswar, Orissa, India, 751016|
|Contact: Shantanu K Kar, MD 91-674-301322 email@example.com|
|Contact: Anna S Kerketta, MBBS 91-674-2301387 firstname.lastname@example.org|
|Principal Investigator:||Shantanu K Kar, MD||Director, Regional Medical Research Center, Bhubanewar, Orissa, India|
|Principal Investigator:||Sunheang Shin, PHD||International Vaccine Institute|