Clinical Research Directory

Vaccine- and Infection-derived Correlates of Protection for Cholera

Background: Vibrio cholerae causes millions of cholera cases and thousands of deaths annually. Vaccines are in short supply. There is no agreement on how to introduce new vaccines or evaluate their effectiveness, and the lack of 'correlates of protection' (CoPs) against cholera is a major obstacle to vaccine development. CoPs are markers of effective immune response to vaccination. While other infectious diseases have well established CoPs, none are widely accepted for cholera. Relevance: Lack of accepted CoPs impedes development of cholera vaccines, limiting progress toward improved vaccines, slowing the licensure of new vaccines, and contributing to the current vaccine shortage; an immediate obstacle to achieving reductions in cholera-related illness and deaths. The identification of new CoPs will speed the development of improved cholera vaccines and provide a pathway to their licensure and use. Hypothesis: The investigators hypothesize that some individuals who receive inactivated oral cholera vaccine (OCV) will develop antibody responses which predict protection against V. cholerae infection and that specific immune responses distinguish individuals who are protected against cholera by prior natural infection from those who are protected from OCVs. Objectives: The investigators will administer an OCV or typhoid vaccine (TCV) control and monitor antibody responses to identify better CoPs for cholera following both vaccination and natural infection. Methods: The investigators will randomize 1219 participants; 554 participants will receive an inactivated bivalent OCV, 665 participants will receive a TCV control. The investigators will collect 12 blood samples over two-years following vaccination to measure antibodies against V. cholerae and to monitor for re-infection. Outcome measures/variables: The endpoint of interest is V. cholerae infection after vaccination. The investigators define infection as positive culture or PCR for V. cholerae or seroconversion events observed over the 2-year follow up period.

Preventative Intervention for Cholera for 7 Days

The first objective of our study is to develop a theory-driven evidence-based targeted water, sanitation, and hygiene (WASH) intervention for household members of diarrhea patients in South Kivu, Democratic Republic of the Congo (DRC) through formative research and community engagement. The second objective is to conduct a randomized controlled trial of 2,320 household members of 580 severe diarrhea patients to evaluate the effectiveness of the developed targeted WASH intervention in terms of: 1. reducing diarrheal diseases household members of cholera and severe diarrhea patients; and 2. increasing WASH behaviors.

Cholera-Hospital-Based-Intervention-for-7-Days (CHoBI7) Water, Sanitation, and Hygiene (WASH) Case Area Targeted Intervention (CATI)

Objective: The investigators objective is to develop and evaluate the effectiveness of a case area targeted water, sanitation, and hygiene (WASH) intervention in reducing cholera infections and increasing sustained WASH behaviors in transmission hotspots in a ring around cholera cases.

Single Dose Azithromycin to Prevent Cholera in Children

This study aims to determine whether single-dose azithromycin is effective in preventing cholera in children who are at extremely high risk of infection. The study will also determine the effect of this intervention on the development of antibiotic resistant bacteria. The results will inform future strategies to prevent cholera in children, and improve overall understanding of the impact of azithromycin on antibiotic resistance.

Testing a Scalable Model of the Cholera Hospital-Based Intervention for 7 Days (CHoBI7)

The findings from previous recent randomized controlled trials of The Cholera Hospital Based Intervention for 7 Days (CHoBI7) demonstrated that this intervention was effective in significantly reducing symptomatic cholera infections, diarrheal disease, and stunting among young children in intervention households, and had significant sustained impacts on handwashing with soap behaviors and improved water quality 12 months post intervention. Therefore, the investigators next step in the transition to scale is to: (1) To tailor the CHoBI7 program for delivery in rural health facilities and market test the CHoBI7 Program to determine the feasibility of providing a modified water, sanitation, and hygiene (WASH) package with only a soapy water bottle and chlorine tablets in both urban and rural settings through formative research and engagement of key stakeholders (Formative Research Phase); and (2) To evaluate the effectiveness of delivering the CHoBI7 program in district hospitals and sub-district health complexes in rural areas in terms of increases in WASH behaviors and decreases in diarrheal disease by conducting a randomized controlled trial (RCT) (Intervention Implementation and Evaluation Phase).

Impact Study of Cholera Vaccination in Endemic Areas - Clinical Surveillance

This project aims to fill this essential knowledge gap by assessing the impact of oral cholera vaccine mass campaigns in 2 sites (urban and rural) in DRC, described in this protocol. The evidence generated from this project will be key to develop future strategies regarding cholera vaccine use in endemic settings, including places with higher burden in terms of cholera mortality.