View clinical trials related to Cholera.
Filter by: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: We 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: We 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: We will randomize 1219 individuals; 554 will receive an inactivated bivalent OCV, 665 will receive a TCV control. We 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. We define infection as positive culture or PCR for V. cholerae or seroconversion events observed over the 2-year follow up period.
An open-label, randomized controlled, non-inferiority study of co-administration of OCV, TCV and MR vaccines among children 12 to 59 months of age in Dhaka, Bangladesh will be conducted. Children who did not receive any of the aforementioned vaccines will be included in the study. This study will be conducted among 2117 children of 12-59 months of age residing in Mirpur area (wards 4, and 6-16) of Dhaka north and Kamrangirchar, Hazaribag and Rayerbazar areas (wards 14, 22, 56, 57, and 58) of Dhaka south to enroll the required number of participants. Only children who have not previously received the vaccines will be enrolled. The findings of this study are likely to have a significant impact on vaccine co-administration strategies for campaign and routine immunization programs. The participants will be randomly assigned to one of the six arms. The numbers are defined for each arm based on the sample size calculation. A list of children who did not receive MR, OCV and TCV will be prepared before enrollment by trained study staff (TSS). The TSSs will visit households in the defined study area and ask if the parents/guardians of children aged 12-59 months are willing to participate in the study. If they show willingness to participate, the TSSs will check their vaccination cards (if available) and prepare the list of potentially eligible children who have not received OCV, TCV and MR based on their vaccination card status and verbal statement (if vaccination card is not available). The investigators will enroll the participants after obtaining informed written consent and collect around 2-3 ml blood from each participant at different time points.
- Number of doses and intervals: Two doses, 2 weeks apart - Method of administration: Oral administration - Volume of vaccine to be administered: 1.5 mL/dose - Observational period: 4 weeks (2 weeks after each dose) - Number of visits: 3 visits 1. Visit 1: Screening and enrollment (1st dosing) 2. Visit 2: 2nd dosing 2 weeks after 1st dose (14+3 days) 3. Visit 3: 2 weeks after the 2nd dose (28+3 days), end of subject participation. This study will be carried out in healthy adults and children, at two sites, enrollment will be competitive between the sites. Subjects will be stratified according to age into adults (18~40 years of age) and children (1~17 years of age). According to the pre-generated randomization list, the participants will be randomized to the test or comparator groups (Visit 1) and will be given either the test vaccine or the comparator vaccine. For immunogenicity assessment, blood sample will be taken at Visit 1 (prior to vaccination), Visit 2 (prior to vaccination), and at the end-of-study Visit (Visit 3). For Safety assessment: the participants will be observed for 30 minutes post vaccination and instructed to record solicited adverse events that occur up to 6 days after vaccination on the participant diary card. This study is observer-blind: vaccine administrator and vaccine safety evaluator will be two distinct persons to avoid bias of safety assessment. Trial staff other than the vaccine administrator will remain blinded and will not handle the investigational product.
In order to assess whether the bivalent killed oral cholera vaccine may be used safely among infants who are most at risk for cholera, the investigators need to determine the safety and immunogenicity of the killed oral cholera vaccine among infants less than 1 year of age when given with the expanded program on immunization (EPI) vaccines including diptheria, pertussis and tetanus (DPT), oral polio vaccine (OPV), Hepatitis B vaccines and measles vaccine. Furthermore, the investigators also need to make sure that immune interference does not occur among all the other vaccine antigens given at the same time. Findings from this study will pave the way for the possible use of the killed whole cell oral cholera vaccine (OCV).