Active clinical trials for "Dysentery, Bacillary"

Diarrhoea caused by Shigella (shigellosis) is of major public health importance. However, there are no licensed Shigella vaccines in routine use, with several candidates still in various stages of clinical development. Shigella human infection studies (HIS) have played a key role in vaccine development. These models also allow for the evaluation of immunity and other non-immunological parameters that are important to understand resistance and/or susceptibility to disease. This is particularly useful in individuals from endemic areas with varying levels of prior exposure and immunity to Shigella. Thus, establishing a Shigella HIS would enable the testing of interventions such as vaccines in a population that would most benefit from a subsequent vaccine and has potential to accelerate vaccine development. Here, the goal is to successfully establish a Shigella sonnei human infection model in Kenyan adults. This will be achieved by conducting dose-finding and dose verification Shigella studies that safely and reproducibly induce ≥60% attack rates. In this study, investigators aim to use Shigella HIS in healthy adults to develop a model as a platform to test vaccines, to study immune responses identifying potential correlates of infection, and non-immunological factors mediating and influencing susceptibility to disease. To achieve this, the study will be carried out in two phases over a period of 12-14 months. Phase A will enroll (N=up to 40 volunteers) and Phase B will enroll an additional (N=30 volunteers). To be eligible to receive a dose of 53G, volunteers must pass the screening visit. Investigators will vary the dose of bacteria in individuals enrolled for challenge to identify the dose needed to cause ≥60% shigellosis (attack rate) (Phase A) followed by testing and demonstrate the reproducibility of the model (Phase B). Thus, the main outcomes of the study will be: (1) optimisation of bacterial dose for infection success (≥60% attack rate); and (2) safety.

This is a trial to evaluate the safety, reactogenicity, immunogenicity and efficacy of a 10^6 cfu dose of an oral live-attenuated S. sonnei vaccine candidate, WRSs2, in up to 120 healthy males and non-pregnant females aged 18-49, inclusive. This is a two-phase study, an outpatient WRSs2 vaccination phase and an inpatient S. sonnei 53G challenge phase. Subjects will be randomized 1:1:1 into one of three vaccination arms. Outpatient WRSs2 phase: Arm 1 will receive two doses of WRSs2 vaccine; Arm 2 will receive one dose of the placebo and one dose of WRSs2 vaccine; Arm 3 will receive two doses of the placebo. All three arms will then be admitted to an inpatient unit and given one dose of S. sonnei 53G challenge. The study will be conducted in up to 3 Vaccine Treatment Evaluation Units (VTEU) sites. The study duration is approximately 24 months with subject participation duration approximately 8 months. The Primary Objective of this study is to estimate vaccine efficacy of 1 and 2 doses of WRSs2 in preventing shigellosis, following challenge with S. sonnei strain 53G.

Shigellosis is a major cause of morbidity and mortality in young children in Bangladesh and other developing countries. Further, the increasing emergence of resistance to a wide range of antibiotics is of great concern. Another major public health problem in Bangladesh is malnutrition, which is closely linked with shigellosis and with a high mortality. In Shigellosis, a heavy nutritional burden is placed on children and vital micronutrients such as vitamin A is lost in the urine. We recently found that the immune response in S. Flexneri infection was lower in children who were severely malnourished (weight-for-age≤65% as a percentage of the National Centre for Health Statistics median) when compared to children with weight-for-age from >65-75%. T cell responses were primarily affected with lowered CD4/CD8 ratios, lowered proliferative responses to T cell mitogens, Conconavalin A (ConA) and phytohaemagglutinin (PHA). However, proliferation of pheripheral blood mononuclear cells (PBMs) was lowered only in the presence of autologous plasma suggesting that a factor(s) in plasma, probably nutritional, rather than a defect in cells themselves was responsible. In children with S. dysenteriae 1 infection, proliferative responses to PHA were similarly lowered in the presence of autologous plasma but inhibition correlated to lowered transferring levels in plasma and not to the weight-for-age of the children. Also severely malnourished children with either S. flexneri or S. dysenteriae 1 infection were more severely ill. These findingings show that immunity in malnourishrd children with shigella infection is impaired which may lead to more severe illness. As zinc has profound effects on immunity as well as clinical outcome in diarrhoeal diseases, it is possible that zinc deficiency may be a factor in reducing immunity and increasing severity of acute illness in malnourished children with shigellosis. In this study, we will investigate the effect of zinc supplementation, in a double blind placebo controlled trial, on inflammatory responses, outcome of acute illness and growth following recovery from acute illness with S. flexneri infection.

The purpose of this study is to assess the efficacy of 3 days of azithromycin (AZI) compared to 3 days of ciprofloxacin (CIP) (standard-of-care) for the treatment of children hospitalised with dysentery in Ho Chi Minh City.

The purpose of this study is to determine whether CVD 1208S (a live, attenuated, oral vaccine) is safe and effective in the prevention of Shigella infection.

This is a research study about an experimental (investigational) oral inactivated whole cell Shigella flexneri 2a killed vaccine (Sf2aWC). Sf2aWC is a killed vaccine that is being made to prevent disease from Shigella., which causes bloody, watery diarrhea. Infants and children living in developing countries experience the greatest consequences of this disease. The purpose of this study is to find a dose of the vaccine that is safe, tolerable, and develops an immune response. About 82 healthy adults, ages 18-45, will participate in this study. This study will require volunteers to stay in the research facility for several nights for the first dose. Participants in Cohorts 2, 3, and 4 will not be required to stay overnight for the second and third doses. Participants will be assigned to receive 1 of 4 vaccine doses by mouth. Study procedures include: stool samples, blood samples and documenting side effects. Participants will be involved in study related procedures for about 8 months.

The purpose of this study is to determine whether CVD 1208S (a live, attenuated, oral vaccine) is safe and effective in the prevention of Shigella infection.

This is a research study about an experimental (investigational) oral inactivated whole cell Shigella flexneri 2a killed vaccine (Sf2aWC) and an adjuvant called dmLT. Sf2aWC is a killed vaccine that is being made to prevent disease from Shigella., which causes bloody, watery diarrhea. An adjuvant is something that is added to a vaccine to make it work better. The purpose of the study is to see if the vaccine will protect people from Shigella infection with or without an adjuvant called dmLT. About 72 healthy adults, ages 18-45, will participate in this study. The study will compare 2 different vaccination groups and 1 control group. Volunteers have an equal chance to be in any of the 3 groups. Study procedures include: stool samples, blood samples and documenting side effects. Participants will be involved in study related procedures for about 6 months.

The purpose of this study is to evaluate the safety and the immunogenicity of two different doses of the GVGH S. sonnei vaccine in healthy adults and represents the first step towards testing of the GMMA vaccine in the vaccine target population of children from developing countries where shigellosis is endemic.

This is a first-in-human, single-center, single-blinded, observer-masked randomized, dose escalation (two doses), placebo-controlled study in healthy volunteers.