View clinical trials related to Yellow Fever.
Filter by:VYF03 is a phase II, randomized, parallel-group prevention study with 2 arms, active-controlled (Stamaril), observer-blind, multi-center study to assess the non-inferiority of the immune response, in terms of seroconversion rates of the investigational vaccine candidate vYF to the licensed Stamaril, in adults aged 18 years up to 60 years in Europe (EU). The safety and immunogenicity profile of vYF in a cohort of Asian population of Chinese origin outside of China will also be described. The study will also assess the immunogenicity profiles and the safety profiles of vYF and Stamaril. Participants will be randomized in a 2:1 ratio to receive a single subcutaneous injection of either the vYF vaccine (380 participants in EU and 80 participants of Chinese origin in Asia) or Stamaril (190 participants in EU and 40 participants of Chinese origin in Asia), on Day 01. The duration of each participant's participation will be approximately 5 years.
The primary objective of the study is to demonstrate the non-inferiority of the antibody response in terms of seroconversion rate 28 days after vaccine administration of one dose of yellow fever vaccine (vYF) compared to the antibody response after one dose of the YF-VAX control vaccine in yellow fever naïve participants. The secondary objectives of the study are: - To describe the immune response to yellow fever in both vaccine groups before and after vYF or YF-VAX administration. - To describe the safety profile of vYF vaccine in comparison to the safety profile of the control YF-VAX. - To describe the biosafety profile of vYF in comparison to the biosafety profile of the control YF-VAX.
Yellow fever is an acute febrile infectious disease transmitted to man urban cycle by mosquitoes infected by an arbovirus of the genus Flavivirus family Flaviviridae. Its occurrence is recorded in South America Central America and Africa. In cities the yellow fever vector is the Aedes aegypti mosquito which also transmits dengue viruses zika and chikungunya. This disease is more frequent in males and the most affected age group is above fifteen years due to the greater exposure related to the penetration in wild areas of the endemic zone of yellow fever. Another risk group is unvaccinated people who live near wild environments where the virus circulates. According to the World Health Organization a single dose of the yellow fever vaccine is sufficient to maintain protective immunity against yellow fever for a lifetime therefore a booster dose is not required. This question is difficult to evaluate because there is no serological correlate of protection against yellow fever and seropositivity is defined with several cut off points. Although studies indicate that the duration of protection after vaccination is long there is considerable evidence in the literature that antibody titer falls over the years reaching levels considered as seronegative in at least a portion of the vaccinees. This is of more concern to people living in endemic areas who are exposed to the virus throughout their lives. For this reason Brazil recommended revaccinating once at least until additional studies were done. The need to increase Bio Manguinhos production capacity to meet the increased demand from Brazil and other countries is urgent. The occurrence of epidemics when millions of individuals need to be vaccinated in a short period of time exceeds production capacity and this is a recurrent problem. The current vaccine has a very high potency well above the thousand international units recommended by World Health Organization. But we need to generate additional evidence that very low doses of viral particles in the yellow fever vaccine are still immunogenic and that their immunogenicity can be maintained for at least ten years after vaccination. This evidence will support the rapid increase of their availability by the fractionation of doses or other alternatives.
Hypothesis: Infections other than HIV can cause LN inflammation and collagen damage to the fibroblastic reticular cell network (FRCn), which will lead to CD4 T cell depletion and impaired vaccine responses. This protocol will study yellow fever vaccine (YFV) in two cohorts of people, one from Uganda and the other from Minnesota where we collect lymphoid tissues (LT) and peripheral blood monocytes (PBMCs) before and after vaccination using a new technique to catalog infectious burden of the individual, determine the relationship between IA, Infections, and immune response.
To determine the efficacy of metformin in reducing the rate of symptomatic YF17D infection, and to elucidate the effects of metformin on YF17D viremia and the downstream adaptive immune response, we hereby propose a randomised, double-blind, placebo-controlled clinical trial that is coupled with a system biology approach. We plan to recruit 44 healthy volunteers aged 21-40 years, with a Body Mass Index of 20-25 kg/m2, have no known drug allergies and are not currently receiving regular immune-modulating therapy such as metformin, NSAIDs, paracetamol, corticosteroids or statins. The age range that we propose will ensure that our volunteers are likely to be healthy and not be on long-term medication for other concurrent medical conditions. This would abrogate the confounding effect of YF17D infection enhancement by cross reactive antibodies that we have previously shown. Informed written consent will be obtained before any physical examination is performed. All consented subjects will undergo screening which includes a full physical examination, vital signs measurement, clinical laboratory tests and urine pregnancy test (for female subjects of child-bearing potential) Eligible subjects will be randomized 1:1 to either metformin 1000mg or placebo twice daily for 7 consecutive days (Days 1-7). On Day 4, subjects will be administered one dose of YF17D before study drug dosing. Aim 1 tests the hypothesis that prophylactic metformin reduces ER stress and thus attenuates the post-infection pro-inflammatory response for reduced rate of symptomatic outcome. The primary objective for Aim 1 is to determine the efficacy of metformin in reducing the rate of symptomatic YF17D infection using a randomized placebo-controlled clinical trial. Aim 2 explores the effectiveness of metformin, either through its action on ER stress or other pathways that differentially regulate the expression of pro- and anti-viral host factors, in inhibiting live attenuated vaccine infection and downstream adaptive immune responses. The primary objective for Aim 2 is to elucidate the effects of metformin on YF17D viremia and the downstream adaptive immune response.
A mobile suitcase laboratory for EBOV point-of-care (POC) detection at Ebola treatment centers was successfully implemented in Guinea during the large Ebola virus disease (EVD) outbreak in West-Africa 2014-2015. It was shown that isothermal amplification (Recombinase Polymerase Amplification (RPA)) could be efficiently used to test suspect EVD cases and local teams were trained in and successfully deployed with this fast method. In the frame of this project we want to train teams in DRC and expand RPA testing capacity to the differentials recommended by the WHO. Existing RPA assays for all parameters will be included into a multistrip for simultaneous use. This will be integrated with a simple biosafe extraction method. Implementing this approach and testing in the ongoing EVD outbreak will provide teams in DRC with response capacity for future EVD outbreaks.
The primary objectives of the study are: - To describe the safety profile of each of the 3 dosages of vYF and of YF-VAX® within the 28 days post-vaccination and up to the 6 months (Day 180) post-vaccination visit - To describe the antibody responses elicited by each of the 3 dosages of vYF and by YF-VAX on Day 0 pre-vaccination and then on Day 10, Day 14, Day 28 and 6 months (Day 180) post-vaccination overall and by baseline flavivirus serostatus - To quantify the detectable yellow fever (YF) vaccinal viremia in each vaccine groups (vYF and YF-VAX) in a subset of subjects on Day 0 visit, Day 1 visit, Day 3 visit, Day 5 visit, Day 7 visit, Day 10 visit, and Day 14 visit.
Investigating cytotoxicity of yellow fever specific CD8 T cells following YF-17D vaccination and the following licensing of these epitope-specific CD8 T cells
In the recent past there has been a number of large urban Yellow Fever outbreaks in sub-Saharan Africa, tropical South Americas, The demand for Yellow Fever vaccines in response to the large urban outbreaks occurring concurrently and the risk of further spread through Africa and to Asia was larger than the available global supply. In this situation, the World Health Organisation (WHO) developed recommendations for the use of fractional doses of Yellow Fever vaccine as a dose-sparing strategy. These recommendations were based on data from a limited number of clinical trials, none of which had been conducted in Africa. This was due to the uncertainties on the minimum dose requirement. Our study complements a study which is comparing full standard dose to 1/5th of standard dose of all four WHO-prequalified YF vaccines in adults (ClinicalTrials.gov number: NCT02991495), and is currently ongoing at KEMRI CGMRC and Epicentre, Mbarara which is designed to answer questions on the use of current stock of YF vaccines with a potency as close as possible to each manufacturers' minimum release. Data from this trial will inform a WHO recommendation on using 1/5th of the current standard dose of vaccine for outbreak control. However, since many vials will contain excess YF vaccine such that 1/5th of a vial is likely to be substantially above the current minimum potency requirements, these data may not be scientifically explanatory regarding the minimum dose required for preventive use. The new complementary study, aims to determine the lowest YF vaccine dose that is non-inferior to the current standard full dose among populations in sub-Saharan Africa. The study will be conducted in Kenya (KEMRI Center for Geographical Medicine Research-Coast (CGMR-C), Kilifi) and Uganda (Epicentre, Mbarara) with trial participants recruited at both sites, using vaccine from one WHO-prequalified manufacturer (Institut Pasteur de Dakar, Senegal (IPD)).
It concerns an investigation aiming to investigate genetic biological(s) marker(s) which allow to identify individuals who have risk of serious adverse events to the yellow fever vaccine. This testing is free of hypothesis, because these markers are still unknown. There is no intervention, and it is not possible to establish primary and secondary outcomes.