Active clinical trials for "Typhoid Fever"

The purpose of this study is to evaluate the impact of a government-led typhoid conjugate vaccine introduction program on typhoid disease burden in Navi Mumbai, India.

Typhoid fever (typhoid) is an enteric bacterial infection caused by Salmonella enterica serovar Typhi (Salmonella Typhi; S. Typhi). It is one of the most common bacterial causes of acute febrile illness in the developing world, with an estimated 10.9 million new cases worldwide and 116.8 thousand deaths in 2017. Like many febrile illnesses, typhoid presents with non-specific symptoms and signs, especially in its early stages. In routine healthcare settings in low- and middle-income countries (LMIC), typhoid fever is commonly suspected and treated empirically with antibiotics. This overuse of antibiotics creates a selective pressure for the development of antimicrobial resistance (AMR), that has resulted in the emergence and spread of typhoid strains that are resistant to all first-line antibiotics. Similarly, the low specificity of current rapid diagnostic tests (RDTs) can lead to an over diagnosis of typhoid fever that may result in the overuse of antibiotics and delay the proper treatment for underlying conditions. FIND in collaboration with international typhoid experts developed a target product profile outlining the ideal characteristics of point of care tests. As part of this activity it became apparent that no quality data are available that systematically compare all available commercially point of care tests against the same set of reference standards used in multiple populations (e.g. Africa vs Asia). This lack of benchmarking data significantly impedes health provider's ability to decide on the utility of commercial tests in different settings, ultimately restricting use and access. Further the lack of well characterized samples reduces the ability for targeted innovation in the typhoid space. The current study aims to benchmark different commercial typhoid tests against a defined reference standard applied in multiple population and simultaneously develop a sample set that can be used in future evaluations of emerging technologies and/or to support innovative test development.

Typhoid fever results from infection with a bacterium called Salmonella Typhi and is a major cause of illness worldwide. It is estimated to infect 20-25 million people every year and can affect people of all ages, but is particularly common in young children. The disease is spread through contaminated food and water, and efforts to improve water quality, sanitation and hygiene will likely go a long way to reducing the global burden of disease. Unfortunately, improving access to clean water and sanitation improvements is very costly and difficult to implement on a large scale. Vaccination against typhoid fever is likely to be a cost-effective way of reducing the global disease burden. There are two vaccines currently available against typhoid fever. Whilst these vaccines provide some protection against disease (in the region of 50-70%) these vaccines are less effective in young children, who are the population group at highest risk of disease. In order to develop a new generation of typhoid vaccines it is important to have a more complete understanding of how the bacterium causes disease. In this study, the investigators are aiming to understand more about the Salmonella Typhi bacteria and how it causes disease. In particular, the investigators aim to study the importance of a toxin produced by the typhoid bacteria, called the typhoid toxin. The typhoid toxin has only recently been discovered. It is made only by the typhoid bacteria and closely related bacteria, such as paratyphoid. From studies done in the laboratory, there is evidence that the typhoid toxin is important in causing typhoid disease. It is thought that the typhoid toxin might be important in causing symptoms of typhoid disease, however the exact role of the typhoid toxin during infection in humans hasn't been studied before. Studying this might impact on the design new vaccines against typhoid. In this study, the investigators will be undertaking a 'challenge' with two strains of the typhoid bacteria (Salmonella Typhi). This involves exposing participants to live Salmonella Typhi under defined circumstances, by asking them to swallow a solution that contains the bacteria. After the challenge the investigators closely monitor participants for a period of at least two weeks and the investigators will then treat participants with antibiotics as soon as they are diagnosed with typhoid disease. The investigators are interested in comparing the response to challenge between two strains of the typhoid bacteria that differ in the production of the typhoid toxin. This process has been undertaken by participants in previous Oxford Vaccine Group studies since 2011.

Typhoid fever caused by Salmonella Typhi and Paratyphi causes over 21 million cases of febrile illness and 200,000 deaths are attributed to enteric fever each year. Typhoid fever is an enteric infection that results in febrile illness. Typhoid fever causes significant morbidity in the developing world especially young children.S. Typhi specific antibody responses are elicited in typhoid fever and following typhoid vaccination. Cross-reactive multifunctional CD+4 T cell mediated IL-17 responses have been shown in typhoid fever. As S. Typhi as an intracellular pathogen, cellular immune responses might be central to protection. S. Typhi peptide subunit vaccine elicits CD+4 T cell responses that correlate with protection in mice. The role of mucosal associated invariant T cell (MAIT) and natural killer (NK) cell responses in typhoid fever or following vaccination remain poorly understood. Transcriptome profiling of human immune responses to S. Typhi infection is not clearly understood. Establishing successful infection by S. Typhi evasion of T cell and neutrophil responses need to be investigated to better understand the correlates of protection.

To develop a rapid, sensitive, and inexpensive diagnostic method, as well as more efficacious vaccine, for countries where typhoid fever remains a major public health burden.

This is a multicenter (at travel clinics), phase 4 observational prospective cohort study in healthy adult male and female travelers for whom typhoid vaccination with Vivotif is recommended, as per standard practice.

Typhoid fever remains an important cause of morbidity and mortality in the developing world. It is estimated that more than 16 million cases and about 600,000 deaths occur annually, most of which occur in Southeast Asia and Africa. Ingestion of food or water contaminated by acutely infected persons or chronic carriers is the most common form of transmission. As a result, typhoid fever is prevalent where unsafe drinking water or contaminated food is common. Typhoid fever is highly endemic in Vietnam, especially in the southern provinces and is a significant disease in both preschool and school-aged children. Data from Dong Thap Provincial Hospital, Mekong delta region showed that among 3,934 hospitalized typhoid fever cases from 1990 to 1995, 4.2% had complications and 0.8% died. Typhoid fever has become difficult and expensive to treat. About 90% of Salmonella typhi isolates are of multidrug-resistant (resistant to chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) and 76% of isolates showed reduced susceptibility to fluoroquinolones. Isolates with full fluoroquinolone or extended spectrum cephalosporin resistance have not yet reported in Vietnam but occur sporadically in the Indian subcontinent. If they become widespread, alternative treatment options will be limited. The improvement of sanitation, provision of safe water and elimination of chronic carriage is not expected to be achieved quickly. Accordingly, vaccination against typhoid fever is increasingly important national public health priority.

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 study aims to perform a head to head comparison of 11 typhoid tests currently in the market and simultaneously develop a sample set that can be used in future evaluations of emerging technologies. The central objective is to evaluate different Typhoid Rapid Diagnostic Tests (RDTs) that are commercially available internationally for detecting antigens or antibodies to Salmonella Typhi and use Blood culture as standard for comparison. The end point will be to determine estimates of sensitivity and specificity for each test, with 95% confidence interval, using blood culture as reference.