Active clinical trials for "Typhoid Fever"

This study evaluates the effect of an oral typhoid vaccine on disruption of the intestinal barrier and response of the immune system. Intestinal and whole-body responses will be measured in all participants before and after the vaccine.

The purpose of this study is to use an existing, unique clinical cohort: the longitudinal cohort of younger (21-40 years) and elderly (>65 years) subjects whose yearly influenza vaccine responses have been studied extensively since 2007, to gain molecular and cellular mechanistic insights into the impaired vaccine responses in the elderly.

Iron deficiency (ID) anaemia (IDA) is a global public health problem, with the highest prevalence in Africa and in South-East Asia. While immunization programs have achieved high global coverage, vaccines often underperform in low- and middle-income countries (LMIC). The cause remains uncertain, but undernutrition, including ID, likely plays a role. Our recent in vitro and in vivo studies have shown the importance of iron status in adaptive immunity and vaccine response. Hypoferremia blunted T cell, B cell, and neutralizing antibody responses to influenza virus infection in mice, allowing the virus to persist. Iron deficient anaemic Kenyan women receiving intravenous iron at time of vaccination had a better immune response to the first dose of the ChAdOx Coronavirus 19 (COVID-19) vaccine and yellow fever vaccine. Japanese encephalitis and typhoid fever are endemic in Thailand. Vaccines are available but show variable efficacy. Whether ID impairs adult vaccine response to the live attenuated Japanese encephalitis (JE) and the Typhoid Vi polysaccharide (Vi-PS) vaccine and whether iron repletion via iron fortification improves vaccine response is uncertain. The objective of this study is to assess whether IDA in Thai women impairs immune response to the JE and the Typhoid Vi-PS vaccine and whether fortification iron improves their response. In this double-blind randomized controlled trial, IDA women will be assigned to two study groups: group 1 (fortification group) will receive iron-fortified biscuits (15mg iron as ferrous fumarate) for 56 days; group 2 (control group) will receive non-fortified biscuits for 56 days. All women will receive live attenuated JE and Typhoid Vi-PS vaccine on study day 28. Vaccine response will be measured 28 days after vaccination (on day 56) in both groups.

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.

In Kisantu Health Zone, approximate population 200,000, fever surveillance will be implemented in 8 health centers and 1 tertiary hospital. Individuals presenting to one of these study facilities with acute fever or history of fever or individuals presenting with suspicion of intestinal perforation irrespective of fever status, will be considered for enrollment. Following consent, blood samples (between 2.5 ml for children and 22 ml for adults) will be collected from eligible subjects and demographic and clinical information will be recorded in study forms at the time of enrollment at study health centers and hospitals. Peritoneal fluid and ileal tissue samples will be collected from surgical patients where possible. Biological specimens will be used for various testing, including microbiological culture of blood, tissue and peritoneal fluid for confirmation of bacterial growth, malaria diagnostics (microscopy and rapid testing), and storage of tissue samples for pathological investigation, and biobanking. Hospitalized patients will be followed-up to track clinical outcomes for the duration of hospitalization.

Acute undifferentiated febrile infection (AUFI) is a common presenting syndrome in low-resource settings and better diagnostics are urgently needed to improve patient management and guide disease prevention interventions. Assessment of the host gene expression response to infection in endemic populations has demonstrated significant promise as a new approach to identifying patients with enteric fever and for potential in differentiating between other causes of AUFI. Signatures identified through new data analytic techniques could be developed into a point-of-care test for use in endemic settings. In this multisite diagnostic evaluation study we will collect prospective clinical, laboratory and diagnostic data from two endemic settings to evaluate host gene expression signatures for detecting enteric fever and for determining the cause of AUFI in LMIC settings.

Fever management is a major problem in Low and Middle Income Countries (LMICs) where access to good quality diagnostic test is often unavailable. Fever due to typhoid is similar to other undifferentiated febrile illnesses and typhoid can be mistaken with other vector borne febrile illnesses such as scrub typhus. Currently available diagnostic tests, blood and bone marrow culture, and RDTs have several limitations including a low sensitivity and specificity . Recently, several antigens of Salmonella Typhi useful for serodiagnosis of typhoid has been identified. Salmonella Typhi lipopolysaccharide (LPS) and hemolysin E (HlyE) have been identified as top candidate antigens by several studies to differentiate acute typhoid patients from healthy individuals. DPP® Typhoid Assay is a multiplex rapid test that detects IgA antibodies to LPS and HlyE antigen. It is considered to have high sensitivity and specificity and its results were found to be highly correlated with ELISA results. However, very few studies have been conducted to evaluate this test and limited information about the accuracy of this test is present. Hence, this study will evaluate the sensitivity and specificity of this test in archived serum sample of well characterized blood culture positives and negatives in support of new innovation on typhoid diagnostics.

This protocol describes the challenge non-typhoidal Salmonella (CHANTS) study. This is a first-in-human phase 1, double-blinded, randomised, dose-escalation human infection study, conducted in healthy volunteers aged 18 to 50 years. The primary objective of the study is to perform a dose escalation with two strains (ST19 or ST313) to determine the infectious dose required for 60-75% of volunteers to develop Salmonellosis using a composite diagnostic criterion. The secondary objectives of the study are to describe and compare the clinical and laboratory features following controlled human infection. It is hoped that the successful establishment of an NTS human challenge model can be used in the future to test candidate vaccines for NTS disease.

This is an open-label, non-randomized study. The purpose of this study is to better understand how vaccines against typhoid fever affect the normal immune system and bacteria in the intestine. Patients having standard-of-care colonoscopies will be divided into 3 groups: Group 1: Vivotif typhoid vaccination then colonoscopy; Group 2: Colonoscopy, then Vivotif typhoid vaccination, then follow-up colonoscopy; Group 3: Colonoscopy without vaccination. The Vivotif typhoid vaccine used in this study is licensed by the Food and Drug Administration (FDA) for travelers to developing countries. Volunteers will be asked to donate tissue, blood, saliva and stool samples for studying how the body responds to the typhoid vaccine.

This study is to assess the safety and immunogenicity of Vi-DT vaccine in adults, adolescent, children and infants.