Suspended

Impact of Typhoid Vaccine on Immune System and Intestinal Bacteria in Adults

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Study Aim

This study aims to evaluate how the typhoid vaccine affects the immune system and intestinal bacteria in adults, by measuring the percentage of responders through the production of specific cytokines, Interferon-gamma or Tumor Necrosis Factor-alpha, post-immunization.

What is being tested

Vivotif Typhoid Oral Vaccine

Drug
Who is being recruted

Over 18 Years
See all eligibility criteria
How is the trial designed

Basic Science Study

Phase 4
Interventional
Study Start: October 2013
See protocol details

Summary

Principal SponsorUniversity of Maryland, Baltimore
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: October 24, 2013

Actual date on which the first participant was enrolled.

This study aims to understand how typhoid vaccines impact the immune system and intestinal bacteria. It focuses on adults who are scheduled for standard colonoscopies. The study uses Vivotif, a typhoid vaccine approved by the Food and Drug Administration (FDA) for travelers to developing countries. The research is important as it can help improve our understanding of how the body responds to typhoid vaccines, potentially leading to better vaccination strategies and care for those at risk of typhoid fever. Participants are divided into three groups. The first group receives the typhoid vaccine before the colonoscopy, the second group has a colonoscopy first, then gets the vaccine and a follow-up colonoscopy, and the third group has a colonoscopy without vaccination. Participants are asked to provide tissue, blood, saliva, and stool samples. The study measures the percentage of responders by looking at the production of certain proteins (Interferon-gamma or Tumor Necrosis Factor-alpha) in CD8+ cells after vaccination. A responder is defined as someone showing an increase of more than 0.1% of positive CD8+ cells for these proteins over baseline values.

Official TitleCVD 37000: Immunity and Microbiome Studies at Intestinal and Systemic Sites in Ty21a Vaccinated Adults
NCT03970304
Principal SponsorUniversity of Maryland, Baltimore
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

87 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Basic Science Study

Basic science studies help researchers understand how the body works or how a disease develops. They don't test treatments, but they build the foundation for future therapies.



Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

Over 18 Years

Range of ages for which participants are eligible to join.

Healthy volunteers allowed

If individuals who are healthy and do not have the condition being studied can participate.

Criteria

Inclusion Criteria: * Age 18 years and older * Undergoing colonoscopy for screening or surveillance for colorectal cancer at the University of Maryland * Provide written informed consent prior to initiation of any study procedures * Healthy, as defined by considered fit to undergo outpatient elective colonoscopy by the referring health care provider Exclusion Criteria: * Pregnancy or nursing mother * Known coagulopathy or bleeding disorder preventing mucosal biopsy * History of Crohn's disease or ulcerative colitis * Surgical removal of the ileocecal valve or any part of the small or large intestine * Allergic reaction to oral typhoid vaccine in the past * Immunosuppression from illness or treatment, including * immune-deficiency disorders such as Human Immunodeficiency Virus (HIV) or Acquired Immunodeficiency Syndrome (AIDS) * leukemia, lymphoma, or cancers * immune suppressive medications or treatments, such as corticosteroids or radiation * Receipt of any other vaccine two weeks prior to receipt of Ty21a * Positive urine pregnancy test (HCG) prior to colonoscopy or vaccination

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

This study does not include a placebo group 

Treatment Groups

Group I

Experimental
Participants undergo a colonoscopy, then receive Vivotif typhoid vaccine, followed by another colonoscopy. The vaccine is given in 4 doses, spaced apart by a few days.

Group II

Experimental
Participants receive Vivotif typhoid vaccine before a routine colonoscopy. During the procedure, small tissue samples are taken to study immune responses and gut bacteria.

Study Objectives

Primary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 1 location

Suspended

Universtiy of Maryland, Baltimore, Center for Vaccine Development and Global Health

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SuspendedOne Study Center