Understanding immune responses to typhoid and cholera vaccines

CVD 38000: Immunity, Microbiome, Epigenetics, and a Systems Biology Approach to the Study of Responses to Vaccination With Typhoid and/or Cholera

Phase 4 Interventional University of Maryland, Baltimore · NCT03705585

This study is testing how the typhoid and cholera vaccines affect the immune system and gut bacteria in people who are having endoscopies.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment240 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Maryland, Baltimore Academic / other
Locations1 site (Baltimore, Maryland)
Trial IDNCT03705585 on ClinicalTrials.gov

What this trial studies

This open-label, non-randomized study aims to investigate how the typhoid and cholera vaccines influence the immune system and intestinal bacteria. Participants scheduled for endoscopies will be divided into three groups: one receiving vaccinations before the procedure, another receiving vaccinations after, and a control group undergoing endoscopy without vaccination. The study will collect tissue, blood, saliva, and stool samples to analyze the immune response to the vaccines. Both vaccines used are FDA-approved for travelers to developing countries.

Who should consider this trial

Good fit: Ideal candidates are healthy adults aged 18 and older who are scheduled for an endoscopy at the University of Maryland Medical Center.

Not a fit: Patients who are pregnant, have a history of inflammatory bowel disease, or have had allergic reactions to the vaccines may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance our understanding of vaccine-induced immune responses, potentially leading to improved vaccination strategies.

How similar studies have performed: While studies on vaccine responses are common, this specific approach to studying typhoid and cholera vaccines in conjunction with endoscopic procedures is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* 1\. Age 18 years and older
* 2\. Already scheduled to undergo an EGD or colonoscopy for screening, surveillance, or a medically-indicated work-up at the University of Maryland Medical Center (main campus or Midtown)
* 3\. Able to provide written informed consent prior to initiation of any study procedures
* 4\. Healthy, as defined by considered fit to undergo outpatient elective EGD/colonoscopy by the evaluating health care provider

Exclusion Criteria:

* 1\. Pregnancy or nursing mother
* 2\. Known coagulopathy or bleeding disorder preventing mucosal biopsy
* 3\. History of Crohn's disease or ulcerative colitis
* 4\. For Subjects undergoing lower endoscopy (colonoscopy) only: Surgical removal of the ileocecal valve or any part of the small or large intestine (non-complicated appendectomy will be considered eligible)
* 5\. Allergic reaction to oral typhoid or cholera vaccine in the past
* 6\. Immunosuppression from illness or treatment, including

  1. immune-deficiency disorders such as Human Immunodeficiency Virus (HIV) or Acquired Immunodeficiency Syndrome (AIDS)
  2. leukemia, lymphoma, or cancers (localized non-melanoma skin cancers which are deemed inactive should be considered eligible)
* 7\. Receipt of any other vaccine two weeks prior to receipt of Ty21a or CVD 103-HgR
* 8\. Positive urine pregnancy test (HCG) prior to colonoscopy or vaccination

Where this trial is running

Baltimore, Maryland

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Typhoid and/or Cholera Vaccination
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.