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NCT Number: NCT03970304

CVD 37000: Immunity and Microbiome Studies at Intestinal and Systemic Sites in Ty21a Vaccinated Adults

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.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

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Key information

Conditions

Typhoid Vaccination

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

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

Baltimore, Maryland, 21201, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Vivotif Typhoid Oral Vaccine

Drug

The 4 doses (1 capsule each) will be administered on alternate days, e.g., days 0, 2, 4, and 7 (± 1 day) under the supervision of the study coordinator(s).

Other names: Ty21a Typhoid Oral Vaccine

Primary outcomes

  1. Percentage of Responders

    Time frame: approximately 5 years

    Percentage of responders by cytokine production (Interferon-gamma (IFN-gamma) or Tumor Necrosis Factor-alpha (TNF-α)) by mass cytometry or flow cytometry. Responders will be defined as those volunteers showing increases post-immunization of >0.1% of positive CD8+ cells for IFN-gamma or TNF-α over baseline (pre-immunization) values.) or Tumor Necrosis Factor-alpha (TNF-α)) by mass cytometry or flow cytometry.

Sponsors and collaborators

Lead sponsor

University of Maryland, Baltimore

Other

Registry information

Important dates

Study start
2013
Primary completion
2027
Study completion
2027
First posted
May 31, 2019
Registry last updated
Jan 7, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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