Typhoid Vaccination
Conditions
Brief summary
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.
Interventions
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).
Sponsors
University of Maryland, Baltimore
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
Volunteers who choose to take part in this study will receive the licensed FDA approved Oral Typhoid Vaccine (Vivotif). Volunteers also have the possibility of being a control participant who will not be vaccinated.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Responders | 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. |
Countries
United States
Outcome results
None listed