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Intestinal PermeabilityEarly Phase 1NCT04083950

Induction of Gut Permeability by an Oral Vaccine

A Early Phase 1 study testing Vivotif Typhoid Oral Vaccine in people with Intestinal Permeability and Inflammation, run by USDA, Western Human Nutrition Research Center at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

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. Read more about this study

Who is it for?
Ages 18 to 49 years, women onlyHealthy volunteers can take part
Conditions the study is for
Intestinal Permeability, Inflammation, Vaccine
What is being tested?
Vivotif Typhoid Oral Vaccine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
10 participants
Where
1 siteUnited States
Study dates
4 Dec 2019to 30 Sep 2026
Phase
Early Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 49 years
  • Women only
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Body Mass Index (BMI) 18.5 - 29.9 kg/m2

Who cannot join

  • Has HIV/AIDS or another disease that affects the immune system
  • Has any kind of cancer
  • Decline to take an HIV blood test
  • Blood pressure greater than or equal to 140/90 mmhg
  • Pregnant or lactating women
  • Refusal to take a pregnancy test prior to the study
Show all 38Show fewer
  • Refusal to use a method of birth control during the study
  • Allergy to vaccine components, i.e. Thimerosal and enteric-coated capsules
  • Allergy to oral typhoid vaccine
  • Allergy to aspirin
  • Daily use of blood thinners
  • Use of anti-inflammatory medications, i.e. nonsteroidal anti-inflammatory drugs (NSAID), aspirin, 3 or more times per month
  • Use of sulfonamides or antibiotics in the past 30 days
  • Use of anti-hypertensive drugs, i.e. beta blockers, diuretics, calcium channel blockers
  • Use of anti-malaria drugs, i.e. Mefloquine, chloroquine, and proguanil
  • Use of drugs that affect the immune system, i.e. immunosuppressants, immune-modifying drugs, corticosteroids, i.e. cortisone, prednisone, methylprednisolone, for 2 weeks or longer
  • Is taking cancer treatment with radiation or drugs
  • Greater than ten years residence in a typhoid-endemic area
  • Receipt of typhoid vaccine in the last 5 years
  • Receipt of any vaccine two weeks prior to receipt of Ty21a vaccine
  • Individuals at increased risk of developing complications from a live, bacterial vaccine
  • History of typhoid fever
  • History of primary immune deficiency or autoimmune disease
  • History of acute or chronic gastrointestinal (GI) disorder, i.e. Crohn's disease, irritable bowel syndrome, gastric ulcer
  • Diarrheal illness (defined as passing 3 or more abnormally loose or watery stool in a 24 hour period) or persistent vomiting 2 weeks prior to the study
  • History of bleeding disorder, including bleeding from the GI tract
  • History of chronic illnesses, i.e. diabetes, cardiovascular disease, cancer, gastrointestinal malabsorption or inflammatory diseases, kidney disease, autoimmune disorders, HIV, liver disease, including hepatitis B and C.
  • Asthma if taking medication on a daily basis
  • Recent surgery (within 3 months)
  • History of GI surgery
  • Recent hospitalization (within 3 months)
  • Acute febrile illness (within 2 weeks)
  • Unwillingness to discontinue consumption of artificial sweeteners in foods or drinks, i.e. sport drinks, coconut water, "diet" drinks and foods (possibly containing sucralose)
  • Not having at least one arm vein suitable for blood drawing
  • Unwilling or uncomfortable with blood draws seven times in 29 days
  • Regular blood or blood product donation and refusal to suspend donation
  • Current participation in another research study
  • Unable to fast for 12-16 hours

Trial locations and contacts

1 site in 1 country.

United States1 site

  • USDA, ARS, Western Human Nutrition Research Center

    Davis, California, 95616

Other trials in United States

About this study

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.

Read the detailed description

The licensed Ty21a vaccine strain of S. enterica Typhi is routinely used by travelers to countries where typhoid is common. It is not known whether the vaccine causes measurable changes in intestinal permeability and whether changes in permeability are correlated with the magnitude of the vaccine response. In the current study, gut permeability will be measured in participants at baseline and after an aspirin challenge, which is known to disrupt intestinal permeability, and after the first, second, and fourth doses of a the Ty21a vaccine. Intestinal permeability will be measured using a three-sugar absorption test composed of lactulose, mannitol, and sucralose and by several plasma markers. Vaccine response will be measured by quantitating T cells and newly developed IgG-or IgA-secreting plasma cells specific for Ty21a.

Being tested
Vivotif Typhoid Oral Vaccine, Aspirin (Positive Control)
Keywords
Gastrointestinal Health, Intestinal Permeability, Inflammation, Vaccine Response, Ty21a Typhoid Vaccine, Typhoid Fever
Medical subject headings
Inflammation, Typhoid Fever

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Vivotif Typhoid Oral VaccineBiological

    Also called Ty21a Typhoid Oral Vaccine

    One capsule is swallowed on alternate days, e.g. days 15, 17, 19, and 21, for a total of 4 capsules.

  • Aspirin (Positive Control)Drug

    Also called Aspirin Challenge

    Three tablets (325 mg aspirin in each tablet or 975 mg total) are swallowed on days 2 and 3.

Study groups in NCT04083950
Study groupRoleWhat they receive
Single groupExperimentalAll participants will receive the vaccine and aspirin.
Receives: Biological: Vivotif Typhoid Oral Vaccine; Drug: Aspirin (Positive Control)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in intestinal permeability

    Measurement of sugar (lactulose, D-mannitol, and sucralose) excretion in urine.

    Measured: Day 1, 3, 16, 18, and 22

Secondary outcomes (8)

  1. Antibody response to typhoid vaccination

    Measurement of Typhi-specific immunoglobulin G (IgG) and immunoglobulin A (IgA) plasma cells in peripheral blood using the antibody in lymphocyte supernatant assay.

    Measured: Day 1, 18, 22, 24, and 29

  2. T-cell response to typhoid vaccination

    Measurement of vaccine-specific cluster of differentiation 4 (CD4) and cluster of differentiation 8 (CD8) T-cells in peripheral blood mononuclear cells.

    Measured: Day 1, 22, and 29

  3. Change in markers of inflammation

    Measurement of plasma cytokines, chemokines, and acute phase proteins by a multiplex immunoassay.

    Measured: Day 1, 3, 16, 18, 22, and 24

  4. Change in intestinal fatty acid binding protein (iFABP)

    Measurement of plasma iFABP.

    Measured: Day 1, 3, 16, 18, and 22

  5. Change in D-lactate

    Measurement of plasma D-lactate.

    Measured: Day 1, 3, 16, 18, and 22

  6. Change in diamine oxidase

    Measurement of plasma diamine oxidase.

    Measured: Day 1, 3, 16, 18, and 22

  7. Change in lipopolysaccharide binding protein (LBP)

    Measurement of plasma LBP.

    Measured: Day 1, 3, 16, 18, and 22

  8. Change in citrulline

    Measurement of plasma citrulline.

    Measured: Day 1, 3, 16, 18, and 22

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted10 Sep 2019
  2. Study start4 Dec 2019
  3. Primary completion31 Jan 2022
  4. Study completion30 Sep 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Early Phase 1
Primary purpose
Basic science
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
10 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04083950
Sponsor's protocol ID
FL109
Status last verified
Nov 2025
First submitted
5 Sep 2019
Last updated
24 Nov 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Early Phase 1 study testing Vivotif Typhoid Oral Vaccine in people with Intestinal Permeability and Inflammation, run by USDA, Western Human Nutrition Research Center at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 38 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 24 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in intestinal permeability (time frame: Day 1, 3, 16, 18, and 22). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04083950.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Nov 2025.

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