Typhoid Vaccine for Fear Response Studies

(FEIV Trial)

Overseen By Michael Srouji, BA

Age: 18 - 65

Sex: Any

Trial Phase: Phase 1

Sponsor: University of California, San Francisco

Disqualifiers: Inflammation, Pregnancy, others

Compensation: Varies

Number of Visits: 3

288 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how the immune system might influence the processing of fear and information. Researchers aim to determine if individuals receiving the Typhoid VI Polysaccharide Vaccine respond differently to fear than those receiving a harmless saline solution. Participants will have their reactions measured while listening to sounds and will complete questionnaires and tests. The trial seeks individuals aged 25-45 who have experienced trauma and either currently have PTSD or have never had PTSD. As a Phase 1 trial, the research focuses on understanding how the treatment works in people, offering participants a chance to contribute to groundbreaking research.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

Is there any evidence suggesting that the typhoid vaccine used in this trial is likely to be safe for humans?

Research studies have shown that the typhoid Vi polysaccharide vaccine is safe. Most recipients experienced no issues, and any side effects were usually mild, such as a sore arm at the injection site. One study found that a single dose of the vaccine effectively triggers an immune response. This vaccine is already approved for preventing typhoid. Overall, evidence suggests it is generally safe for people. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about using the Typhoid Vi Polysaccharide Vaccine to study fear responses because it offers a novel approach to understanding how our immune system might influence emotional processes. Unlike traditional treatments for fear-related conditions, which typically involve psychotherapy or medications like antidepressants, this vaccine might interact with the body’s immune system in a unique way by using a purified Vi polysaccharide from Salmonella typhi. This opens up new possibilities for exploring the connection between vaccines and psychological responses, potentially leading to innovative therapeutic strategies.

What evidence suggests that the typhoid vaccine could be effective for altering fear response?

Research has shown that the Typhoid VI Polysaccharide Vaccine effectively prevents typhoid fever. Studies indicate that this vaccine can reduce the risk of contracting typhoid fever by about 55% to 75% in adults. This conclusion comes from trials comparing the vaccine to a placebo, which demonstrated a clear reduction in confirmed cases of the disease. In the current trial, participants will receive either the Typhoid VI Polysaccharide Vaccine or a saline placebo. The vaccine boosts the body's immune system, helping it fight off the typhoid bacteria upon exposure. While this study examines the body's response to the vaccine, the main focus is on how well the vaccine can trigger an immune response. ^{1 6 7 8 9}

Who Is on the Research Team?

Aoife O'Donovan, PhD

Principal Investigator

University of California, San Francisco

Are You a Good Fit for This Trial?

This trial is for individuals with Post-Traumatic Stress Disorder (PTSD) who can attend four appointments at the San Francisco VA Health Care System. Participants will receive either a typhoid vaccine or a placebo and undergo tests to measure their physiological responses and complete psychological assessments.

Inclusion Criteria

Subjects must be trauma exposed

Subjects must have current PTSD or no history of PTSD

I am between 25 and 45 years old.

Exclusion Criteria

Pregnancy or plans to become pregnant in the next three months

Lack of skin conductance response to breathing and arithmetic tasks at screening visit

Contraindications to typhoid vaccine

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline Assessment

Participants undergo physiological testing of fear responses

1 day

1 visit (in-person)

Inflammatory Challenge

Participants receive either the typhoid vaccine or placebo and undergo physiological tests

1 day

1 visit (in-person)

Follow-up

Participants are monitored for physiological responses one week after the vaccine/placebo

1 week

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Typhoid VI Polysaccharide Vaccine

Trial Overview The study is testing whether a typhoid vaccine affects how people with PTSD process information and experience fear, compared to those receiving a saline placebo. It involves attending appointments, getting an injection, listening to sounds for response measurements, and doing questionnaires.

How Is the Trial Designed?

Group I: Polysaccharide typhoid vaccine Experimental Treatment 1 Intervention

Participants in this condition will receive an injection of 0.5ml Salmonella typhi capsular polysaccharide vaccine (Sanofi Pasteur, SA), which contains 25μg of purified Vi polysaccharide in a colorless isotonic phosphate buffered saline (pH 7±0.3), 4.150mg of sodium chloride, 0.065mg of disodium phosphate, 0.023mg of monosodium phosphate and 0.5ml of sterile water for injection.

Group II: Saline Placebo Arm Placebo Group 1 Intervention

Participants in this condition will receive and injection of 0.5ml of saline.

Who Is Running the Clinical Trial?

University of California, San Francisco

Lead Sponsor

Trials

2,636

Recruited

19,080,000+

San Francisco Veterans Affairs Medical Center

Collaborator

Trials

52

Recruited

211,000+

National Institute of Mental Health (NIMH)

Collaborator

Trials

3,007

Recruited

2,852,000+

Northern California Institute of Research and Education

Collaborator

Trials

30

Recruited

10,400+

Published Research Related to This Trial

The study involved 13 phobic individuals and 14 control subjects to assess their responses to a threat stimulus using manual muscle testing, revealing poor reliability in the results before controlling for confounding variables.

After adjusting for factors like musculoskeletal and attentional variables, the validity of muscle testing improved significantly to 91%, suggesting that these factors are crucial for accurately measuring emotional arousal in response to threats.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A preliminary inquiry into manual muscle testing response in phobic and control subjects exposed to threatening stimuli. Peterson, KB.[2007]

Citations

1. clinicaltrials.gov clinicaltrials.gov/ct2/show/NCT06630884

NCT06630884 | Inflammatory Challenge and Fear In our proposed study, we will use polysaccharide typhoid vaccine, which our preliminary data support as a robust acute inflammatory challenge, and a fear ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC4018880/

Immune Responses to Vi Capsular Polysaccharide ... The antibody levels in children who received this vaccine remained higher than those in children who received the control vaccine but were significantly reduced ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S2214109X2300606X

Efficacy of typhoid vaccines against culture-confirmed ... At 2 years, Vi-PS vaccine compared with the placebo probably reduces the incidence of typhoid fever (vaccine efficacy 56% [95% CI 40–68%]; four trials; 207 549 ...

4. fda.gov fda.gov/media/75993/download

Package Insert - Typhim Vi The protective efficacy for the Vi capsular polysaccharide (lyophilized formulation) group for blood culture confirmed cases of typhoid fever was 55% (95% CI: ...

5. jamanetwork.com jamanetwork.com/journals/jamainternalmedicine/fullarticle/621271

A New Typhoid Vaccine Composed of the Vi Capsular ... Protective efficacy was evaluated in two studies conducted in areas in which typhoid is endemic; the efficacy was 55% and 75%, respectively, in adults and in ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10793708/

Safety and immunogenicity of conjugate vaccine for ... Our study shows that a single dose of the Vi-DT vaccine is immunogenic, safe to administer and non-inferior to the Vi-TT vaccine four weeks after vaccination.

7. medsafe.govt.nz medsafe.govt.nz/profs/datasheet/t/typhimviinj.pdf

Typhim Vi Data Sheet The overall protective efficacy of Typhim Vi was 74%. (95% confidence interval (CI): 49% to 87%) for blood culture confirmed cases of typhoid fever during 20 ...

8. sciencedirect.com sciencedirect.com/science/article/pii/S0264410X15015297

A Japanese study to assess immunogenicity and safety of ... A single dose of typhoid Vi polysaccharide vaccine, Typhim Vi ® , demonstrated good safety and immunogenicity profile in a Japanese population.

9. cdn.who.int cdn.who.int/media/docs/default-source/pvg/global-vaccine-safety/typhoid-vaccine-rates-information-sheet.pdf?sfvrsn=706de51b_4

TYPHOID VACCINE An antibody response occurred in about 90% of subjects and lasted about 3 years. Vi-TT - There are no published large-scale prelicensure data or postlicensure ...