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

Trial Summary

Will I have to stop taking my current medications?

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

What data supports the effectiveness of the treatment Typhoid VI Polysaccharide Vaccine?

The Typhoid VI Polysaccharide Vaccine has been shown to be effective in preventing typhoid fever, with studies indicating a protective efficacy of up to 81% in vaccinated children compared to unvaccinated ones. Additionally, the vaccine is well-tolerated, with most people developing a strong immune response that lasts for about three years. ^{1 2 3 4 5}

Is the Typhoid Vi Polysaccharide Vaccine safe for humans?

The Typhoid Vi Polysaccharide Vaccine is generally safe for humans, with only minor reactions like mild fever or local reactions occurring in a small percentage of people. It is well tolerated in both children and adults, with most side effects being mild and temporary. ^{1 3 5 6 7}

How does the Typhoid VI Polysaccharide Vaccine differ from other treatments for fear response?

The Typhoid VI Polysaccharide Vaccine is unique because it is being studied for its effects on fear response, which is not a typical use for vaccines. Unlike standard treatments for fear or anxiety, which might include therapy or medication, this vaccine is being explored for its potential to influence fear mechanisms in the body. ^{8 9 10 11 12}

What is the purpose of this trial?

The goal of this study is to learn if short-term changes in the immune system alter how we process information and experience fear. The main questions it aims to answer are: Do people who receive typhoid vaccine respond differently than those who receive a placebo saline vaccine? Do people who receive typhoid vaccine experience changes in how they think and feel? Participants will: Attend four appointments at the San Francisco VA Health Care System; Receive typhoid vaccine or placebo at one of the visits; Have their physiological responding measured while listening to sounds; Complete questionnaires and psychological tests.

Research Team

Aoife O'Donovan, PhD

Principal Investigator

University of California, San Francisco

Eligibility Criteria

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

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)

Treatment Details

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.

Participant Groups

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+

Findings from Research

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]

References

1. United States pubmed.ncbi.nlm.nih.gov

A new typhoid vaccine composed of the Vi capsular polysaccharide. [2013]

2. England pubmed.ncbi.nlm.nih.gov

Population impact of Vi capsular polysaccharide vaccine. [2018]

3. England pubmed.ncbi.nlm.nih.gov

Protective activity of Vi capsular polysaccharide vaccine against typhoid fever. [2019]

4. Netherlands pubmed.ncbi.nlm.nih.gov

Persistence of antibody titres three years after vaccination with Vi polysaccharide vaccine against typhoid fever. [2019]

5. England pubmed.ncbi.nlm.nih.gov

Experience with Vi typhoid capsular polysaccharide vaccine in the U.K. [2019]

6. United States pubmed.ncbi.nlm.nih.gov

Lack of immune response to the Vi component of a Vi-positive variant of the Salmonella typhi live oral vaccine strain Ty21a in human studies. [2019]

7. China pubmed.ncbi.nlm.nih.gov

[Efficacy and side effects following immunization with Salmonella typhi Vi capsular polysaccharide vaccine]. [2006]

8. Australia pubmed.ncbi.nlm.nih.gov

The domino effect: adolescent girls' response to human papillomavirus vaccination. [2020]

9. United States pubmed.ncbi.nlm.nih.gov

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

10. Netherlands pubmed.ncbi.nlm.nih.gov

Relaxation training inhibits fear and arousal during in vivo exposure to phobia-cue stimuli. [2019]

11. United States pubmed.ncbi.nlm.nih.gov

Psychophysiological responses to presentation of a caged snake among behaviorally avoidant and non-avoidant college students. [2019]

12. Egypt pubmed.ncbi.nlm.nih.gov

The facial affective scale as a predictor for pain unpleasantness when children undergo immunizations. [2021]