Recruiting
Phase 1

Typhoid Vaccine

Sponsor:

UCLA

Code:

NCT06630884

Conditions

Posttraumatic Stress Disorder (PTSD)

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Accepted

Interventions

Typhoid VI Polysaccharide Vaccine Injectable Solution

Saline Placebo (0.5mL injection)

Study Details

Brief summary:

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.

Conditions

Posttraumatic Stress Disorder (PTSD)

Study ID

NCT06630884

Start date

Mar 28, 2025

Status verified date

Dec, 2025

Completion date

Nov, 2028

Anticipated

Primary completion date

Nov, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Accepted

Inclusion Criteria:

All Subjects:

1. Aged 18-60 years old
2. Trauma Exposed
3. Current PTSD/No history of PTSD

Exclusion Criteria:

1. Contraindications to typhoid vaccine
2. Conditions associated with inflammation
3. Pregnancy or plans to become pregnant in next three months

Study Design

Enrollment

288 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Polysaccharide typhoid vaccine

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.

placebo comparator: Saline Placebo Arm

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

Interventions

Typhoid VI Polysaccharide Vaccine Injectable Solution

Salmonella typhi capsular polysaccharide vaccine (Typhoid Vi Polysaccharide Vaccine): Each dose of 0.5ml Salmonella typhi capsular polysaccharide vaccine (Sanofi Pasteur, SA) is formulated to contain 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. It is indicated for use by humans aged 2 years and older for protection against typhoid fever.

Saline Placebo (0.5mL injection)

The placebo injection will consist of 0.5mL of saline.

Primary outcome measure

  • Skin conductance response (SCR) [ Time Frame: SCR will be assessed at baseline, 4.5 hours, and one week after vaccine/placebo. ]

Central Contacts and Locations

Central contacts

Aoife O'Donovan, PhD

415-221-4810aoife.odonovan@ucsf.edu

Michael Srouji, BA

415-221-4810

Locations

San Francisco VA Health Care System

Recruiting

San Francisco, California, United States, 94121

More Information

Sponsor

University of California, San Francisco

Last update posted

Dec 15, 2025

Last verified

Dec, 2025

Keywords

  • PTSD
  • posttraumatic stress
  • inflammation
  • fear

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of California, San Francisco on 2025-12-15.