Understanding how inflammation affects fear responses in PTSD

Inflammatory Challenge and Fear Extinction: A Model to Enhance Understanding of Posttraumatic Stress Disorder

Phase 1 Interventional University of California, San Francisco · NCT06630884

This study is testing how short-term changes in the immune system affect fear responses in people with and without PTSD by giving them a vaccine or a placebo while they listen to sounds.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment288 (estimated)
Ages18 Years to 60 Years
SexAll
SponsorUniversity of California, San Francisco Academic / other
Locations1 site (San Francisco, California)
Trial IDNCT06630884 on ClinicalTrials.gov

What this trial studies

This study investigates the impact of short-term immune system changes on fear processing in individuals with and without posttraumatic stress disorder (PTSD). Participants will receive either a typhoid vaccine or a placebo and undergo physiological measurements while listening to sounds, as well as complete psychological assessments. The research aims to uncover how inflammation influences fear responses, particularly in trauma-exposed individuals, to inform future treatments for PTSD. The study is conducted at the San Francisco VA Health Care System and involves four appointments for each participant.

Who should consider this trial

Good fit: Ideal candidates are trauma-exposed individuals aged 25-45, with current PTSD or no history of PTSD.

Not a fit: Patients with contraindications to the typhoid vaccine or conditions associated with inflammation may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved treatments for PTSD by targeting inflammation-related mechanisms.

How similar studies have performed: While the specific approach of this study is novel, previous research has indicated that inflammation can affect fear responses, suggesting potential for success.

Eligibility criteria

Show full inclusion / exclusion criteria
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

Where this trial is running

San Francisco, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Posttraumatic Stress DisorderPTSDposttraumatic stressinflammationfear
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.