Syphilis Clinical Trials

27 recruitingLast updated: June 18, 2026

There are 27 actively recruiting syphilis clinical trials across 19 countries. Studies span Not Applicable, Phase 2, Phase 4, Phase 3. Top locations include Los Angeles, California, United States, Houston, Texas, United States, New Orleans, Louisiana, United States. Updated daily from ClinicalTrials.gov.


Syphilis Trials at a Glance

27 actively recruiting trials for syphilis are listed on ClinicalTrialsFinder across 6 cities in 19 countries. The largest study group is Not Applicable with 11 trials, with the heaviest enrollment activity in Los Angeles, Houston, and New Orleans. Lead sponsors running syphilis studies include The University of Texas Health Science Center, Houston, University of Washington, and Bangrak STIs Center.

Browse syphilis trials by phase

Treatments under study

About Syphilis Clinical Trials

Looking for clinical trials for Syphilis? There are currently 19 studies actively recruiting participants. Clinical trials offer access to new treatments before they are widely available, and every approved therapy in use today was first tested through a clinical trial.

Below you can browse trials, sign up for alerts when new Syphilis trials open, and view eligibility criteria for each study. Each listing includes the study phase, locations, and enrollment details.

Frequently Asked Questions

Common questions about Syphilis clinical trials

A clinical trial is a carefully designed research study that tests new medical treatments, drugs, devices, or approaches in human volunteers. Every approved medication and treatment available today was proven safe and effective through clinical trials.

All clinical trials are reviewed and approved by Institutional Review Boards (IRBs) — independent committees that evaluate patient safety. Trials follow strict protocols, and your health is monitored closely throughout. You can withdraw at any time.

Not necessarily. Many trials compare the new treatment against the current standard of care, meaning all participants receive active treatment. When placebos are used, they are typically combined with standard treatment, not given alone. The trial description will always specify the design.

Under the Affordable Care Act, most private insurers are required to cover routine patient care costs during a clinical trial. The sponsor typically covers the investigational treatment itself. Medicare also covers routine costs for qualifying trials.

Yes. Participation is completely voluntary. You can withdraw at any time, for any reason, without it affecting your access to standard medical care.

Each trial has specific eligibility criteria — including age, diagnosis, disease stage, prior treatments, and general health. Browse the trials listed above and check their eligibility sections. You can also contact the trial site directly to discuss your situation.

Showing 120 of 27 trials

Recruiting
Phase 2

Evaluation of Antimicrobial Prophylaxis to Prevent Syphilis in Pregnancy in Patients at Risk in Rio de Janeiro, Brazil

Congenital Syphilis
University of California, Los Angeles500 enrolled4 locationsNCT07189208
Recruiting
Phase 4

Doxycycline Prophylaxis for Prevention of Sexually Transmitted Infections

ChlamydiaSyphilisSexually Transmitted Infections (STIs)+1 more
Westat760 enrolled13 locationsNCT06738407
Recruiting
Phase 2

Comprehensive Ambulatory Antibiotics for the Treatment of Congenital Syphilis

Syphilis, Congenital
London School of Hygiene and Tropical Medicine90 enrolled3 locationsNCT06921213
Recruiting
Not Applicable

Offering Routine and Rapid Point of Care (POC) Syphilis Testing in Pregnant Patients Presenting to the Emergency Department

Syphilis
The University of Texas Health Science Center, Houston1,500 enrolled1 locationNCT06645106
Recruiting
Not Applicable

A Seek, Test, and Treat Intervention to Reduce Chlamydia Trachomatis Disparities

HIVChlamydiaSyphilis+1 more
Tulane University2,322 enrolled1 locationNCT06428643
Recruiting
Not Applicable

A Study to Evaluate Performance, Usability, and Contrived Result Interpretation of TruPlex HIV/HepB/Syphilis Rapid Test

hepatitis B infectionHIV-1-infectionSyphilis Infection+1 more
bioLytical Laboratories1,000 enrolled3 locationsNCT07563309
Recruiting
Phase 3

Cefixime Clinical Trial

Human Immunodeficiency VirusSyphilis
University of Southern California400 enrolled1 locationNCT04958122
Recruiting

Treponemal Shedding, Load, and Viability, in Women and Men-who-have-sex-with-women-only With Early Infectious Syphilis: Implications for Transmission

Syphilis
Monash University480 enrolled9 locationsNCT07300254
Recruiting
Not Applicable

Doxi-Rio: Study on the Use of Doxycycline to Prevent Sexually Transmitted Infections in Rio de Janeiro

HIV InfectionsSyphilisSexually Transmitted Diseases+2 more
Oswaldo Cruz Foundation200 enrolled1 locationNCT07500415
Recruiting

This Study Evaluates the ALPCO Syphilis-T and Syphilis-NT CLIA Kits for Detecting Syphilis Antibodies in Serum and Plasma. Samples From At-risk, HIV-positive, Pregnant, and Healthy Individuals Will Assess Assay Performance Versus Established Comparator Tests.

Syphilis InfectionSexually Transmitted Infection (STI)Treponema Pallidum+4 more
American Laboratory Products Company1,000 enrolled6 locationsNCT07089836
Recruiting
Phase 4

The Efficacy of Doxycycline Post Exposure Prophylaxis for Preventing STIs Among MSM in Bangkok, Thailand.

ChlamydiaGonorrheaSyphilis Infection
Bangrak STIs Center400 enrolled1 locationNCT07397403
Recruiting

Clinical Performance Evaluation of MagIA IVD-MD Multiplex Testing (HIV/HBV/HCV/Syphilis)

HIVHBVHCV+3 more
MagIA Diagnostics2,950 enrolled2 locationsNCT07170748
Recruiting
Not Applicable

Multiplo Tp/HIV Self-Test

HIV InfectionSyphilis Infection
Unity Health Toronto900 enrolled3 locationsNCT06716450
Recruiting
Not Applicable

A Cross-sectional Investigational Study to Evaluate the Sensitivity, Specificity, and Utility of the MedMira Inc. Multiplo® Complete Syphilis (TP/nTP) Antibody Test (POCT) to Diagnose Infectious Syphilis in Participants Attending the Sexual Health Clinic in Ottawa, Ontario.

SyphilisTreponema Pallidum
MedMira Laboratories Inc.1,300 enrolled1 locationNCT06586905
Recruiting
Not Applicable

Comparisons of Treatment Responses of Early Syphilis to Benzathine Penicillin G With or Without Doxycycline

Early Syphilis, Latent, Serological Relapse After Treatment
National Taiwan University Hospital688 enrolled9 locationsNCT06069141
Recruiting
Phase 4

Periodic Presumptive Treatment vs. doxyPEP for STI Control in Kenyan MSM

Gonorrhea MaleChlamydia (Male)Syphilis Male
University of Washington2,900 enrolled3 locationsNCT06468462
Recruiting
Not Applicable

Modernizing Perinatal Syphilis Testing

Syphilis
The University of Texas Health Science Center, Houston924 enrolled9 locationsNCT06082453
Recruiting
Not Applicable

The Integrated Female Sexually Transmitted Infection Testing for HIV Epidemic Control Through PrEP (IN-STEP) Study

HIVPrEP UptakeGonorrhea Female+3 more
Johns Hopkins University5,560 enrolled1 locationNCT06743204
Recruiting
Not Applicable

The Feasibility of Implementing Syphilis Point-of-care Testing Into a Prenatal Clinic for People Facing Barriers to Care

Syphilis
McMaster University77 enrolled1 locationNCT06829602
Recruiting
Phase 2

Daily Doxycycline for Early Syphillis

Syphilis
University of Washington15 enrolled1 locationNCT06683638