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Home › Conditions › Syphilis

Syphilis

Part of Treponemal Infections

15 published articles · Updated continuously

Clinical Trial Landscape

Clinical Trials for Syphilis

10 trials tracked for Syphilis: 4 in phase 3 or 4 and 3 with published results. The most-cited published study has 467 citations.

10Trials tracked
4Phase 3 & 4
0Recruiting
3With published results
Phase distribution
Phase 4 4 Phase 2 1 Other / NA 5
  1. Phase 4 Evaluation of Doxycycline Post-exposure Prophylaxis to Reduce Sexually Transmitted Infections in PrEP Users and HIV-infected Men Who Have Sex With Men Completed · 467 cited
  2. Phase 4 Syphilis Response to Higher Penicillin Dosage: The 2.4 Versus 7.2 Study Completed · 34 cited
  3. Phase 4 Phase 4 Comparative Trial of Benzathine Penicillin G for Treatment of Early Syphilis in Subjects With or Without HIV Infection Completed · 15 cited
  4. Phase 4 Syphilis Self-testing to Expand Test Uptake Among Men Who Have Sex With Men (SST) Completed
  5. Phase 2 Cefixime for Alternative Syphilis Treatment Completed
  6. N/A Lumbar Puncture and Syphilis Outcome Completed
Show 4 more trials
  1. N/A mLab App Plus: A Randomized Controlled Trial of a Mobile Health (mHealth) Intervention Completed
  2. N/A Combination Primary Care and Prevention Services for Women Who Inject Drugs and Exchange Sex in Seattle, Washington Completed
  3. N/A Zenyth: Motivational Interviewing-based Telehealth Intervention for Bacterial Sexually Transmitted Infection Screening Completed
  4. N/A Ending the HIV Epidemic Through Point-of-Care Technologies (EHPOC) Completed

Showing the 10 most-cited and recently-updated of 10 trials. Browse the full registry →

Trial data sourced from ClinicalTrials.gov. Counts describe the research landscape and are not a treatment recommendation. Informational only — not medical advice.

What the trials found Updated — new results For clinicians

Syphilis: what the trials found

Benzathine penicillin G intramuscular treatment is established for syphilis management, with specific evidence showing a significant serological response by month 6 in patients receiving the intervention 5. Furthermore, there is documented efficacy regarding adherence to dosing schedules during prescribed visit windows 5.

Doxycycline Hyclate Delayed-Release (200 mg) and facility-based syphilis testing are also established interventions within the current clinical evidence base [3, 6].

Recent results — preliminary, needs further review

  • The use of Cepheid GeneXpert HIV-1 Qual POC HIV VL tests is currently being evaluated 1.
  • Mobile Van Clinics have been utilized as a delivery method for care 2.
  • Motivational interviewing combined with specimen self-collection has been explored to improve engagement and specimen return rates 8.

For the clinician treating this condition

  • Benzathine penicillin G is associated with significant serological responses by month 6 in patients treated for syphilis 5.
  • Doxycycline Hyclate Delayed-Release (200 mg) and facility-based testing are established clinical options [3, 6].

AI synthesis of 4 cited trials, updated Jun 29, 2026. Informational only — not medical advice; trial data sourced from ClinicalTrials.gov. How we use AI.

HCP Mode — summaries include clinical detail, trial data, and statistical outcomes.
Patient Mode — summaries use plain language, avoiding clinical jargon.
Doxycycline is the best supported alternative to benzathine penicillin for treating infectious syphilis
Infectious Disease Sys. Review
Doxycycline is the best supported alternative to benzathine penicillin for treating infectious syphilis Doxycycline shows promise as syphilis treatment alternative
This systematic review and network meta-analysis of 1623 participants evaluates alternative treatments for infectious syphilis. The analysis…
A new review suggests doxycycline may cure syphilis when penicillin isn't an option, but the evidence is weak.
Sep 3, 2026
Adequate treatment for maternal syphilis reduces stillbirth odds by 84% in pregnant women
Infectious Disease Meta-analysis
Adequate treatment for maternal syphilis reduces stillbirth odds by 84% in pregnant women Adequate Treatment for Syphilis Linked to Lower Stillbirth Rates
This meta-analysis of global data indicates that treatment adequacy for maternal syphilis is a primary driver of reduced stillbirth risk. Wh…
Adequate treatment for syphilis in pregnant women is linked to a significant reduction in stillbirth rates compared to inadequate treatment.
Sep 3, 2026
TORCH seroprevalence 32.5% in Malaysia; CMV highest, screening urged
Pediatrics Meta-analysis
TORCH seroprevalence 32.5% in Malaysia; CMV highest, screening urged TORCH infections found in 32.5% of Malaysian pregnant women and infants
This meta-analysis of 19 reports estimates a 32.5% overall seroprevalence of TORCH infections among pregnant women and infants in Malaysia, …
A meta-analysis finds 32.5% of pregnant women and infants in Malaysia have been exposed to TORCH infections, with CMV most common.
Aug 24, 2026
Mucocutaneous manifestations serve as diagnostic indicators for various systemic diseases and paraneoplastic syndromes
Rheumatology Guideline
Mucocutaneous manifestations serve as diagnostic indicators for various systemic diseases and paraneoplastic syndromes Skin and Mouth Signs May Signal Serious Internal Diseases
This narrative review synthesizes the clinical significance of mucocutaneous signs as indicators for conditions including SLE, dermatomyosit…
Certain skin and mouth changes can serve as important clues for doctors to identify underlying conditions like lupus, infections, and metabo…
Frontiers Aug 16, 2026
4CMenB vaccine did not reduce infection rates compared to placebo in MSM population
Infectious Disease RCT
4CMenB vaccine did not reduce infection rates compared to placebo in MSM population Trial shows 4CMenB vaccine does not prevent gonorrhea or syphilis
This randomized controlled trial evaluated 4CMenB in 587 men who have sex with men (MSM) recently diagnosed with gonorrhea or infectious syp…
A large trial found that a new vaccine did not reduce the rates of gonorrhea or syphilis infections in men at high risk for these conditions…
Jul 23, 2026
Syphilis prevalence is 5.20-fold higher in low-income countries among forcibly displaced populations
Infectious Disease Meta-analysis
Syphilis prevalence is 5.20-fold higher in low-income countries among forcibly displaced populations High Rates of Syphilis Found Among Displaced Populations
This meta-analysis of 1.1 million test results across 82 reports evaluates the prevalence of syphilis, gonorrhea, chlamydia, and trichomonia…
A large-scale review reveals high rates of syphilis and other infections among refugees, highlighting the need for better screening in these…
Jul 17, 2026
Review analyzes political drivers of PMTCT prioritization in Ghana, Mozambique, and Sudan
Primary Care & Family Medicine Sys. Review
Review analyzes political drivers of PMTCT prioritization in Ghana, Mozambique, and Sudan Strong advocacy networks drive success in ending HIV transmission to babies
This qualitative, cross-country comparative policy analysis reviews documents from Ghana, Mozambique, and Sudan to understand political prio…
United voices and reliable data help nations stop HIV from passing to newborns, but weak leadership blocks progress in some places.
Frontiers May 11, 2026
Genomic analysis of 1,707 syphilis genomes reveals lineage-specific diversity and resistance markers across 11 countries
Infectious Disease
Genomic analysis of 1,707 syphilis genomes reveals lineage-specific diversity and resistance markers across 11 countries Syphilis Strains Differ Globally And This Changes Vaccine Plans
This research article presents a genomic analysis of 1,707 Treponema pallidum genomes, including 298 new sequences from 11 countries.
New genetic maps reveal syphilis bacteria changes shape by region which impacts vaccine design and drug resistance monitoring efforts global…
medRxiv Apr 29, 2026
CSF Cytokine Panel and Machine Learning for Neurosyphilis Progression Prediction
Allergy & Immunology Cohort
CSF Cytokine Panel and Machine Learning for Neurosyphilis Progression Prediction New Test Could Catch Dangerous Syphilis Complication Early
This observational cohort study evaluated 48 cerebrospinal fluid cytokines in 129 patients with syphilis to distinguish patients from contro…
Imagine getting treated for syphilis — but months later, you start forgetting things, losing balance, or going blind.
Frontiers Apr 22, 2026
Meta-analysis finds doxycycline prophylaxis reduces STI risk in MSM and transgender women
Infectious Disease Meta-analysis
Meta-analysis finds doxycycline prophylaxis reduces STI risk in MSM and transgender women A Common Pill Could Slash Your Risk of Common STIs
A systematic review and meta-analysis of 14 studies in men who have sex with men and transgender women found doxycycline prophylaxis reduced…
A major review of the latest science confirms that a simple antibiotic, taken strategically, offers powerful new protection against chlamydi…
Apr 12, 2026
CDC issues new recommendations for diagnostic tests supporting syphilis diagnosis
Infectious Disease
CDC issues new recommendations for diagnostic tests supporting syphilis diagnosis What's changing in syphilis testing? New CDC recommendations aim to help doctors diagnose
The CDC has published new recommendations for diagnostic tests that can support a diagnosis of syphilis.
New CDC guidelines update how doctors diagnose syphilis to ensure clearer test results and more accurate patient care.
CDC Apr 5, 2026
CDC recommends doxycycline postexposure prophylaxis for high-risk populations to prevent syphilis, chlamydia, and gonorrhea
Infectious Disease
CDC recommends doxycycline postexposure prophylaxis for high-risk populations to prevent syphilis, chlamydia, and gonorrhea CDC now recommends a pill after sex to help prevent common STIs
The CDC has issued clinical guidelines recommending doxycycline postexposure prophylaxis (doxy PEP) for populations at high risk for syphili…
CDC now recommends a single antibiotic pill after sex to help prevent syphilis, chlamydia, and gonorrhea in high-risk groups.
CDC Apr 4, 2026

Research across Treponemal Infections

Related studies from across the Treponemal Infections family.

Half of U.S. congenital syphilis cases linked to gaps in prenatal testing and treatment
Infectious Disease
Half of U.S. congenital syphilis cases linked to gaps in prenatal testing and treatment Half of U.S. congenital syphilis cases linked to gaps in prenatal testing and treatment
An observational analysis of U.S. congenital syphilis cases found that half were associated with gaps in prenatal testing and treatment.
Half of U.S. newborn syphilis cases happen because mothers missed testing or treatment during pregnancy.
CDC Apr 6, 2026
CDC report outlines syphilis testing and treatment roles for providers outside prenatal care
OB/GYN & Women's Health
CDC report outlines syphilis testing and treatment roles for providers outside prenatal care How can doctors outside prenatal care help stop syphilis in newborns?
A CDC Vital Signs report describes how health care providers outside of prenatal care settings can help prevent congenital syphilis in pregn…
Doctors outside prenatal care must test and treat pregnant patients for syphilis to stop deadly newborn infections, as many miss traditional…
CDC Apr 4, 2026

Questions about Syphilis

How do political factors influence syphilis prevention programs in Africa?

Political factors like instability, weak governance, and uneven donor funding can disrupt syphilis prevention in Africa, while strong political commitment and advocacy improve program success.

Full answer →
What new CDC tests can support a diagnosis of syphilis?

The CDC's 2024 recommendations include newer serologic tests (automated treponemal and nontreponemal tests) and molecular tests like NAATs for direct detection of T. pallidum, but no single new test replaces the need for an algorithm.

Full answer →
Can doxycycline help prevent syphilis after a high-risk exposure?

Yes, taking doxycycline within 72 hours after sex can reduce the risk of syphilis by about 77% in men who have sex with men, based on clinical trials.

Full answer →

All Syphilis Articles