Syphilis, Gonorrhea, Chlamydia
Conditions
Interventions
Standard Care Group:Receive standard prevention services provided in Guangdong Province (including free condoms and standard sexually transmitted infection education materials), without doxycycline.
Event-Driven Doxy-PEP Group:Oral doxycycline 200 mg within 72 hours after unprotected sexual exposure (one dose per exposure, maximum dose not exceeding 200 mg over 3 days).
Fixed-Interval Doxy-PEP Group:Oral doxycycline 200 mg once weekly at a fixed time, regardless of sexual activity (once per week).
Sponsors
Dematology Hospital of Southern Medical University
Eligibility
Sex/Gender
Female
Age
18 Years to No maximum
Inclusion criteria
Inclusion criteria: 1. Age >=18 years; 2. Assigned female sex at birth and identify as a woman; 3. Reported engaging in vaginal and/or oral commercial sex in the past 30 days; 4. Able to complete the 12-month follow-up schedule;
Exclusion criteria
Exclusion criteria: 1. Current pregnancy or breastfeeding; 2. Allergy to doxycycline or tetracyclines; 3. Ongoing doxycycline use for other clinical indications (e.g., acne treatment); 4. Current use of medications with known interactions with doxycycline (e.g., retinoids, barbiturates, carbamazepine, phenytoin, warfarin); 5. Unwilling to undergo sexually transmitted infection (STI) testing; 6. Any medical or psychiatric condition that would interfere with participation;
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Time to first bacterial sexually transmitted infection (composite endpoint: syphilis, gonorrhea, chlamydia) during 12-month follow-up;Safety outcomes (including adverse events, serious adverse events, drug-related adverse reactions); | — |
Secondary
| Measure | Time frame |
|---|---|
| Time to first occurrence of syphilis, gonorrhea, or chlamydia during 12-month follow-up;Frequency of high-risk sexual behaviors (e.g., condom use frequency, number of sexual partners);Self-reported doxycycline use (adherence);Proportion of adverse events attributable to doxycycline use;Antimicrobial resistance (AMR) prevalence in Neisseria gonorrhoeae and Chlamydia trachomatis (including resistance percentages to doxycycline, azithromycin, ceftriaxone, ciprofloxacin, streptomycin, and penicillin; percentage carrying AMR genes);Doxycycline exposure level;Economic evaluation (total cost, per-person cost, cost per STI diagnosis, incremental cost-effectiveness ratio); | — |
Countries
China
Contacts
Public ContactWang Cheng
Southern Medical University Hospital of Dermatology (Guangdong Provincial Hospital of Dermatology
Outcome results
None listed