Chlamydia Infections, Gonorrhea, HIV Infections, Sexually Transmitted Diseases, Syphilis
Conditions
Brief summary
The goal of this clinical trial is to learn if doxycycline post-exposure prophylaxis (doxy-PEP) can help prevent bacterial sexually transmitted infections (STIs) among sexual and gender minorities in Rio de Janeiro, Brazil, including men who have sex with men, transgender women, and travestis who are living with HIV or using HIV pre-exposure prophylaxis (PrEP). Bacterial STIs such as syphilis, gonorrhea, and chlamydia remain common in these populations, even with existing prevention strategies. This study aims to answer the following questions: whether doxy-PEP can reduce the number of new STIs, whether it is safe and well tolerated, whether participants use it as recommended, and whether its use may contribute to antibiotic resistance or changes in the body's natural bacteria. Doxy-PEP involves taking a dose of doxycycline, an antibiotic, shortly after sexual activity to reduce the risk of acquiring STIs. Participants will first receive information and counseling about doxy-PEP, including its possible benefits and risks, and will then choose whether or not to use this prevention strategy. Those who choose to use doxy-PEP will take doxycycline after sex as instructed and will be followed for up to 48 weeks, with clinic visits approximately every three months. During these visits, participants will be tested for STIs, monitored for side effects, and asked about medication use, sexual health, and overall well-being. Researchers will collect information on new STI diagnoses, safety, and how consistently participants use doxy-PEP. The study will also explore participants' experiences and perceptions of this strategy. The results of this study will help determine whether doxy-PEP is a practical and acceptable approach for STI prevention in Brazil and may inform future public health strategies.
Interventions
DRUGDoxycycline
Doxycycline 200 mg taken orally within 72 hours after sexual activity, not exceeding one dose per 24 hours and a maximum of three doses per week.
Sponsors
Oswaldo Cruz Foundation
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
This is an open-label, single-group, pilot implementation study evaluating doxycycline post-exposure prophylaxis (doxy-PEP) for the prevention of bacterial sexually transmitted infections. All eligible participants receive counseling and are offered the option to initiate doxy-PEP. Participants who choose to initiate doxy-PEP are followed prospectively for up to 48 weeks, with regular clinical and laboratory assessments, including testing for sexually transmitted infections, safety monitoring, and adherence evaluation. Participants who initially decline doxy-PEP may opt to initiate it at any time during the study. The study aims to assess feasibility, acceptability, safety, adherence, and impact on STI incidence and antimicrobial resistance in a real-world setting.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Individuals assigned male at birth (cisgender or transgender men), transgender women, or travestis who have sex with men * Age ≥18 years * Living with HIV or currently using HIV pre-exposure prophylaxis (PrEP) for at least 6 months * History of at least one bacterial sexually transmitted infection (chlamydia, gonorrhea, or syphilis) in the past 12 months (laboratory-confirmed or self-reported) * Willing and able to provide informed consent
Exclusion criteria
* Known allergy or hypersensitivity to doxycycline or other tetracycline-class antibiotics * Current use of medications that may significantly interact with doxycycline or are contraindicated, including systemic retinoids, barbiturates, carbamazepine, or phenytoin
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of bacterial sexually transmitted infections (STIs) | Up to 48 weeks | Cumulative incidence of laboratory-confirmed symptomatic and asymptomatic bacterial STIs (syphilis, gonorrhea, and chlamydia). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of symptomatic and asymptomatic bacterial STIs | Up to 48 weeks. | Cumulative incidence of laboratory-confirmed symptomatic and asymptomatic bacterial STIs (syphilis, gonorrhea, and chlamydia). |
| Incidence of specific STIs (chlamydia, gonorrhea, and syphilis) | Up to 48 weeks | Cumulative incidence of each STI (chlamydia, gonorrhea, and syphilis), including symptomatic and asymptomatic cases. |
| Antimicrobial resistance in Neisseria gonorrhoeae | Baseline and up to 48 weeks | Proportion of Neisseria gonorrhoeae isolates with resistance to tetracycline and other relevant antibiotics over time. |
| Colonization with antimicrobial-resistant bacteria | Baseline and week 48 | Proportion of participants colonized with methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL)-producing enterobacteria. |
| Adverse events | From enrollment to 48 weeks | Occurrence of adverse events (AEs), including serious adverse events (SAEs), grade 3 or 4 AEs, and AEs leading to discontinuation of doxy-PEP. |
| Adherence to doxy-PEP | Up to 48 weeks | Adherence measured by self-reported coverage of sexual exposures with doxy-PEP and by doxycycline levels in hair samples. |
| Uptake of doxy-PEP | At enrollment | Proportion of participants who choose to initiate doxy-PEP after counseling. |
| Acceptability of doxy-PEP | Up to 48 weeks | Participant-reported perceptions, experiences, and acceptability of doxy-PEP assessed through questionnaires and qualitative interviews. |
Countries
Brazil
Contacts
CONTACTBeatriz Grinsztejn, PhD
Outcome results
None listed