About this study
Sexually transmitted infections (STIs) are increasing in the United States. Teen and young adult females have a high risk for infections like gonorrhea, chlamydia, and syphilis.
An antibiotic called doxycycline has helped greatly to prevent STIs in men. This medicine is now endorsed by some public health authorities, including the U.S. Centers for Disease Control and Prevention (CDC). But we do not know if it works for females.
This study is needed to find out if doxycycline can help protect females.
The trial compares 3 groups of females who had an STI in the past year:
- 1 group takes a dose of the antibiotic doxycycline within 72 hours after sex without a condom.
- Another group takes a dose once every week.
- A third group receives standard care. This includes regular STI testing, treatment, and counseling.
Participants return for checkups every few months for 1 year. At each visit, they are tested for gonorrhea, chlamydia, and early syphilis. They also answer questions about their health and their use of doxycycline. Samples from the body are collected to help researchers study bacteria and watch for any signs of antibiotic resistance.
Researchers will look at how well doxycycline works compared to standard care. They will also check which way of taking the medicine is easier for people to follow. The study will look for side effects and see if bacteria become resistant to doxycycline.
We want to learn if:
- Doxycycline lowers infection rates
- People will use it as directed
- It causes problems like resistance
These answers will help doctors and health experts decide if doxycycline should be recommended for females at risk for STIs.
Eligibility overview
- Female
- 13–29 years old
- Diagnosed with gonorrhea, chlamydia, and/or early syphilis in the past year
- Had at least 1 episode of condomless oral, vaginal, or anal sex 30 days before screening