We're doing the Doxy4STICare study to learn about a medicine called doxycycline and how it can help stop people from getting sexually transmitted infections.

Here's what we want to find out:

• How do you people use this medication? Do they take it like they should? Do they keep coming back to check in with their doctors? We're trying to make it easy for everyone to use this medicine right. We're also looking at how this medicine affects people's health over time. Are there any side effects? Does it really stop infections? This helps us make sure the medicine is safe and works we

• Will bacteria become resistant? Using antibiotics a lot can make some bacteria tough to beat, a problem called resistance. We're checking to see if using this medicine makes resistance more common. It's important because we all need antibiotics to work when we're sick.

• Will we pass resistant bacteria to others? Sometimes, people can pass bacteria to each other. We're studying if the medicine changes this in any way. This helps us understand not just how it affects not just one person, but their partners too.

Doxycycline is a type of antibiotic, which is a medicine used to fight infections caused by bacteria. It belongs to a group of antibiotics called tetracyclines. Doxycycline works by stopping bacteria from growing and multiplying, which helps your body's immune system to fight off the infection more effectively. It has been traditionally used for infections but more recently has been shown to be able to prevent bacterial sexually transmitted infections like chlamydia, syphilis, and maybe gonorrhea.

No! We are looking for those who are prescribed Doxy-PEP as well as those that are not.

• One of our unique questions is can resistant bacteria be passed to people we have sex with?

• Including your partners helps researchers get a fuller picture of how doxycycline post-exposure prophylaxis (Doxy-PEP) impacts not just individuals, but also their networks. This can provide insights into how infections spread within relationships and communities.

• Additionally by examining both participants and their partners, the study can better assess the potential for transmission of bacteria, including those that might be resistant to antibiotics. This information is crucial to understanding the real-world effectiveness of Doxy-PEP in preventing sexually transmitted infections (STIs).

No, your partner does not need to be taking Doxy-PEP to be referred.

• This study is observational only meaning we do not provide any medication as part of the study.

• However, if you need sexual health care or are interested in receiving Doxy-PEP, the NewYork Presbyterian-Columbia sexual health program can provide free or low-cost sexual health services. To schedule an appointment with our clinic, please ask a study team member to have a navigator call you or you can call the warmline at (929) 429-0671.

Nothing! We want to know how people use Doxy-PEP in the real-world and that means stopping and starting. Please continue to complete your weekly surveys so we understand how this medication gets used.

• Stick2PrEP was focused on HIV prevention and HIV-PrEP.

• Stick2Prevent focuses on overall STI prevention.

Speak with your provider, coordinator, or a member of the study team today!

• Nasal (nose) Swabs

• Pharyngeal (throat) Swabs

• Rectal Swabs

• Urine Samples

• Hair samples

• Blood

While we encourage you to provide all sample types you can choose to complete all, some, or none at every visit.

No, these samples are for research purposes only and will not be shared

We will ask you to complete surveys weekly for up to two years, but ultimately it is up to you. You can let us know at any time if you would like to stop the study.

No! You will continue to receive the highest level of sexual health care from the New York Presbyterian-Columbia sexual health program regardless of if you decide to participate in the study.