About STIs + Risks + Risk Management
Sexual health isn’t about eliminating risk — it’s about understanding it, reducing it where possible, and responding early when things happen. PrEP, vaccines, Doxy-PEP, testing, and awareness work best together, not in isolation.
This overview is biased towards queer communities (cis, trans+, and everything else) and people who have sex with people where at least one partner has a penis. This guide is intended to support informed, sex-positive decision-making. It is not a substitute for individualized medical advice.
All the STIs
This list includes both classic STIs and infections that are more common in sexual networks due to close or intimate contact.
- Hepatitis A
- Hepatitis B
- Hepatitis C
- HIV
- HPV
- MPOX
- Syphilis
- Gonorrhea (Neisseria gonorrhoeae)
- Chlamydia (Chlamydia trachomatis)
- Herpes Simplex Virus (HSV-1 and HSV-2)
- Trichomoniasis
STI risk mitigation
Risk mitigation: Pre-Exposure
Vaccination
Anyone¹ who expects to be sexually active with multiple partners should strongly consider completing the full vaccine series for the following vaccines:
- Hepatitis A²
- Hepatitis B²
- HPV³
- MPOX⁴
1: Assuming no existing pre-conditions or other risks
2: For HepA/HepB, they may suggest testing your titers to see if your childhood vaccines are still effective. They most likely need a boost. I did test mine, but I didn’t wait before scheduling.
3: If you are young enough you may already have this. There is no routine blood test to determine current HPV status; vaccination is still recommended even with prior exposure. If you are 46 or older, you may have to find a non-traditional source for this vaccine, as the current FDA guidelines still only go up to age 45. I was able to obtain it via a regional queer community health clinic.
4: While this is not technically an STI, it is currently a higher risk particularly in close-contact situations often found in MSM networks.
PrEP for HIV⁵
PrEP (pre-exposure prophylaxis) is a preventive medication that, when taken correctly, reduces the risk of acquiring HIV through sex by about 99%, even without condom use.
In real-world studies, people who take PrEP consistently have HIV risk so low that new infections are extraordinarily rare. It is widely regarded as one of the most important biomedical breakthroughs in HIV prevention since antiretroviral therapy itself (Though it is important to remember it does not prevent other STIs).
5: One additional thing to note. I do not wish to contract HIV. I am in no way going to take high-risk actions that knowingly put me at risk. AND, I have had to really learn and constantly remind myself that HIV/AIDS in 2026 is a manageable chronic disease, not a death sentence. I grew up in the 80s. I had a friend who died of AIDS-related complications from a blood transfusion in elementary school. My uncle lived in San Fran through the height of the epidemic. This is a deeply ingrained mindset for myself and many others who grew up during this era. If this is you, it is something to be aware of and work to unpack and learn the new reality so you can make more well-informed decisions based on data, not out-of-date fears.
Safe sex practices + exposure awareness
In addition to biomedical prevention tools like vaccinations, PrEP and Doxy-PEP, there are practical, in-the-moment strategies that can meaningfully reduce risk during sex. These approaches work best when treated as layers — flexible tools you can use selectively based on context, partners, and what feels right in a given encounter.
And just to restate - No prevention strategy eliminates all risk; certainty is not the goal, the goal is meaningful risk reduction combined with early detection.
Condoms
Condoms remain one of the most effective tools for reducing the transmission of HIV and many other STIs during penetrative sex. While they are not perfect and don’t cover every type of exposure, they still provide strong protection, especially for anal sex where they dramatically reduce HIV, gonorrhea, and chlamydia transmission.
- Highly effective at reducing HIV risk when used correctly
- Strong protection against gonorrhea and chlamydia during anal sex
- Less effective for STIs spread through skin-to-skin contact (e.g., syphilis, HSV)
- Offer no protection for oral sex unless used for that purpose
- Breakage, slippage, or delayed application are common real-world failure modes
- Can be combined with PrEP or Doxy-PEP for layered protection rather than treated as all-or-nothing
Barriers + other practices
Barriers beyond condoms can reduce exposure in specific contexts, especially for oral sex and activities involving mucosal or skin contact. These are often underused, but they can be helpful tools when they fit the moment.
- Dental dams or cut condoms can reduce risk during oral-anal contact (rimming)
- Gloves can reduce risk during fingering, fisting, or toy use, especially across partners
- Condoms on shared toys reduce transmission between partners or between sites
- Cleaning toys between partners or sites further reduces transmission risk
- Barriers are most useful when there is visible irritation, sores, or bleeding
- Like condoms, barriers are situational tools — not a requirement for every encounter
Awareness
Exposure awareness is about recognizing higher-risk situations and visible signs of infection, not about policing bodies or demanding certainty. It’s a harm-reduction skill that improves with familiarity and experience.
- Learn what actively shedding herpes lesions commonly look like (clusters of blisters, open sores, scabbing)
- Be cautious with visible sores, ulcers, rashes, or unexplained irritation on genitals, anus, or mouth
- Notice bleeding, raw skin, or trauma, which can increase transmission risk for multiple infections
- Pay attention to symptoms like sore throat, rectal pain, discharge, or burning — even if mild
- Remember that many STIs are asymptomatic, especially in the throat and rectum
- Use awareness to inform choices (positions, activities, barriers, or post-exposure options), not to assign blame
- Remember that awareness can reduce risk, but it can’t replace testing or prevention tools, since many infections show no visible signs
Risk mitigation: Post-Exposure
Doxy-PEP
Doxy-PEP (doxycycline post-exposure prophylaxis) is an after-sex antibiotic⁶ strategy that significantly reduces the risk of acquiring syphilis and chlamydia, and partially reduces gonorrhea, when taken within 24–72 hours of exposure. Large clinical trials show reductions of roughly 70–90% for syphilis and chlamydia in people at higher risk. For many trans and queer people, Doxy-PEP adds a powerful new layer of control and peace of mind without requiring changes to desire, partners, or pleasure.
People use Doxy-PEP in different ways depending on context⁷: as a backup after condom failure, or intentionally after higher-risk experiences like group sex or anonymous encounters. Rather than requiring perfect behavior, it offers flexibility — a way to reduce STI risk while still saying yes to pleasure, spontaneity, and connection. Used thoughtfully, it complements other prevention strategies instead of replacing them.
6: Doxy-PEP does not prevent viral STIs like HIV, HSV, or HPV.
7: Doxy-PEP can be controversial in some settings due to concerns about antibiotic resistance and microbiome effects, which is why most guidance emphasizes selective, situational use rather than daily or overly-frequent dosing.
STI Testing
We should all normalize comprehensive STI testing. Talk about your tests. Keep a copy of your latest test results on your phone. Offer to share with partners. Make it just normal⁸!
The general recommendation for everyone who is or expects to possibly be sexually active is testing every three months. If you are very active and have frequent new partners or higher-risk encounters, every month or six weeks is very common and reasonable.
Comprehensive testing means blood tests plus site-specific swabs (throat, rectum, urine) based on how you have sex.
8: Even if you are not currently sexually active, just do it. If you haven’t had a test in 12 months and I ask to see your results, depending on the context, I may or may not believe you when you say you haven’t been active! Make it safe and comfortable and easy for everyone to get tested and talk about your tests.
Real-world risks - prevalence + transmission
To get real-world risk, we want to multiply:
IMPORTANT
RW1. Probability partner is infected × RW2. Per-act transmission probability × RW3. Risk mitigation steps
RW4. Real-world risk
Here we are going to focus on the STIs where there is not an effective pre-exposure action we can take. E.g., PrEP is as close to 100% effective with HIV, so we won’t cover it here.
In public health and epidemiology, MSM stands for “men who have sex with men.” It is a behavioral category, not an identity, and includes anyone who has sex with men regardless of how they identify (gay, bi, straight, trans, nonbinary, etc.).
Although these numbers come from MSM data, they are still helpful for building intuition about risk. STI prevalence tracks sexual behavior and networks more closely than identity, and many trans and nonbinary people share overlapping patterns of exposure. The exact percentages may shift, but the framework for thinking about risk does not.
RW1. Probability partner is infected (background prevalence in MSM network)
Below are realistic background prevalence ranges for MSM in the U.S. and similar high-income countries, stratified into low / medium / high prevalence networks. These are point prevalence (what fraction of potential partners are infected at a given moment), not lifetime risk.
Syphilis (Early / Infectious Stages)
| Network | Background prevalence |
|---|---|
| Low | ~0.5–1% |
| Med | ~2–4% |
| High | ~5–10% |
Notes
- Syphilis prevalence is highly clustered.
- In dense urban MSM sexual networks, 5–8% active syphilis is plausible
- Risk is non-linear: one sex party ≠ one random partner.
Gonorrhea (Any site)
| Network | Background prevalence |
|---|---|
| Low | ~5% |
| Med | ~10–15% |
| High | ~20–30% |
Site nuance
- Pharyngeal GC often drives transmission and is frequently asymptomatic.
- In some PrEP cohorts, 1 in 4 men had GC at at least one site at screening.
Chlamydia (Any site)
| Network | Background prevalence |
|---|---|
| Low | ~3–5% |
| Med | ~8–12% |
| High | ~15–20% |
Notes
- Rectal chlamydia is especially common and often silent.
- Coinfection with GC is common.
HSV-1 (oral / genital)
| Network | Prevalence |
|---|---|
| Low | ~40% |
| Med | ~60% |
| High | ~70–80% |
HSV-2 (genital / anal)
| Network | Prevalence |
|---|---|
| Low | ~10–15% |
| Med | ~20–30% |
| High | ~35–45% |
Critical nuance
- These are seroprevalence, not active shedding rates.
- Only ~10–20% of HSV-positive people are shedding virus on a given day.
- HSV risk is therefore frequent exposure × low per-day transmission, rather than rare exposure × high risk.
Trichomoniasis (in MSM)
| Network | Background prevalence |
|---|---|
| Low | <0.5% |
| Med | ~1% |
| High | ~2–3% |
Notes
- Trich is uncommon in MSM sexual networks.
- When it occurs, it’s usually via bridging with heterosexual networks.
RW2. Per-act transmission probability + RW3. Risk mitigation steps
Summary of per-act transmission risks assuming exposure to a partner who is actively infected at the relevant site.⁹
In other words, “If the partner has the infection, what is the chance it transmits per act, and how much do condoms / Doxy-PEP reduce that chance?”
| Infection | No Protection | Condoms | Doxy-PEP | Condoms + Doxy-PEP |
|---|---|---|---|---|
| Syphilis | 1–3% per act | ↓ ~50% | ↓ ~70–80% | ↓ ~85–90% |
| Gonorrhea | 10–20% anal receptive | ↓ ~80% anal, minimal oral | ↓ ~50% | ↓ ~85–90% anal; ~50–60% oral |
| Chlamydia | 5–15% anal receptive | ↓ ~80% anal | ↓ ~70–90% | ↓ ~95%+ |
| HSV-1/2 | 1–2% per act (if shedding) | ↓ ~30–50% | No effect | ↓ ~30–50% |
| Trichomonas | Very low | ↓ ~80% | No effect | ↓ ~80% |
| 9: Estimates vary by site, sexual role, and local resistance patterns |
RW4. Real-world risks + decisions
As noted at the top, sexual health isn’t about eliminating risk — it’s about understanding it, reducing it where possible, and responding early when things happen.
With that in mind, these are some of the decisions that I have made regarding the risks I have accepted. Note that this is not advice for YOU, or judgement about any different decisions you may choose to make. There are many variables we all need to consider, including our personal situations, risk tolerances, and accountability to others.
For example, when I initially became sexually active with new male partners, it was within the bounds of an Ethical Non-Monogamy (ENM) agreement with my long-term partner who agreed to me experimenting. She was extremely risk averse to any STI exposure, and as we were also still sexually active together, I had to make decisions that took her risk tolerance into consideration, as well. For example, I chose to not use condoms or other barriers for oral contact, I also committed that upon any such contact, I would always take Doxy-PEP. As an IBS-D sufferer, taking antibiotics is a risk for flare up, but it was the trade off for not using a dental dam or condom.
Below are where I currently am with regards to the decisions I have made. These are in the context or assumption of “hook-up” sex, not any sort of longer-term relationship, though even that would be unlikely to change anything in the near term, as I do not anticipate being in a monogamous relationship in the future.
Oral sex (giver + receiver)
- I do not use barriers (condoms, dams) by default. There are some risks, but they can be mostly controlled with observation, testing, and post-exposure tools
- I very directly discussed this with my PCP and my dedicated STI / PrEP Nurse Practitioner and they had no issues with that assessment
Anal sex (penetrative + receptive)
- I have always used condoms for all encounters to date
- Once I am only responsible for my own risk, and not also my pending-ex-partner’s, I will likely consider not using a condom in some contexts. I can’t yet say what those are or when they will feel worth the increased risk until I am able to experiment more
Vaginal sex (penetrative)
- I will use condoms for any casual encounters
- In addition to STI risk, the risk of pregnancy makes this an actually HIGHER risk activity (to me) than anal sex
Now what?
Ultimately, sexual health decisions are personal, contextual, and dynamic. What matters most is understanding the tools available, the risks they meaningfully reduce, and the values guiding your choices.
Now, go get some. 🍑🍆