01 — The short answer
HIV risk per exposure: the honest answer.
The HIV risk per exposure is usually low for a single act, but it is never zero for condomless anal or vaginal sex, and one encounter can be enough.
The published figures are averages from large studies, and they can’t tell you what happened in your situation. What can change your outcome is acting in time: PEP must start within 72 hours and works best when started as early as possible.
So read the numbers below for context, not as a verdict. If the contact involved real risk, the sensible step is to ask a doctor about PEP today.
02 — The numbers
Estimated odds by type of contact.
The most quoted figures come from the US Centers for Disease Control and Prevention (CDC), based on a 2014 review of many studies by Patel and colleagues.
They describe the average chance of HIV passing on in one act when the partner has HIV and is not on effective treatment.
Estimated HIV risk per exposure by activity
| Activity (no condom, no PrEP) | CDC estimate per 10,000 acts | Roughly |
|---|---|---|
| Receptive anal sex (bottom) | 138 | 1 in 70 |
| Insertive anal sex (top) | 11 | 1 in 900 |
| Receptive vaginal sex | 8 | 1 in 1,250 |
| Insertive vaginal sex | 4 | 1 in 2,500 |
| Sharing needles to inject drugs | 63 | 1 in 160 |
| Giving or receiving oral sex | Low (no reliable figure) | Very rare |
The “roughly” column uses the wording of the CDC’s own HIV Risk Reduction Tool. A needlestick injury from a used needle is a separate situation, covered in our guide to PEP after a needlestick injury.
03 — Why averages mislead
Why one number can’t describe your night.
A per-act figure is a long-run average, a bit like the chance of rain on an average day in a whole year.
Some encounters carry far more risk than the average and some far less. The numbers above also assume your partner definitely has HIV and isn’t on treatment. With a partner of unknown status, the real chance is usually lower, but you cannot know how much lower from the outside.
Can you get HIV from one time?
Yes, it is possible, even though it is uncommon for any single act. “It was only once” is not the same as “it was safe”, yet many people have one condomless encounter and do not get HIV.
That uncertainty is exactly why the HIV risk from one time exposure is a question for a doctor, not a calculator.
04 — What changes the odds
What pushes the risk up or down.
The CDC lists several factors that shift the HIV transmission rate per exposure away from the average in either direction.
What raises or lowers the risk
| Factor | Effect on risk | Why |
|---|---|---|
| Partner’s viral load is high | Higher | More virus in body fluids |
| Partner recently infected (acute HIV) | Higher | Viral levels peak early, often before a diagnosis |
| Another STI, sores or bleeding | Higher | Inflamed or broken skin lets the virus in more easily |
| Condom used correctly | Much lower | Blocks fluid contact |
| You take PrEP as prescribed | Much lower | Medicine already in your body |
| Partner undetectable on treatment | No sexual transmission | U=U |
The last row matters. The San Francisco AIDS Foundation explains that people with HIV who keep a viral load below 200 copies/mL for at least six months do not pass HIV on through sex, a finding backed by large couples studies such as PARTNER.
05 — Oral sex
Oral sex: very low, not a zero.
The HIV risk from oral sex is very low, so low that the CDC gives no reliable per-act number.
The San Francisco AIDS Foundation’s answers to common HIV questions describe oral sex as low risk and say you probably will not get HIV from giving or receiving it. The small risk that exists rises with mouth ulcers, gum disease or a throat infection, and with ejaculation in the mouth.
Doctors rarely offer PEP for oral sex alone. It may be discussed if there was blood, open sores or a partner known to have HIV who isn’t on treatment. Oral sex can still pass on gonorrhoea, chlamydia and syphilis, so a full STI check in Pattaya is often the more useful step.
06 — Massage and touch
Massage, touch and kissing: where HIV can’t go.
HIV from massage is not something you need to worry about: touch, skin-to-skin contact and sweat do not transmit the virus.
HIV passes on through specific fluids, mainly blood, semen and pre-cum, vaginal and rectal fluids, and breast milk, reaching a mucous membrane or broken skin. Intact skin is an effective barrier. The CDC rates touching as extremely low to no risk, with a theoretical risk only when damaged skin meets one of those fluids.
No-risk and low-risk contact
| Contact | HIV risk | Note |
|---|---|---|
| Massage, hugging, hand-holding | None | Skin, sweat and oil don’t carry HIV |
| Hand job or fingering | Extremely low to none | Only a theory with fresh blood on open wounds |
| Closed-mouth kissing | None | Saliva doesn’t transmit HIV |
| Deep kissing | Extremely rare | Only with bleeding in both mouths |
| Shared towels, cups, toilets | None | No route into the body |
If what worries you was limited to this table, PEP is not needed.
07 — What to do
Stop counting, start the clock.
You don’t need to work out your odds; you need to know whether the contact was a real risk and how many hours have passed.
- Check the type of contact. Condomless anal or vaginal sex, a condom that broke or slipped, or shared needles all count as real risk.
- Check the time. Use the 72-hour PEP window to see how long you have left.
- Talk to a doctor today. Call, LINE or WhatsApp us and say it is about PEP.
- Start PEP if advised after a baseline HIV test, then take it daily for 28 days.
If a broken condom brought you here, our step-by-step guide on what to do if a condom breaks covers pregnancy and STI steps too. You can also see what happens at your PEP visit before you come in.
08 — Testing
Testing at the right moment.
A test in the first days after an encounter shows your status before it, not whether that contact passed anything on.
Follow-up tests at around 6 weeks and 3 months give the answer, as explained in our guide to HIV testing in Pattaya. Checking your body for signs rarely helps, because early HIV symptoms after an exposure look like many common illnesses.
If you often find yourself searching these numbers, PrEP in Pattaya can take the guesswork out of future encounters. The HIV numbers for Pattaya show that risk follows the encounter, not the city.
Questions
Your questions, answered briefly.
Written by the HIV PEP Pattaya team, based on CDC and San Francisco AIDS Foundation guidance. Last updated 29 September 2026.
What are the odds of getting HIV from one time?
For one act with a partner who has HIV and isn’t on treatment, CDC estimates range from about 1 in 70 for receptive anal sex to about 1 in 2,500 for insertive vaginal sex. With a partner of unknown status the real chance is usually lower, but it is still worth asking about PEP within 72 hours.
Is HIV risk from oral sex without ejaculation lower?
Yes. Oral sex already carries a very low risk, and no ejaculation in the mouth lowers it further.
Can you get HIV from a massage if you have a cut?
No. Massage oil, sweat and skin contact don’t carry HIV, and a small healing cut on your hand is not a route for infection from touch alone. Only sexual contact or shared needles would change that.
What is the HIV transmission rate per exposure for a needlestick?
CDC figures put it at roughly 23 per 10,000 injuries, or about 0.3%, when the needle carried blood from someone with HIV who isn’t on treatment. Most real needlesticks carry far less; see our guide to PEP after a needlestick injury.
If the risk per act is so low, do I still need PEP?
Possibly. Low on average doesn’t mean low in your case, and PEP only works if started within 72 hours. A doctor will tell you honestly if it isn’t needed.
Pattaya, Thailand
Don’t wait until tomorrow.
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