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HIV risk with certain sexual behaviors
David J Malebranche, MD, MPH posted:

Many of you ask about what are the chances of getting HIV after engaging in certain behaviors. This is hard to do, and its difficult to give you an accurate sense of what your actual risk is, because HIV transmission, because it depends on so many things, including:

1. If your sexual partner, is, in fact, HIV positive
2. If this partner is on HIV meds and viral load is low or "undetectable," the risk is less
3. If either of you has an STD like herpes or syphilis, which can increase risk
4. The exact behavior you did

Not all behaviors are created equal when it comes to putting you at risk for HIV; Here are the most risky to the lowest risk behaviors for HIV transmission, in descending order when one is not using a condom:

1. anal sex when you are receiving - by far the riskiest - and doesn't matter whether you are a man or woman - we all have anuses!!!!
2. vaginal sex - for the woman
3. anal sex when you are giving (being the "top")
4. vaginal sex - for the man
5. oral sex - for the one giving
6. oral sex - for the one receiving

So, in short, if you are not using a condom with someone who is HIV positive and you are HIV negative, #1 is the most risky thing you can do, and # 6 is the least risky. Like I said, the other factors I listed above can play a part in risk as well, and while its not likely that you will get HIV from ONE sexual encounter with a person who is positive or you don't know their status, it has happened - so be careful and take care of yourselves!!!

Remember, when you know the risk with certain behaviors, you can make the decsion for yourself what you are comfortable with doing... especially when you don't know your partner's HIV status.

Andie_WebMD_Staff responded:
This is a great thread that answers many of the questions that our new Community Members and Guests often ask.

You might want to start here to see if some of your questions are answered before posting. If you still have questions that are along these lines, please post your question here.

Or, if you have specific questions that are off topic, please post it as it's own new Discussion to have a better chance of being seen and replied to.

Thanks, Dr. David, for such being such a great resource! We are very fortunate to have you on board with us. Don't you just love him?
sep83 responded:
May i know the average probability of each of the group you mentioned above
georgiagail replied to sep83's response:
The stats we most often use here:

Estimated per-act risk with an infected source and assuming no condom use:

1. receptive anal intercourse - 50 per 10,000 exposures
2. receptive penile- vaginal intercourse - 10 per 10,000 exposures
3. insertive anal intercourse - 6.5 per 10,000 exposures
4. insertive penile-vaginal intercourse - 5 per 10,000 exposures
5. receptive oral intercourse - 1 per 10,000 exposures
6. insertive oral intercourse - .5 per 10,000 exposures.

sep83 replied to georgiagail's response:
Does this probability is a function of viral load or Log of viral load?
Nieciedo replied to sep83's response:
These probabilities are averages, so they assume an average viral load. The higher the actual viral load, the higher the probability of infection; the lower the actual viral load, the lower the probability of infection.

Anyone who is HIV can transmit the virus to another person through the activities described above, but a person who is newly infected (whose viral load is extremely high prior to the equilibrium established by antibody production) is more likely to transmit the virus than a person whose viral load is undetectable due to a healthy lifestyle and medication regimen.

ceceh42 replied to Nieciedo's response:
Does that 10,000 times mean if you had sex with 10,000 people who had HIV that you would be 50 times likely to get it out of 10,000 people who actually have it?
ceceh42 replied to ceceh42's response:
not 50 times likely but that there are so many chances of you getting HIV if you have sex with 10,000 people who have HIV? like 50 of those chances you could get HIV.
scott521 responded:
Does protected oral sex warrent testing if condom did not break and no seman was noticed in the mouth.
Nieciedo replied to scott521's response:
No. Protected sexual encounters are by definition protected and therefore there is no risk.

Nieciedo replied to ceceh42's response:
Think of it this way:

There is a big bin with 10,000 balls. 50 of them are black and 9,950 are white. Receiving uprotected anal intercourse from HIV tops is like drawing a ball blind from the bin. There is an average of 50/10,000 chance of picking a black ball, which means you get infected. You can pick a black ball on the first try, or after 10 tries, or after 100. That is the average risk.

johnpaul55 replied to Nieciedo's response:
Has protected oral and vaginal sex ever resulted in hiv infection?
mmkjhyt responded:
what if a guy had some cum or precm on his finger, then fingered a girl? or what if he kissed her nipples. theoretically.?
brilliantb responded:
Hello, I would be very grateful if someone please could answer this question!
Should a person get tested for HIV if they didnt knew if the other person was hiv positive or not and their penis touched their vagina and anus several times quite strongly but did not went inside nor into vagina nor in anus, they didnt had saliva sharing. Thank you!!!

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