[Question #7092] Is there a Risk?

7 months ago
Hi Doctor,

So a couple of weeks ago,I for the first time went to a csw. We engaged in unprotected oral (mouth of penis) and protected vaginal sex. I am sure that the condom did not fail during the vaginal sex. However, being my first time I have become anxious over HIV and other STDs that i may have contracted during this event, and hence since this event have not had any sexual exposure. Over the last few days i have gone through this forum and others and have read that unprotected oral is not considered a risk and if penetrating sex is protected that too is risk free.

Questions:
Am I overthinking this out of proportion given the above?
Has there been a case of HIV transmission from unprotected oral specifically mouth to penis?
Do i require HIV testing?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
7 months ago
Welcome to the forum. Thanks for your confidence in our services -- and also thanks for reviewing other questions similar to your own.

The exposures you describe are very low risk for HIV and other STDs, but not zero risk. You cannot have sex with no risk of STD -- the risk can be markedly reduced but not eliminated.

We have said repeatedly and it remains my beiief that there have been no scientifically proved cases of HIV transmission by fellatio (oral-penile contact) from mouth to penis. That doesn't mean it can't occur, and some infected people believe that's how they acquired the infection. Based on those reports, several years ago CDC calculated a possible risk of 1 in 20,000 for the penile partner, if the oral partner had HIV. That's equivalent to receiving BJs by infected partners once daily for 55 years before transmission might be likely. The condom protected vaginal sex probably was higher risk than the oral event, but still extremely low. And the large majority of CSWs don't have HIV. 

Do you "require" HIV testing? No, not from a medical or risk standpoint. However, many people sufficiently nervous to come to a forum like this are more reassured by negative test results than by professional opinion, no matter how expert and science-based the advice might be. (We don't take it personally!) If you're going to lie awake at night worrying about the possibility, you might want to be tested because of the reassurance you would experience from the negative result. If somehow I were in your situation, I wouldn't do it -- but you're the only one who can make that decision.

I hope this information is helpful. Let me know if anything isn't clear.

HHH, MD
---
7 months ago
Thanks doctor for the prompt reply.

.Would you be able to say on the probability of it being a negative result? Has there ever been a case of negative turning positive if no new exposure occurs.
7 months ago
sorry i meant the probability of it being a positive result given the incident..
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
7 months ago
Here's one way to calculate the risk. Chance your CSW partner had HIV, let's say 1% (it's probably lower than that). If a woman has untreated HIV, the average transmission risk for a single episode of unprotected vaginal sex is around 1 in 2,500. Condoms probably are around 99% effective in preventing transmission by vaginal sex. Using these figures, your risk is something like 0.01 x 0.0004 x 0.01 = 0.00000004. That's 4 in 10 million, or 1 in 2.5 million. As discussed above, the oral sex would be 0.01 x 0.00005 = 0.0000005, around 1 chance in 2 million.

So overall, maybe 1 in a million, tops. Which should be viewed as zero for all practical purposes. 

Positive HIV test with no exposure? Of course this isn't possible. However, once in a long while, people have been exposed without knowing it. This is why CDC recommends that every adult in the US be tested for HIV at least once, regardless of known risk factors.
---