[Question #7266] Do I need to test for HIV after this exposure?

5 months ago
Hello,

Recently i had protected sex with a CSW and there was some menstrual blood on the condom. When i removed the condom I used a wet wipe. I then used the wipe to clean my penis without thinking. If menstrual blood on the wipe touched my penis, or urethra, could this cause infection?

Also, if i were to test, how accurate would a PCR RNA Qual test be after 14 days?

Thank you
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
5 months ago
Welcome to the forum. Thanks for your confidence in our services.

There is no measurable risk of HIV from the exposure you have described, and no need to test from a medical/risk standpoint. Any "need" is based entirely on your comfort with this assessment. Some people simply are not able to stop worrying based on even the most science-based evidence and no matter how expert the source. (We don't take it personally!) The potential blood exposure makes no difference in risk:  in HIV infected women, the quantity of virus is no higher in blood than genital fluids, and sex with infected women is equally safe (or unsafe) whether or not they are menstruating. So certainly getting some menstrual blood on the outside of a condom is just as risk-free as if no blood were seen. No mear touching of infected fluids (on a wipe, by hands, etc) touching the penis or skin carries any risk of HIV. In fact, the risk of HIV from any single episode of vaginal sex, usually is too low to warrant testing, even without a condom. Rather than running out for a test after every potential exposure, most seaxually active persons generally can just rely on being tested at regular intervals, e.g. every 6-12 months, depending on the context (type of sex worker, known to have HIV or not, and so on).

So as I said, there's no need for testing from a risk perspective:  the chance of HIV from a single exposure of this sort is under one in several million. If you do choose to be tested however, you really needn't spend good money (or public resources) on RNA testing. At 14 days, such tests detect ~95% of new HIV infections, so for 100% proof, you would also need an antigen-antibody (AgAb, 4th generation) test at 6 weeks. I would recommend only an AgAb test at that time.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD
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5 months ago
Hello Dr. Hansfield. 

Thank you for the quick reply! 

All the below makes sense. I just had a couple of follow up questions on the science behind some things in the scenario. 

1. Could blood on a wipe traverse a mucous membrane (penis head) instantly/within seconds, or is prolonged exposure required? 

2. I have heard a lot of people, especially old posts on medhelp talk about the fragility of the virus outside a human host. Would air/oxygen affect the virus' outer shell in a smeared amount (very little) of blood on a condom very quickly, to render it inactive once outside of the vagina? 

3. I have already taken the RNA test - thank you for clarifying accuracy! Why is it that the CDC states the window period can last up to 33 days? Is that for those on supressive medication? From what i understand, the virus replicates very quickly after infecting and should be detectable by an assay with a >40 per ml limit very easily by 14 days. 

Thank you! 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
5 months ago
1. HIV is inherently difficult to transmit. Unprotected vaginal sex with an infected woman carries an average transmission risk of once for every 2,500 events (which is why many spouses of infected persons remain HIV free for months or years). https://pubmed.ncbi.nlm.nih.gov/24809629/ That's because substantial amounts of virus must have intimate contact with particular kinds of cells, typically not on skin or mucosal surfaces. Duration of exposure undoubtedly is important as well, but few data exist. Such quick transit across a mucous membrane probably is exceedingly unlikely, but I cannot say it has never happened.

2. You're right that there's a lot of online noise about HIV survival with drying, air exposure, etc. It's mostly speculative with few useful data. (The negative connotation of "noise" is intentional.) The important point is the virtual absence of transmission with other than intensive, prolonged sexual contact or direct blood exposure. The risk being so low, why worry about the biological reasons? That's why there hasn't been much research:  low priority.

3. Correct, 33 days until 100% reliability of the RNA tests. Nothing in my reply (~95% at 14 days) is inconsistent with that. My understanding is that CDC bases its advice on the main publiction reviewing performance of most HIV tests available at the time https://pubmed.ncbi.nlm.nih.gov/29140890/, which was accompanied by an editorial written by experts at CDC. I'm not enough of an HIV virologist to explain the long tail, i.e. why a small proportion of infected persons take longer to have detectable RNA in blood.
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5 months ago
Thank you again for the reply! My last few round of questions:

1. Would a negative rna and a negative 28 day duo be considered conclusive? In the UK, BASHH guidelines say that you dont need to retest after a 4 week duo test unless the exposure is deemed high risk. However elsewhere it is 6 weeks. 

2. Would the blood on the tissue be deemed a direct exposure or a 'casual' touch to a mucous membrane? To clarify further, it would only have potentially been the blood that could have leaked through the other side of/been absorbed into the wipe, not on the side of the blood itself. 

Also if the blood did not get into the urethra, could it still transmitt? I know for a fact it did not touch my inner foreskin and was absorbed into the wipe. 

3. Someone posted online claiming an RNA test would miss up to 54% of infections 12 days in per a recent CDC study. This seems totally incorrect - or would you know about the study mentioned/any credibity for this? 

4. Why would it be that respected STI clinics clain 99.7% accuracy on the RNA tests? Dr. Tan claims it as conclusive after 12 days. I saw on previous posts on this forum that even Dr. Hook would consider it nearly conclusive after 14 days.

Thank you again! 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
5 months ago
1. I agree with the BASHH guidelines on this. To enlarge on their clarification "unless deemed high risk": of course test performance is identical regardless of risk. But if the chance of infection is, say, 1 in a million, a 99% reliable result drops the odds to 1 in a hundred million, which is zero for all practical purposes. But if the original risk were, say, 1 in 1,000 (say unprotected anal sex with a known infected partner) a 99% reliable result still leaves 1 chance in 100,000 that the test missed a new infection. Same test but different levels of assurance. Hence BASHH (and Dr. Hook and I) would advise another test beyond 6 weeks.

2. Very casual, no risk. And no, HIV cannot be transmitted through intact skin.

3. That estimate is much too high, from all I know. If there is a more recent scientific report, I am unaware of it.

4. The data on time to conclusive results are quite soft, and such advice -- on this forum or elsewhere -- often is based as much on extrapolation from the biology and pathogenesis of HIV infection as on actual data on test results. It's not all that easy to precisely study window periods:  you'd need hundreds of persons with an exactly known date of exposure who then had weekly or even more frequent testing for several weeks. Absent such data, there's a lot of room for interpretation of the required time and advice to persons at risk. Hence the widely variable advice. My personal view is that in the real world, the RNA test probably detects ~95% of infections by 14 days and 98-99% by 21 days (not counting persons taking PrEP or PEP that fails, in which case it could take quite a bit longer).

On a forum like this, whether to advise based on our personal beliefs versus the available data sometimes is uncertain, and our advice may vary depending on the perspectives, anxieties, etc of the questioner. You seem to have an objective, thoughtful perspective, so I've given you a range of possibilities. My or Dr. Hook's replies to others could vary. This is actually a good lesson for forum users in general:  our previous replies always should be interpreted in the context of the question answered and not automatically trasposed to all similar situations.

That completes the two follow-up exchanges included with each question and so ends this thread. I hope the discussion has been helpful.
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