[Question #1128] HIV Oral Receptive and Window Period

85 months ago
Dear Doctor, 

9 weeks ago I had unprotected oral sex (insertive and receptive) with a gay man of unknown status. There was no ejaculation but Im worried I had a healing ulcer in my mouth. It was not raw and open but there and healing. Is this bad news? 

Got vax for Hep A + B and had the following tests done:

18 days urine sample and throat swab for chlymdia and gonnorhea
28 days HIV 4th Gen
33 day HIV 4th Gen and Syphillis 
49 day HIV 4th Gen 

All negative but the 28 day and 49 day were done at a reputable private clinic in Edinburgh, UK where the blood was collected by finger tip instead of from vein. They insisted the test carried out on the blood in the lab was the same. Can I trust these results? 33 day was veinous.

I was told by the nurse that 12 weeks is conclusive for HIV and that I should not have unprotected sex with my wife. Im very confused as to the conflicting information. For example, is it true the CDC considers 4 weeks conclusive now? Also, the EU guidelines and France say 6 weeks. Meanwhile, BASHH and EAGA say that 4 weeks is highly likely to exclude and further testing at EIGHT weeks should only be considered for high risk. The guidelines for PEP in the UK would not recommend PEP for me and estimate a 1 in 166,667 risk of acquiring HIV from a man of unknown status outside London with fellatio and no ejaculation. Thats not a high risk so Im just stressed out because I want to have unprotected sex with my wife again on holiday without giving her HIV. I know syphillis is tricky but in terms of HIV, would you advise that Im okay? 

Thank you so much. 

Edward W. Hook M.D.
85 months ago

Welcome to our Forum.  I will be happy to add my comments to the information you have already gathered.  You are experiencing the consequences of different interpretations of the same data.  I hope that what I am going to explain will not be confusing- here goes.   When companies that manufacture tests for HIV (or other STIs) and seek official governmental approval, there is a negotiation process that takes place to determine how studies evaluating the new tests will be officially interpreted.  For complex statistical reasons, larger (and therefore more time consuming and more expensive), studies are required to show that a new test is more sensitive (i.e. detects HIV earlier) than the  already approved test it is being compared to.  Therefore, for manufacturers, the "path of least resistance" is simply to show that the new test works as well as earlier tests (i.e. performs "equivalently"), even if the new test is actually better.   While the standards and laws vary from nation to nation, the result of the situation I have described means that for governmental approval even highly sensitive, 4th generation test performance is compared to the performance of older 3rd and even 2nd generation HIV tests, resulting in the "official" statements being that results are equivalent and therefore conclusive at 12 weeks after exposure, even if the data show that all infections were actually identified far earlier.  As a result, "official", "approved" package inserts state that even 4th generation HIV tests provide conclusive results at 12 weeks after exposure.  The FACT however is, that I know of no study, nor any expert colleague, who has ever seen even a single person who was not taking anti-HIV medication develop a positive 4th generation test more than 4 weeks after exposure and based on this, we, as well as BASH and EAGA are completely comfortable in telling you that your results with 4th generation tests are entirely reliable at any time more than 4 weeks following an exposure.  Governmental agencies (including the U.S. CDC must agree with their governmental colleagues.  The nurse you spoke with is telling you the "official" recommendation.   In my opinion however, based on many studies and considerable experience, I am entirely comfortable telling you that you are n the clear and there is no reason for you to worry about unprotected sex with your wife at this time. 

As far as syphilis is concerned, things are only slightly more complicated, and if now, 7 weeks after your exposure, your syphilis blood tests are negative, I would not worry about syphilis either.

I hope this explanation if helpful and not confusing.  I would not be worried at all if I were you.  EWH

85 months ago
Dear Dr Hook, 

Thank you for taking the time to explain that so thoroughly and so promptly - it is greatly appreciated. 

I think thats what I needed to hear. With 3 negative, Im for sure okay.

Just for information purposes, is blood collected through a finger prick suitable for these tests? Exposure to the air doesnt kill off the p24 antigen or anything? 

Thank you for all your help. 

Edward W. Hook M.D.
85 months ago

Glad you found my comments helpful. I worried that the topic was a bit complex.

Believe  your finger stick results, they are reliable.  Believe your results, no need for further testing