[Question #7753] Expert advice needed on a potential exposure

12 days ago

Dear Doctors.


Some background: I’m in my mid-30s, single and live in Hong Kong.


In December 2019 I had a regrettable sexual encounter with a commercial sex worker. She gave me an unprotected blowjob, analingus and we had protected sex with a condom. 29 days later I went to my doctor and took an HIV 1 & 2 Ab & P24 Ag test, a VDRL test (not sure what is included in this), a Chlamydia IgG Antibody test and a Herpes Type 2 IgG (HSV2) test. All tests were drawn from a vein and sent to a lab. All came back negative.

I read sometime later that tests at 28 days are not fully conclusive and my doctor stated testing protocol in Hong Kong for HIV only rules out infection 3 months after exposure. I took another HIV 1 & 2 Ab & P24 Ag test (again from a vein draw) at the 158 day/ 22.5 week mark which came back negative.


My questions:

1.     Are my HIV 1 & 2 Ab & P24 Ag tests conclusive at the 29- and 158-day marks?

2.     Are my other STD tests conclusive? Is any follow-up required?

3.     I have a history of hemorrhoids that can burst and bleed. Would that put me at additional risk?


I had thought I had put this all behind me, but I’ve had intrusive thoughts that I may have put my ex-partner, whom I met after all the tests came back, at risk even though all we did deep kiss, mutually masturbate and dry hump in our underwear.


Your advice is appreciated.

12 days ago
Correction: All relevant tests were drawn from a vein (HIV 1 & 2 Ab & P24 Ag test) but some others required a urine sample. I cannot remember which ones. 
Edward W. Hook M.D.
Edward W. Hook M.D.
11 days ago
Welcome to our Forum and thanks for your questions.  I'll be glad to comment.  The exposures you describe were low risk for STIs and no risk for HIV and long as your condom was worn throughout the encounter.  The reasons for this include:
1. Most commercial sex workers do not have STIs, including HIV.
2.  Even when they do.  Most unprotected exposures do not lead to infection.  In fact there are NO instances in which HIV has been proven to be transmitted through receipt of oral sex or analingus.  Even with unprotected vaginal intercourse with an HIV-infected, untreated partner, more than 99.9% of such exposures do NOT result in transmission of infection.  You wore a condom for your vaginal exposure so this too was a virtually no risk encounter with respect to HIV.    

With regard to your specific questions:

1.     Are my HIV 1 & 2 Ab & P24 Ag tests conclusive at the 29- and 158-day marks?

Your HIV tests were more than 99% conclusive and 29 days and completely conclusive at 158 days.  You can be confident that you were not infected at the encounter you describe. 

2.     Are my other STD tests conclusive? Is any follow-up required?

Your urine tests were probably for gonorrhea and chlamydia while the VDRL is a blood test for syphilis.  Your results are reliable and should be believed.  

3.     I have a history of hemorrhoids that can burst and bleed. Would that put me at additional risk?

No, the presence of rectal hemorrhoids would not change your risk.

I hope this information is helpful and reassuring.  If there are further questions related to this encounter, you can use your up to two follow-ups for clarification.  Take care.  Please don't worry.  EWH

1 hours ago

Thank you Dr. Hook. Your answers have helped. 


After looking through the answers provided to other users, I understand that the testing window for the 4th-gen test is 6 weeks and that the current 3-month window is largely outdated. It’s confusing that the advice varies between doctors and between countries but your expertise in the matter has been reassuring.  


For my future reference:

·      Do you have any further reading or information to share regarding HIV transmission during protected vs. unprotected sex? You mentioned some stats in your response and I would like to better understand

·      What is the window period for a 3rd-gen test drawn from a vein? When can results be considered conclusive?


Thank you. 

Edward W. Hook M.D.
Edward W. Hook M.D.
27 minutes ago
I am pleased that my responses I’ve been helpful to you. Providing you with additional references is challenging. I would strongly warn against going to the Internet and carrying out general Internet searches for additional information. As I believe you have found out, much of what is there is out of date or taken out of context.  Certain websites are reliable although those sites, such as the one for the U. S. CDC need to be viewed carefully in order to make sure the information that you are seeing is not older and potentially out of date. Most of the information we provide on this forum however represents a synthesis of information we have gathered from years of reading the medical literature, attending meetings, and discussions with other experts.   I’m sorry there is not a more concise and well organized source of information.

In general, third generation, antibody only tests for diagnosis of HIV provide conclusive results at eight weeks following exposure.

I hope this additional information is helpful. EWH