Dear Doctor,

I had a sexual encounter with a woman of unknown status about 4 months ago. It was condom protected, and I believe I used the condom correctly. The intercourse was short and lasted for less than 30 seconds. I did not have any symptom. I know that the risk is extremely low for HIV but I still decided to get tested. I got four negative results (4th generation) on day 19, day 36, day 43 and day 88. Since the last test was done more than 12 weeks after exposure, my doctor told me to stop testing, and I know all the knowledgeable doctors would say that my test is conclusive. I think I am close to moving on, I am now working hard to believe the results. 

I have several questions to ask. 

I have read several academic papers on HIV-1 Group P and Group N, and I found that they are readily detectable by current tests (and even earlier tests). I believe that from an antibody perspective, they are detectable, but what about from an antigen perspective? Do Group P and Group N produce similar P24 antigens so that they can surely be detected early?

Previously, both doctors on this site agreed that 4th generation tests are conclusive at 4 weeks. However, recently, the timeframe has been reset to 6 weeks. My understanding is that antigens normally peak at about 25 days, and usually on this day, antigens are already detectable. However, a window period of 6 weeks would imply that it is possible that an infected person does not have detectable antigens until day 42. Are there any actual cases of people turning positive after 4 weeks? What would be the causes of this late production of antigens?

I know that this is rare, but according to a 2010 paper (Spivak et al 2010), there are cases of seronegative patients. They are all symptomatic and had quick progression to AIDS (within 5 months, with the quickest one within 2 months). So I assume that if someone cannot produce detectable antibodies by 6 to 12 weeks, he or she should be already suffering from at least mild symptoms because the viruses replicate rapidly, and there are not enough antibodies to fight the viruses. Do you agree with my assumption?

Are my results conclusive, do I have HIV (I think I know the answer but I would like to have some more reassurance)?

Thank you very much!

Welcome to our Forum. Thanks for your question.  I agree with your doctor, you have now repeatedly proven that you did not acquire HIV from the virtually no risk exposure you have described.  Both your day 43 and 88 test results are conclusive.  

In answer to your specific questions:

1.  The p24 antigen is a widely shared HIV antigen.  Concerns about HIV sub-types being missed by current available tests are misplaced.

2.  Typically over 80% persons who acquire HIV have detectable virus (HIV antigen) by day 8 and virtually all have detectable antigen within three weeks of infection.  We changed our recommendation to when 4th generation tests would be conclusive  from 4 to 6 weeks after colleagues at the CDC unformed us that here were an unquantified, "few" case in which person who had not taken PEP or PrEP had become positive between 4 and 6 weeks.  Neither of us has ever seen such a case and we believe that this is extraordinarily rare but respect our CDC colleagues perspective.  

3.  Your reference to an over 10 year (from time of submission) old paper which has not been widely verified indicates that there MAY be persons who do not produce antibodies to HIV but, were there such persons, we too presume they would be quite sick.  Further, such persons would have VERY high circulating levels of virus and would have positive p24 antigen tests.

4.  As i said in my original response your results are conclusive and having repeated the test twice at more than 6 weeks have been validated.  Be confident that you did not get HIV from the very low risk event you have described.  

I hope that this information is helpful to you.  EWH

.   

Thank you for your very helpful answers. I think I have enough scientific knowledge to believe that I am HIV-negative.

I will keep training myself to be convinced psychologically, and of course, I will be committed to monogamous and safe sex for the rest of my life. 

Please close the thread to avoid further “what if” questions.

Have a nice day!