[Question #12427] HIV-2 concern

7 months ago

Hello Doctor,

HIV-2 has very low replication rate and 1/3 infected patients has undetected viral load. Is there a high chance that the body does not produce enough antibodies at the beginning or in chronic infection there is no on-going antibody production for detection?

7 months ago

I have this question because I have many risky behaviour (unprotected vaginal sex with different women) from 2005-2010. I have many tests done which probably ruled out HIV-1 but not HIV-2.

What I concern is the long chronic latent period with very low viral replication rate in the effect of on-going antibody production, that may lead to the misdiagnosis of HIV-2.

H. Hunter Handsfield, MD

7 months ago

Welcome to the forum. Thank you for this question.

I have the feeling you have delved deeply into online information on HIV2 -- but you have apparently missed some key facts. First, the standard HIV tests detect HIV2; there are almost no false negative test results. If your tests have included the standard antigen-antibody (AbAb, 4th generation) blood tests, the negative results are reliable, assuming testing was done at least 6 weeks after the last possible exposure. And if you've had any PCR/RNA tests, they likely would have detected HIV2 as well. These tests now are routine in many US labs, probably most of them. Until the last year or two, these tests detected only HIV1, but more recently some of them detect HIV2 RNA in addition to HIV1. You could check back with the lab(s) where your tests were done. Or if not done before now, you could have such a test at this time.

And I don't fully agree with the premises of your question; I think you must have misunderstood some of the stuff you have found in your research. I am unaware of any reports that the antibody levels produced to HIV2 ever are low enough to not be detected by the standard antibody tests (or by the AgAb tests); and it definitely is false that "in chronic infection there is no on-going antibody production for detection." Whether or not they may sometimes be lower than usual antibody levels to HIV1, all infected persons have levels easily detected by standard tests.

Finally, HIV2 is exceedingly rare in the US and most industrialized countries. And almost all those are in people infected in Africa where HIV2 is endemic, or in their regular sex partners (spouses, etc). And regardless of HIV type, your sexual history doesn't raise any special concern. Almost nobody with "unprotected vaginal sex with different women from 2005-2010" has HIV of either type.

Perhaps I will have further comments if you would like to say more about the specific tests you had and when. But based on what you have said here, I am very confident you do not have HIV2.

HHH, MD

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7 months ago

Dear doctor,

Thank you for your response!

I have done multiple standard lab Ag/Ab Combo and HIV-1 PCR RNA over the years from 2013-2024, and I understand that the combo test looks for the antibodies as well. Yet, the rna only looks for HIV-1. And I know there is HIV-2 rna test but this cannot rule out HIV-2 infection because 30-40% HIV-2 infected patients (untreated) have undetectable viral load.

I know HIV-2 is rare but it may be underestimated in certain places like China which globalisation makes transmission more likely.

Why I concern is that the study of HIV-2 is not enough infection, diagnosis, and disease progress is not well understood.

For example, HIV-2 can have disease progression to AIDS even if with undetectable viral load.

For my concern: I am not sure the standard diagnosis guidelines can apply to HIV-2 infection. e.g. P24 only for HIV-1, and the HIV-2 antibodies on-going production may not be high enough for detection (due to very low HIV-2 replication), and 30-40% HIV-2 infected patients with undetectable viral load.

The whole picture of HIV-2 infection is tricky and the uncertainties make me worry about the validity of standard HIV tests in the detection of HIV-2 infection.

H. Hunter Handsfield, MD

7 months ago

Hmm.... I'm debating with myself over a diplomatic reply or less diplomatic in response to these comments. I've chosen the latter. They suggest you didn't read, didn't understand, or maybe just didn't believe my comments. Was there a problem with "First, the standard HIV tests detect HIV2; there are almost no false negative test results"? And what about many of the current "PCR/RNA tests...detect HIV2 RNA in addition to HIV1." The notion that a high proportion of HIV2 infected persons have no detectable HIV RNA in their blood is wrong. For you to have HIV2, several exceedingly unlikely possibilities would all have to go the wrong way: 1) Little or no risk of any HIV infection from the sexual exposures you have described. 2) That you acquired the type of HIV that accounts for well under one in a thousand HIV infections in the US. 3) That you had atypically negative results and several HIV tests that normally detect HIV2. And 4) that you have remained outwardly healthy months or several years since being infected. Sheesh.

You've clearly read a lot about HIV2, and in some respects you might know more than I do. However, to my knowledge there has never been a documented case of HIV2 that was not detected with the tests you had. I don't accept that HIV2 infection is as "tricky" as you have come to believe. I remain confident you do not have it -- especially after the near zero risk sexual lifestyle you have described. But you are free to believe what you want.

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7 months ago

Sorry Doctor,

I did read and understand all your comments.

Maybe I misled you. That’s not zero risk. I mean I’m a man have unprotected penetrative vaginal sex with different women over the years I mentioned.

And for the HIV tests, whether they are antibodies or viral tests, I believe that they can detect them if they PRESENT in the blood samples.

But in the case of HIV-2, virus are not necessarily present in the blood (even in untreated patients), so RNA test cannot rule out HIV-2 infection.

And for antibody test, I am just have question about the level of HIV-2 antibodies to be adequately present to be detected by the standard HIV 1/2 test in the course of HIV-2 infection as the replication rate of HIV-2 is very low.

You may take a look of the following paper if you have time:

https://pubmed.ncbi.nlm.nih.gov/10667898/

H. Hunter Handsfield, MD

7 months ago

That case is irrelevant. The opening line is that the reportedly infected persons were "seronegative, but culture and proviral HIV-2 DNA positive were found". (Probably DNA is a typo or misunderstanding versus RNA.)

You're being argumentative, but this discussion isn't a debate. You have ignored my observation about the multiple unlikely possibilities that would all have to break the wrong way. You came here for our professional evaluation and advice. Accept it or not, that's not my problem -- but there is nothing more to say.

That completes the two follow-up comments and replies included with each question and so ends this thread. Please do not be tempted to start a new thread to continue this discussion or ask again about this situation. Any such attempt will be dented without reply and without refund of the posting fee. Thanks for your understanding. Best wishes.

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