1. Is hiv 2 prevalent in the U.S.? What are the chances that someone like me living in the southern United States would catch hiv 2 if they slept with someone of non-African descent? 

2. Does hiv 2 have a longer window period? Can p24 antigen pick up on hiv 2 as well? 

3. Does an hiv test need FDA approval to be legitimate, even if it’s from an accredited laboratory? (I.e. Labcorp, Quest) 

4. Why do most doctors still adhere to a 6 month window period? 

5. Does HIV 2 cause different symptoms to HIV 1? Or faster progression to AIDS? 

6. Do modern HIV 3rd and 4th gen tests pick up on all strains of hiv? 

7.  Is a rapid test definitive at 100 days post exposure? 

8. Can a previously healthy person progress to aids within a year? 

Thank you for your time. 

9. Can antigen production be delayed by coinfections? 

1. HIV2 is very rare in the US. From 1987 through 2017, 364 HIV2 infections were diagnosed and reported, compared with more than 1,700,000 HIV1 infections; and the frequency of HIV2 was no higher in 2010-2017 than it was earlier. Almost all cases continue to occur persons from small parts of Africa and their sex partners. So to answer your direct question, the chance of HIV from sex with a someone not from Africa is zero for all practical purposes.

2,6. The time to a positive antibody test is no different in HIV2 than HIV1. However, p24 antigen detects only HIV1. Therefore, the standard antigen-antibody (AgAb, "4th generation") window period is around 8 weeks for HIV2, compared with 4-6 weeks for HIV1.

3. This depends on your personal definition of "legitimate". 

4. "Most doctors" definitely do not espouse a 6 month window period for HIV testing, whether HIV1 or HIV2. All knowledgeable authorities follow the CDC guidelines, which means 6 weeks for HIV1 (using the AgAb tests) and 8-12 weeks for HIV2.

5. The opposite. HIV2 tends to progress to overt AIDS more slowly than infection with HIV1.

7. The rapid AgAb tests are just as accurate as the lab-based tests, and 100 days is more than sufficient.

8.  Yes, a newly infected person can progress to overt AIDS within a year. But very rarely.

9. There are no medical conditions that delay either antibody or antigen detection with the standard tests.

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

HHH, MD

And yes: a rapid HIV antibody test would detect HIV2 infection at 100 days. But you don't need an additional test, if you had a negative AgAb result at least 8 weeks after the exposure you are concerned about. 

1. Is it true that it is antibody that clears antigen from the blood, and thus never a time where antibody nor antigen are not present? 

2. Have you ever encountered a patient with lots of text book symptoms, who ended up testing negative 100%? Do you believe stress can create symptoms? 

3. Have you ever encountered a patient who took longer than 3 months to show positive on a 3rd or 2nd generation test? 

Thank you doctor. 

2. Yes, we see this all the time. Typical symptoms of acute HIF infection ("textbook symptoms") are extremely common but usually are due to conditions other than HIV. That's why monitoring symptoms after a possible exposure is generally a losing game. Presence of symptoms doesn't mean HIV, usually something else; and absence of symptoms doesn't mean there is no HIV infection. (Response to the stress question below.)

3. This is extremely rare and I've never experienced such a patient. The earliest HIV antibody tests (first and maybe some second generation) once in a while failed to turn positive, but I am unaware of scientifically documented cases with third generation antibody tests or the AgAb (4th gen) tests. In theory, potent immunosuppressive drugs (like high dose corticosteroids or cancer chemotherapy) might delay or prevent antibody production, and there were concerns about this for the earliest HIV antibody tests. However, even then this was very rare, if it occurred at all; and it certainly has not been a problem with the newer tests (i.e. for the last 15-20 years).

Stress and symptoms:  Stress can cause a whole range of body sensations that can include some of the symptoms of acute HIV (i.e. acute retroviral syndrome, or ARS). This can happen as a direct result of stress or, more commonly, because stress and anxiety often magnify or otherwise make people more aware of minor symptoms or entirely normal body sensations that otherwise would be ignored or not even noticed. However, psychological cannot cause truly typical symptoms like fever, enlarged lymph nodes, or skin rash. I'll stress once again that the test results ALWAYS overrule symptoms in judging whether or not someone has HIV (if enough time has passed since exposure):  and I truly mean always, no exceptions known to exist.