[Question #5706] Shingles and ars together

19 months ago
Dear Dr. 

A month ago I met a girl on an online dating app and we had vaginal sex. I used a condom but at some point, I lost erection and we stopped. 5 min later I realized condom was not on and I asked her what happened. she said it stayed in/on her vagina after. I assume there was most probably an exposure. Since that moment I have been having severe anxiety.


3 day later I start having a sore throat. It was disturbing but wasn't hurting as bad as the sore throat happens with flu/cold. it lasted for about 2-3 weeks 

around 10 days later I had a rash on my chest and arms ( 4-5 pimple on my chest and few on my arm)

3 weeks later I had pain under my chin and it lasted for 2 days. I also had a mild fever for only a day.  I also have a painful spot on my upper thigh, I tried to check if it is a lymph node but it is hard to tell since entire muscle tissue feels like small bumps. 

at day 27 I got tested with 4th gen ab/ag lab test and it came negative. 

I haven't been eating and sleeping well for a month due to severe anxiety and stress and now I have shingles on my back. Big painful burning red patch.

-From my calculations-

only 1% of people in the US have HIV  and only 1 out of 2000 vaginal intercourse leads to infection. it makes 1 in a 200000 chance. the last factor should be included in this calculation is the accuracy of 4th gen lab tests at 27 days. Hope I will get this answer from you. 

-Questions -

What's the chance that 27 days 4th gen test negative result is false?

and again How accurate is this test at 4 weeks?

Thank you 

H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
19 months ago
Welcome to the forum. Thanks for your quesiton.

Your risk analysis is pretty good and I basically agree -- a few minor tweaks below, but none that make any difference. There is virtually no chance you have HIV.

You don't give enough information about the rash on your back -- "big painful burning red patch" -- to be confident it is herpes zoster (shingles). Without discrete blisters turning into open sores and scabs, probably it is something else. However, if it is painful or bothersome, and if it does have blsiters, sores, etc -- see a doctor for diagnosis and treatment. However, even if is shingles, you still don't have HIV. Although herpes zoster is more common in people with HIV, the vast majority of people with it do not have HIV.

As for your other symptoms (e.g. sore throat, possibly another rash, etc), they are not at all typical of ARS. And the sore throat started too soon. In any case, your negative AgAb test proves you don't have ARS. The symptoms of ARS are caused not by HIV itself, but by the immune response to it -- and it is impossible to have ARS symptoms more than a week or so without having detectable antibody. So although your blood test at 27 days isn't quite conclusive about whtether or not you caught HIV (that time is 6 weeks), it IS 100% proof that any symptoms you have are not due to ARS.

Around 98% of people with new HIV would have positive AgAb test results by 27 days. As just said, you'll need to have another test at 6 weeks for a truly conclusive result, and you should do that for reassurance. You definitely can expect it to remain negative.

As for your exposure, when the penis withdraws from a condom that remains in the vagina, probably protection is complete. 

Now back to your calcuations:  The chance any particular sexually active woman in the US has HIV is more like 1 in a thousand, ten-fold lower than your 1% estimate. The standard estimate for average risk for each episode of unprotected vaginal sex with an infected female partner is 1 in 2,500 (0.0004). As just noted, chance of HIV with negative AgAb test at 4 weeks about 2%. Hence the chance you have HIV calculates as 0.001 x 0.0004 x 0.02 = 0.000000008. If I have correctly counted the zeros, that's 8 in a billion -- or rounding off, 1 chance in 100 million. I hope you will agree that's zero for all practical purposes. (And if you stick with your 1% guess your partner has HIV, we're still at only 1 chance in 10 million.)

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