Angst Over Anal

Dear Doctors,

I am a 51 year old gay man. I  have practiced safe sex for years, and I've been rewarded with an HIV negative status annually.  I always ask my prospective sex partner their HIV status prior to any sexual contact, always. I made a promise to myself a decade ago that I would not have unprotected anal sex ever again. I stuck to that until about three and a half weeks ago. "Heat of the moment"? I had a very brief non-traumatic plenty of lube anal receptive sexual encounter that was of very short duration...(two minutes at most), until I came back to my senses, asked to stop and we did. No ejaculation. So, I suppose I managed to do a couple things right...I asked first about his HIV status prior to sex, and he was adamant about his negative status. Still is. Ten days after my brief but angst producing exposure, I had a rapid Oraquick HIV test which I was going to have done anyway, and at the same time they also drew blood for an RNA (PCR..I believe) test. I've had maybe four sex partners in the last three years, using safe sex practices always...except for this one encounter. The rapid test was negative as I assumed it would be. The RNA test came back negative as well.

1) CDC says the window period for RNA tests, 9-11 days. Mine was 10 days. Will this test have any significance in my scenario, ten days post exposure?

2) You have probably repeated this hundreds of times for other similar cases, but would a rapid test at four and a half weeks be advisable....Did I read in some other post that a test at four weeks is reliable?

Thank you for your time. I appreciate it.

W.

[H. Hunter Handsfield, M.D.]

Welcome to the HIV forum.

Congratulations for a common sense, level headed approach to your sexual behavior.  You're doing all the right things.  If you told me you had this sort of lapse all the time, I would worry.  But remember that even if your partner lied about his HIV status -- which is uncommon -- the risk of transmission during any single episode of unprotected receptive anal sex (with an HIV infected partner) averages around 1 in 200.  Now I would not recommend anybody play Russian roulette with a mythical 200-chamber pistol, but most people would survive.  Given the relative brevity of the exposure, apparently without intr-rectal ejaculation, your risk was still lower.  And it seems very doubtful your partner has HIV.

I'm pretty sure you know all this -- but to cement the message, let's do a back of the envelope calculation.  Chance your partner had HIV, despite his strong reassurance:  let's say 1%.  Chance of transmission, in absence of ejaculation:  let's say 1 in 500 (0.2%).  Chance of a false negative HIV RNA test at 10 days?  I'm not sure, but let's say it's as high as 10%.  With these figures, the chance you were infected comes to 0.01 x 0.002 x 0.1 = 0.000002.  That's 2 in a million, or 1 in 500,000.

When to test again depends on how much reassurance you would like beyond 1 chance in half a million.  At 4 weeks, the standard HIV antibody tests (either rapid or lab-based) detect at least 90% of infections.  Would you sleep better knowing your risk were 1 in 5 million instead of 1 in 500,000?  If so, get tested at 4 weeks.  If you would like to make it 1 in 500 million, have a test at 6-8 weeks, by which time ~99% of infections are detected.

Bottom line:  The odds are overwhelmingly in your favor.  It seems to me the easiest thing would be for you to have a routine (or rapid) HIV antibody test around 8 weeks after the exposure. In the meantime, you can rest easy and definitely expect a negative result.

Regards-- HHH, MD