I am now riddled with anxeity from my stupid behaviour. Everything I have read says its very unlikely in the uk that a white women who does not inject drugs would have HIV. I have also read that vagina to penis transmission from a partner with HIV is only likely to happen every 1 in 1000 incedents. Is this correct? I was going to go to the hospital tomorrow and get PEP. Should I do this or not? Should i test? I am usually very cafeful to stay protected as I have bad anxiety at the best of times

Thank you in advance for your answer

You've pretty well scoped out the HIV risk here:  I have the same understandings you have about the frequency of HIV in partners like yours. This might have been on the high risk side; for obvious reasons, HIV rates are higher in persons likely to consent to sex in situations like yours. That your partner was willing to proceed without a condom can be viewed as either high risk (for obvious reasons) or low risk (that she genuinely believes she has no transmissible STI, about which most people are pretty accurate). But even if she did have HIV, the transmission risk to you was even lower than one in 1,000:  the US CDC estimate for unprotected vaginal sex is 1 in 2,500 for the male partner, if the woman has HIV. Your chance probably would be lower still, because the exposure was brief.

We do not give direct advice about post-exposure prophylaxis (PEP) to prevent HIV. PEP decisions should be made by local providers who understand the local epidemiology and risks, and can directly counsel the patient about the pros and cons. (For example, a GUM clinic or local urgent care clinic might have more detailed information about the likelihood a partner like yours had HIV.) That said, I would be strongly inclined against PEP. Considering the issues mentioned above, I would put your chance of having acquired HIV and needing PEP at under one chance in a million. And there's a downside to PEP that lots of people (including health care providers) forget:  without PEP, you can have nearly conclusive HIV PCR testing in 10-12 days; with it, the earliest reliable test time is 6 weeks away, i.e. 10-12 days after your last dose of drug. And since common advice is to follow PCR testing with an AgAb (4th generation) blood test at 6 weeks, final testing might be almost 3 months away. Would you be prepared to be wondering and worrying that long?

Your risk for other STIs is a lot higher than for HIV. Regardless of what you do about HIV testing or PEP, I would advise a urine test for gonorrhea/chlamydia in a few days (any time 4-5 days or more after exposure) and a syphilis blood test in about 6 weeks.

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

HHH, MD

Could I get clarity on two points please.  you mentioned unprotected vaginal sex is 1 in 2,500 for the male partner which I understand as for every 2500 instances of unprotected sex it is likey that only one instances would infect, so my risk in this one instance was 0.04% so well under 1 percent out of a hundred so to low to worry unduly about? Have I understood this correctly.

You later mention the following- I would put your chance of having acquired HIV and needing PEP at under one chance in a million. Was this estimation due to the briefness of the exposure?

Thank you in advance

Glad I understood the first one correctly and thank you for the clarification on the second one.

Have a great weekend and thank you for the speedy reply.

Thank you  

Online information overemphasizes symptoms of new HIV infections. Symptoms almost always are totally useless:  the typical symptoms of ARS usually have other causes (even in people at high risk for HIV); and more than half of newly infected persons have no symptoms at all. Always ignore symptoms entirely, whether present or absent  --  and rely only on exposure risk and blood test results.

That completes the two follow-up comments and replies included with each question and so ends this thread. I hope the discussion has been helpful. Best wishes -- and don't worry about HIV!