I have a renewed question from sometime ago. Following a long period of abstinence, for someone who receptively performed oral once recently on a mtf trans sex worker (i.e. male) would you recommend testing, and if so, when and for what? Testing has not occurred in sometime as neither had any sexual contact of this nature. However, there was one recent experience in the last week. No ejaculation occurred. It was effectively a one off after approx 1 Yr or more 'off'. Kissing and frottage also. The individual stated their participation in chemsex ('tina', believe is meth), lives in western Europe, and their health status was not asked, due to being 'out of practice'. Probably worth testing, or do you think this was safe, or safe enough? Thank you - even reading the submitted questions and answers of others is extremely helpful, this is a great service, FWIW. 

Thanks for your kind comments about the forum and for apparently reading other threads starting with questions similar to your own. Having done that, you probably won't be surprised by this reply.

In general, from a medical/risk standpoint, we would not advise HIV testing after any single sexual exposure unless that exposure was particularly high risk, like unprotected vaginal or anal sex with a known infected or especially high risk partner. Oral sex rarely meets that standard, even with a very high risk partner. From these perspectives, I would say that this event was "safe enough" that testing isn't needed. However, reassurance alone often is a valid reason for testing. If you're going to lose sleep worrying and wondering, by all means have an HIV antigen-antibody (AgAb, "4th generation") blood test 6 weeks after the event. (Or you could have an HIV RNA PCR test any time 11 days or more after the event, but these tests are a lot more expensive and with virtually zero risk, even for reassurance I would advise the AgAb test.)

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

Thank you again.

Oral sex is low risk for all STIs. The main possibilities for oral to penile transmission are gonorrhea, nongonococcal urethritis (NGU, often believe to be caused by normal oral bacteria), herpes due to HSV type 1 and syphilis. Absence of symptoms within 1-2 weeks (discharge, painful urination, penile sores or blisters) makes any of these very unlikely. Syphilis can take longer (2-3 weeks) for the initial sore (chancre) to appear. And all these are inherently low risk, i.e. occurring in a very small minority of such exposures. If you would like reassurance, you could have a urine gonorrhea test and a syphilis blood test after 6 weeks. But if I were in your situation, I would feel no need for testing. (There is no test for NGU and the HSV blood tests are not sufficiently accurate to recommend in this situation.)

So feel free to have your reassuring testing at 6 weeks -- but don't lose sleep in the meantime. It is very unlikely you acquired any infection.