Last night I had an exposure with a CSW. We started with kissing and then I put my condom on and went for vaginal sex. As I was too drunk my penis was not fully erect so I was not able to get it in so she  started giving me a blowjob and then she sat on top of me but as I was totally drunk I was not able to get a full erection and did not penetrate her. 

After that I told her to come down and we started kissing again and rubbing our body against each other, at that time I noticed that my condom had slipped off. As I was drunk I do not know when the condom came off , but I am pretty sure that I did not penetrate her as without a condom there is always a sensation, at best I might had tried to penetrate her but was not able to....  my question are

1. Am I at risk of any infection? 

2. Do I need to test for hiv and other stds?

3. I saw that you have changed the testing guidelines for 4th Gen test from 28 days to 42days..any reason for that? 

Kindly help as I am totally messed up? 

Thanks

As I think we discussed in your earlier threads, condom protected sex is low risk; kissing and hand-genital contact little or no risk, even if genital fluids are used for lubrication; and genital apposition without penetration is low risk as well, although not zero risk. The main uncertainty here, it seems to me, is that there might have been brief penile-vaginal penetration, but so brief that I think it's not a serious worry. Also remember that even among the highest risk people, including female commercial sex workers, at any one time most are not infected with HIV or other STDs; and that most STDs are not transmitted with high efficiency, i.e. most exposures don't result in transmission.

To your specific questions:

1) There probably was low risk for those STDs transmitted skin-to-skin (herpes, HPV, syphilis) and extremely low risk for those transmitted by genital fluids (gonorrhea, chlamydia, HIV, and a few less common infections).

2) "Need" to test is largely up to you. Most likely you acquired no STD, but that can't be guaranteed. Most likely you will be pretty anxious unless and until you are tested and have negative results, so I would recommend a urine test for gonorrhea and chlamydia, which will be valid after 4-5 days; and blood tests for HIV and syphilis after 6 weeks. Another option is to contact your commercial partner and offer to pay for testing for her. If negative for gonorrhea, chlamydia, HIV and syphilis, you will know you were not exposed and would not necessarily need testing yourself.

3) A little over a year ago a published summary of HIV test performance showed that in rare cases the antigen-antibody ("combo", 4th generation) HIV blood tests take up to 6 weeks to become positive. At that time we modified our advice on this forum from 4 to 6 weeks. However, at least 98% of newly infected people have positive results by 4 weeks, so a negative test at that time remains highly reliable -- but not quite perfect.

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

HHH, MD