hi i had an encounter with a female sex worker, used protection, but the condom slipped off at the end after cilmaxing as i was pulling out. i was on a course of PEP (combivir+kaletra) for 28 days. i was tested at 4 weeks (antibody), 5.5 weeks (p24 duo) and 10 weeks (antibody), all were negative. This is counting from time of possible exposure. I'm now into the 12th week and i'm experiencing some swelling in the parotid glands, a bit of pain in the neck as well as a bit of a rash on my arms and trunk. what are the chances of seroconversion after 10 weeks? i'm planning to get tested again in the next 2 days for week 12 and i've been worrying myself to bits with these recent symptoms. with PEP, is the gold standard now 16 weeks? Thanks for taking the time to answer and the great work on this site!

Hello there Because not enough is known for certain about how PEP may or may not affect the body's normal ability to produce antibodies, should the medication fail and infection occurs, testing guidelines around when to test post PEP vary greatly.

My current recommendation for persons using PEP is that they test at 6 weeks, 3 & 6 months post exposure with a standard antibody test or antibody/ag combination test. I should say that I have not seen a case where a negative test at 3 months post PEP changes with further testing. As such, I think that the further testing at 6 months is simply a precautionary measure.

Hope this helps. Take care LHW