However, PEP always is comprised of combination therapy; neither
lamivudine nor any other
drug, used alone, has been studied. Doing so risks getting infected with a drug-resistant strain of HIV, so it could actually make things work.
2) It just doesn't. No medical condition has any such effect on HIV testing. It has to do with the complexities of the immune system. I'm not enough of an expert in that arena to give you a detailed biological explanation.