- In Israel, as in certain European countries, national health guidelines exist for preventive treatment after possible post-coital exposure to the HIV virus. Scientifically, this treatment is still regarded as experimental, though over the past years there is a mounting level of evidence of its efficacy. The administration of prophylaxis for HIV after unprotected coitus may be justified by the similar risk of HIV transmission for certain sexual and occupational exposures. Other considerations include: biological plausibility, the effectiveness of post-exposure prophylaxis in animal studies and occupational exposures in humans, efficacy in the prevention of vertical HIV transmission, and cost effectiveness studies. The preventive post-exposure treatment bears many side effects and possible complications, and therefore, each case should be cautiously analyzed before starting such treatment. This article reviews the scientific evidence on this topic, the considerations taken by the physician in initiating post coital HIV exposure treatment, and the guidelines available in Israel and throughout the world.