Occupational exposure to HIV and post-exposure prophylaxis in healthcare workers.

Healthcare workers are at risk of occupationally acquired HIV infection primarily due to percutaneous exposure to HIV infected blood. The average risk of HIV transmission after such exposure is approximately 0.3%. There is evidence of higher risk for exposures involving an increased volume of blood (deep injury, injury with a device visibly contaminated with source patient's blood and a procedure which involved a needle placed in the source patient's artery or vein) and exposures to source patients with a high viral load. Triple therapy with two nucleoside analogues (zidovudine, lamivudine) and a protease inhibitor (indinavir) is now widely used for post-exposure prophylaxis following occupational exposure to HIV. Most of the evidence for the efficacy of prophylaxis is based on zidovudine monotherapy. Little is known about the long-term toxicity of these drugs in non-infected individuals. Their use in these circumstances requires careful assessment of possible risks and benefits.