Post-exposure prophylaxis revisited: new CDC guidelines. Centers for Disease Control and Prevention.

The Centers for Disease Control and Prevention (CDC) convened a meeting in 1997 to revisit guidelines for post-exposure prophylaxis (PEP) for occupationally acquired HIV infection. Recent data show that the health care worker's infection risk is increased with deeper injury, bloodier needles, and source patients with more advanced disease suggesting higher viral load. A CDC study shows that AZT use of any kind was associated with an 81 percent reduction in the risk of seroconversion compared with controls not given AZT. AZT is the only drug for which proof exists of clinical benefits in the prophylaxis setting. However, attempts to assess AZT's efficacy in a randomized, prospective, placebo-controlled trial have failed, making the assessment of PEP's efficacy unlikely in the future. PEP initiation, according to the CDC, is guided by two principles: relative risks of exposure and the risks of the injury balanced with risks of the drug therapy. Future treatment guidelines are likely to pay more attention to the source patient, disease stage, and/or viral load as determinants of risk. Other nucleotides and protease inhibitors could arguably be included in PEP regimens, particularly for treatment of high-risk cases. Studies show no fetal harm from AZT; there is little information on fetal toxicity of other antiretrovirals. New guidelines are due to be published in the MMWR in early 1998.