Risk for occupational transmission of human immunodeficiency virus type 1 (HIV-1) associated with clinical exposures. A prospective evaluation.

OBJECTIVES

To summarize the results of a 6-year, ongoing, prospective study of the risk for human immunodeficiency virus type 1 (HIV-1) transmission among health care workers, and to estimate the magnitude of the risk for HIV-1 infection associated with different types of occupational exposures.

DESIGN

Prospective cohort study; the median follow-up for employees sustaining parenteral exposures was 30.2 months (range, 6 to 69 months).

SUBJECTS: Health care workers at the Clinical Center, National Institutes of Health, including those reporting parenteral and nonparenteral occupational exposures to HIV-1.

MEASUREMENTS AND MAIN

RESULTS

One thousand three hundred and forty-four clinical health care workers reported 179 percutaneous and 346 mucous membrane exposures to fluids from HIV-1-infected patients during a 6-year period. Responding to a supplementary questionnaire, 559 of these workers reported 2712 cutaneous exposures to blood from HIV-1-infected patients and more than 10,000 cutaneous exposures to blood from all patients during a 12-month period. Occupational transmission of HIV-1 occurred in a single worker after a parenteral exposure to blood from an HIV-1-infected patient. No infections occurred after either mucous membrane or cutaneous exposures to blood from HIV-1-infected patients. Use of newer diagnostic technologies (for example, antigen detection, gene amplification) has not resulted in the identification of occupationally transmitted seronegative infections.

CONCLUSIONS

Combining our results with those of other prospective studies, the risk for HIV-1 transmission associated with a percutaneous exposure to blood from an HIV-1-infected patient is approximately 0.3% per exposure (95% CI, 0.13% to 0.70%); the risks associated with occupational mucous membrane and cutaneous exposures are likely to be substantially smaller. These data support the use of barrier precautions and suggest a need for strategies that change health care providers' attitudes and behaviors.