Hepatitis C virus infection in healthcare workers: risk of exposure and infection.

OBJECTIVES: To determine the incidence of hepatitis C virus (HCV) infection among healthcare workers (HCWs) at a university hospital, the proportion of HCWs having non-A, non-B hepatitis (NANBH) who were anti-HCV positive, and the rate of HCV transmission following a HCV-positive needlestick injury. DESIGN: Longitudinal analysis of a dynamic (cohort) population. MEASUREMENTS: From 1980 through 1989, HCWs who had clinical NANBH were identified, and from 1987 through 1989, HCWs who reported a blood or body fluid exposure and the patients who were the source of the exposure were screened for antibodies to HCV. SETTING: A 732-bed, university hospital and outpatient clinics. RESULTS: Over the 10-year period, six cases of occupationally acquired NANBH were observed, for an incidence of 21 cases per 100,000 HCWs per year (standardized incidence ratio, 2.96; 95% confidence interval [CI95], 1.83 to 4.36). Four of the six cases were confirmed to be HCV infection. From 1987 through 1989, 176 (12.7%) of 1,387 patients who were the source of an exposure were anti-HCV positive. Exposures that occurred in the emergency department were more likely to be anti-HCV positive than were exposures from all other locations (relative risk [RR] = 1.7; P = 0.009). Of HCWs who had an HCV-positive needlestick injury and whose serum had been tested for anti-HCV at least 5 months after the exposure, 3 (6.0%) of 50 seroconverted. From 1987 through 1989, the incidence of HCV infection among HCWs was 54 cases per 100,000 HCWs per year. CONCLUSION: The incidence of clinical NANBH among HCWs in this study is approximately three times higher than that of non-HCWs. HCWs are at significant risk for exposure to and acquisition of HCV.

Decline of clinical hepatitis B in workers at a general hospital: relation to increasing vaccine-induced immunity.

Hepatitis B is a well-recognized occupational hazard of health-care workers that can be prevented with vaccination. However, because data on the current epidemiology of hepatitis B virus (HBV) in this population are limited, no consensus exists regarding the requirement for immunization. In 1980-1989, 4,908 exposures of health-care workers to patients' blood and/or other body fluids were reported and evaluated at a general hospital. During this period, 4.8% of patients to whom health-care workers were exposed were positive for hepatitis B surface antigen (HBsAg). In exposed workers, the rate of protective immunity to HBV (measured by antibody to HBsAg) increased from 14% in 1980 to 55% in 1989. Hepatitis B vaccine became available at this hospital in 1983. The increase in antibody to HBsAg was not associated with an increase in antibody to HBV core antigen; this finding suggests that the increase in immunity was primarily vaccine induced. The incidence of reported clinical hepatitis B in health-care workers decreased from 82/100,000 in 1980-1984 to zero in 1985-1989 (odds ratio = 20.06; P = .0012). Thus, in this study, a program of hepatitis B immunization for health-care workers was associated with a significant decline in clinical HBV infection despite continued exposure to patients positive for HBsAg.