Prevalence and Incidence of Viral Hepatitis in Health Workers in the Prehepatitis B Vaccination Era

Abstract

To assess the impact of hepatitis B virus on health workers, the authors studied baseline prevalences of hepatitis B serologic markers and undertook prospective surveillance to assess hepatitis B attack rates in 837 health workers and 994 blood-donor controls between 1977 and 1982, before the introduction of hepatitis B vaccine. The baseline prevalence of all hepatitis B markers was 14% in health workers and 6% in controls (p < 0.001); exposure to hepatitis B virus was related to the intensity of blood exposure and its duration. In contrast, the frequency of exposure to hepatitis A virus a nonblood-borne agent, was lower in health workers (11%) than in controls (16%) (p < 0.01) and increased as a function of age. Multivariate logistic regression analysis identified occupational categories with frequent blood contact, rather than duration of exposure, as being the dominant variable for exposure to hepatitis B virus; for hepatitis A virus exposure, age was the most significant variable. Among health workers susceptible to hepatitis B, the incidence of new definite hepatitis B infections was 1.0% per year in 362 health workers (804 person-years of follow-up observation) with frequent blood contact versus 0% per year in 258 health workers (534 person-years of observation) with limited blood contact (p = 0.017). For definite plus probable cases combined, the incidence of new hepatitis B infections was 1.5% per year versus 0.2% per year for the groups with frequent and limited blood exposures, respectively (p = 0.0013). There were no new cases of hepatitis A or B or seroconversions in controls and only one case of hepatitis A acquired outside the hospital by a health worker. These data confirm the high prevalence of hepatitis B exposure and document in a prospective study the high incidence over time of new hepatitis B virus infections in health workers unprotected by vaccination. Such findings reiterate the need for aggressive vaccination programs in health workers xposed to blood. Am J Epidemiol 1992; 136: 603–10