PREVALENCE OF HEPATITIS-A VIRUS-INFECTION AMONG SEWAGE WORKERS IN SINGAPORE

To determine whether or not occupational exposure to sewage is associa ted with a higher seroprevalence of hepatitis A virus (HAV) infection, 600 sewage workers in Singapore were tested for total (IgG and IgM) a ntibody to HAV by enzyme immunoassay. Using logistic regression with s tepwise procedure, the adjusted seroprevalence of sewage workers was 2 .2 times higher than that of another non-occupationally exposed popula tion group. Seroprevalence was significantly correlated with age and e ducational levels, the association being independent of the occupation al association. The epidemiological data in the study show that sewage workers have an increased occupational risk of acquiring HAV infectio n and should be protected by active immunization.