Viral hepatitis : a four‐year hospital and general‐practice study in Sydney

Clinical and serological study of household contacts of index patients suffering from acute viral hepatitis showed the high infectivity of hepatitis A viral (HAV) for susceptible contacts. The anti-HAV specific IgM developed in sera of 67% of susceptible children and 31% of susceptible adult contacts. Of 81 susceptible contacts whose sera became anti-HAV positive, 28.4% developed clinically overt hepatitis. Administration of human immunoglobulin reduced the rate of clinical expression of hepatitis A among susceptible contacts; it also appeared to reduce the actual infection rate. The infection rate among susceptible adult contacts of adult index cases suffering from hepatitis B was 24%. Of 25 susceptible contacts whose sera became HBV-marker positive, 24% developed clinical illness. Transmission occurred probably both by parenteral and non-parenteral means. It is currently not possible to determine susceptibility or seroconversion to hepatitis non-A non-B agents.