LONG-TERM PERSISTENCE OF ANTI-HBS AFTER HEPATITIS-B IMMUNIZATION IN THALASSEMIC PATIENTS

An epidemiological study was carried out on 114 beta-thalassaemics in order to select those subjects susceptible to hepatitis B virus (HBV) infection for hepatitis B vaccination. The results confirmed the high risk of HBV infection in these patients: 9.6% were HBsAg positive, 29.8% were anti-HBs positive/anti-HBc positive, and 9% were anti-HBc positive. In 60 HBV-negative patients, 20 mug doses of hepatitis B vaccine were administered on a schedule of 0, 1 and 6 months. Sera were collected for six years to determine the seroconversion rate and the anti-HBs titre. Seroconversion reached a maximum rate of 93% 12 months after the first vaccination dose and was 80% at the final control (72 months). Highly protective anti-HBs titres were observed until the last control in a high percentage of subjects. The HBVax hepatitis B vaccine has been shown to be safe, immunogenic and effective in beta- thalassaemics.