IMMUNE-RESPONSE TO HEPATITIS-B VACCINE IN PARENTERAL DRUG-ABUSERS

Responsiveness was assessed to a programme of vaccination of hepatitis B vaccine in a cohort of 197 intravenous drug addicts (mean age, 23.7 years) and their antibody response was compared with that of 2 71 healthy controls (mean age, 24.2 years). All participants were seronegative for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs). The vaccination schedule consisted of three intramuscular injections (deltoid area) at months 0, 1 and 2. Although 70% of parenteral drug abusers received the three doses of vaccination, only 43.6% were evaluable for immune response. Fifty-eight per cent of heroin addicts and 80% of controls had evidence of anti-HBs seroconversion at 1 month after vaccination (chi-2 = 15.52, p < 0.001). Geometric mean antibody titres were also significantly higher in controls (69.1 IU l-1; confidence interval 95%, 56.83 and 84.04) than in parenteral drug abusers (18.2 IU l-1; confidence interval 95%, 12.85 and 25.73) (F = 20.951, p < 0.0001). The anti-HBs response was not influenced by coexistent anti-HBc, HCV antibody or HIV antibody seropositivity.