Bloodborne viral hepatitis infections among drug users: the role of vaccination.

Drug use is a prevalent world-wide phenomenon and hepatitis virus infections are traditionally a major health problem among drug users (DUs). HBV and HCV, and to a lesser extent HAV, are easily transmitted through exposure to infected blood and body fluids. Viral hepatitis is not inevitable for DUs. Licensed vaccines are available for hepatitis A and hepatitis B. The purpose of this overview is to show some epidemiological data about HBV and the other blood-borne viral hepatitis among DUs and to summarize and discuss use of hepatitis vaccinations in this population. Successful vaccination campaigns among DUs are feasible and well described. We try to focus on the most significant results achieved in successful vaccination programs as reported in scientific literature. Vaccination campaigns among DUs represent a highly effective form of health education and they are cost-saving.

Immunogenicity, reactogenicity and adherence to a combined hepatitis A and B vaccine in illicit drug users.

AIMS: The use of illegal drugs is associated with an increase in infective risk for the hepatitis viruses, against which the vaccination of drug users (DUs) is recommended unanimously. The aim of the study was to determine tolerability, adherence and immune response of a combined vaccine providing dual protection against hepatitis A virus (HAV) and hepatitis B virus (HBV). METHODS: The vaccine was administered to 38 DU, attending three public health centres for drug users in northern Italy, with a three-dose schedule (at 0, 1 and 6 months). The vaccine was well tolerated: only one adverse reaction (fever) was recorded after the 110 doses administered (0.9%). The vaccine schedule was completed successfully in 35 cases (92.1%). At month 8, in 34 subjects (89.5%) antibody response was evaluated: all showed seroprotection for HAV and in 33 subjects (97.1%) for HBV. CONCLUSIONS: The vaccine, studied for the first time in DUs, proved to be safe, well accepted and immunogenic; anti-HAV response was 1272 mIU/ml and 1726 mIU/ml for anti-HBV, titres lower than reported in literature for the general population. This study suggests that DUs who are HAV/HBV-negative could be vaccinated with combined vaccine.

Immunogenicity, reactogenicity and adherence with hepatitis A vaccination among drug users.

Hepatitis A virus (HAV) vaccination is recommended in drug users (DUs) because this population has a very high prevalence of hepatitis C virus, and additional infection with HAV can lead to increased morbidity and mortality. The efficacy of hepatitis A vaccine (1440 ELISA units), in terms of immunogenicity, reactogenicity and compliance among 44 heroin DUs using a 0-6 month schedule was investigated. Three subjects (6.8%) experienced adverse reactions. After the first dose of hepatitis A vaccine, 37% of subjects seroconverted. Two months after the 6-month booster vaccination, all vaccinated patients became seropositive. The mean serum antibody concentration was 40 mIU/ml after 6 months and 558 mIU/ml after 8 months. Although all DUs proved seropositive after the booster vaccination, the seroconversion rate, at the 2 and 6 months time points was much lower than in healthy subjects. The lower geometric mean titre could affect the kinetics of decrease of antibody titres and the protection conferred by vaccination may be less durable in these patients. These findings indicate that the 0-12 months schedule could be reduced to a shorter 0-6 months schedule in order to shorten the unprotected period. Further studies among drug users are needed to explore the efficacy and immunogenicity of higher doses or alternative schedules of HAV vaccine.