title: Immunogenicity, reactogenicity and adherence with hepatitis A vaccination among drug users.
abstract: 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.
authors.affiliation: Medical Service for Addictive Disorders, Department of Internal Medicine, University of Verona, Verona 37134, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Quaglio
authors.forename: Benedetta
authors.initials: B
authors.lastname: Pajusco
authors.forename: Paolo
authors.initials: P
authors.lastname: Civitelli
authors.forename: Sabrina
authors.initials: S
authors.lastname: Migliozzi
authors.forename: Don C
authors.initials: DC
authors.lastname: Des Jarlais
authors.forename: Luisa
authors.initials: L
authors.lastname: Romanò
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lechi
authors.forename: Paolo
authors.initials: P
authors.lastname: Mezzelani
authors.forename: Fabio
authors.initials: F
authors.lastname: Lugoboni
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D005260:Female; D006506:Hepatitis A / Q000097:blood* / Q000276:immunology / Q000517:prevention & control; D022362:Hepatitis A Vaccines / Q000097:blood* / Q000276:immunology / Q000627:therapeutic use; D006801:Humans; D007104:Immune Adherence Reaction / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D010349:Patient Compliance / Q000706:statistics & numerical data; D019966:Substance-Related Disorders / Q000097:blood* / Q000276:immunology
chemical_list: D022362:Hepatitis A Vaccines