title: Epidemiological and genetic analyses of Hepatitis C virus transmission among young/short- and long-term injecting drug users from Rio de Janeiro, Brazil.
abstract: BACKGROUND
  Injecting drug users (IDU) have a key role in Hepatitis C Virus (HCV) epidemiology. Young/short-term IDUs constitute a target group for preventive/harm reduction interventions.
  
  
  OBJECTIVE
  To investigate HCV transmission among young/short-term (ST) and long-term (LT) IDUs, from the perspective of epidemiology and molecular biology.
  
  
  METHODS
  Cross-sectional study assessing the prevalence of HCV infection/genotypes, as well as risk behaviours/practices among IDUs from Rio de Janeiro. Phylogenetic analyses were performed and the extent of segregation between sequences was quantified by the Association Index.
  
  
  RESULTS
  ST were more likely to engage into needle-sharing (p=.021) and LT to attend Needle Exchange Programs (p=.006). HCV prevalence was 10.1% vs. 23.4% among initiates and LT, respectively (p<.001). Older age vs. imprisonment and longer duration of IDU career were independent predictors for HCV infection among ST and LT, respectively. Among the latter, NEP attendance was inversely associated with viral infection. HCV3a infections were the most prevalent. A moderate extent of phylogenetic segregation between sequences was found, suggestive of transmission between IDU subgroups.
  
  
  CONCLUSIONS
  The lower HCV prevalence among young/short-term IDUs cannot be viewed with complacency, due to their frequent engagement into direct/indirect sharing practices and the ongoing transmission between IDU subsets. To avert new infections, preventive/harm reduction policies must be tailored to empirical findings.
authors.affiliation: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil. mlaoliveira@fiocruz.br
authors.forename: Maria de Lourdes Aguiar
authors.initials: Mde L
authors.lastname: Oliveira
authors.forename: Francisco Inácio
authors.initials: FI
authors.lastname: Bastos
authors.forename: Paulo Roberto
authors.initials: PR
authors.lastname: Telles
authors.forename: Mariana de Andréa
authors.initials: Mde A
authors.lastname: Hacker
authors.forename: Sabrina Alberti Nóbrega de
authors.initials: SA
authors.lastname: Oliveira
authors.forename: Juliana Custódio
authors.initials: JC
authors.lastname: Miguel
authors.forename: Clara Fumiko Tachibana
authors.initials: CF
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D000367:Age Factors; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D055030:Drug Users; D005260:Female; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006526:Hepatitis C / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D015819:Substance Abuse, Intravenous / Q000150:complications*; D055815:Young Adult
chemical_list: D012367:RNA, Viral