Hepatitis C virus infection status and associated factors among a multi-site sample of people who used illicit drugs in the Amazon region

BACKGROUND: Elevated rates of Hepatitis C Virus (HCV) infection have been reported in epidemiological studies with people who used illicit drugs (PWUIDs) in different Brazilian regions. In Brazil’s Amazon region, studies have already identified the common use of illicit drugs among adolescents and the high prevalence of HCV infections among PWUIDs. However, all studies done with PWUIDs were conducted with small samples and within limited geographic coverage. This study determined the prevalence and risk factors for HCV infection in PWUIDs in the Amazon region, northern Brazil, as well as estimating the prevalence and factors associated with the HCV spontaneous clearance (HSC). METHODS: This cross-sectional study accessed 1666 PWUIDs from multiple municipalities of the Amazon region. Socio-demographic, economic, drug use and health-related information were collected through interviews. Blood samples collected were tested for the presence of anti-HCV antibodies and RNA-HCV. HCV genotypes were identified by real-time polymerase chain reaction (PCR). Logistic regressions were run to identify factors independently associated with HCV infection status and HSC. RESULTS: In total, 577 (34.6%) featured HCV antibodies, of which 384 (23.1%) had active HCV infection and 193 (11.6%) indicated HSC. Genotypes 1 (80.2%) and 3 (18.8%) were detected. HCV infection status was associated with the length of illicit drug use history, factors related to parenteral and sexual transmission, and factors of socio-economic marginalization leading to potential risk activities for HCV. HSC was associated with the ethnic (including indigenous) background of participants. CONCLUSIONS: High levels of HCV infection were detected in PWUIDs. Genotype 1 was predominant. Intense use of illicit drugs, unprotected sexual intercourse, high number of sexual partners and social marginalization were associated with all HCV infection. HSC was associated with origin (Amazonian-born) and non-white (e.g., Black or Indigenous) of PWUIDs. These findings emphasize the need for improve HCV prevention and control services and care for PWUIDs in the Brazilian Amazon region. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12879-019-4270-2) contains supplementary material, which is available to authorized users.