Results of a hepatitis C microelimination project in an addiction treatment center.

Background: Patients on opioid substitution therapy constitute a collective with a high burden of hepatitis C and candidate to interventions aimed to microelimination.

Aims: To analyze the baseline prevalence of both previous contact and/or active infection patients, measure the response to current treatment provided through a simplified circuit and estimate the impact of this intervention on reduction of proportion of viremic population.

Methods: People affiliated in an addiction treatment center was subjected to an in situ diagnostic sequence using a saliva serological screening and viremia quantification with dry blood spot test. Viremic patients were linked to care and treatment was administered in the first single appointment with pan-genotypic direct-acting antivirals. The McNemar test was used to compare proportions of active infection before and after intervention.

Results: With a participation of 99.2%, seroprevalence for hepatitis C was 44.6% (115/258) while active infection was present in a 20.9% of seropositive people (24/115). The response rate to treatment was 54.2% by intention-to-treat and 61.9% by per-protocol analysis. Successfully treating of 13 patients allowed to estimate a global reduction of active infection rate from 9.3% to 4.3% (p=0.0002), for a theorical scenario with no reinfections. By adjusting for the known reinfection rates, the prevalence of active infection also decreased a 4.2% for people with assumed no recent drug use (p=0.0074), but no changes were found for estimates in patients with supposed recent drug use (p=0.2632).

Conclussions: Focused efforts targeted to this high-risk group, including both screening and treatment initiatives, can potentially reduce the prevalence of active hepatitis C infections.