Twenty-year follow-up of an outbreak of hepatitis C in a small rural town of Argentina: The O'Brien Project

Abstract

Introduction and objectives: In 1999, a population-based survey showed a 5.6 % (102/1832) prevalence of HCV infection in O'Brien, a small rural town of Argentina. The aim of this study was to assess the impact of screening, clinical evaluation and antiviral therapy on elimination of HCV after 20 years of follow-up.

Patients and methods: HCV+ subjects (n=102) underwent clinical, biochemical and histological evaluation to assess the presence and severity of liver disease. Antiviral therapy included pegylated interferon + ribavirin in 2005 and direct antiviral agents from 2017.

Results: All viremic subjects (n=84) had genotype 1b with 90%-97.5% sequence homology scores, suggesting the existence of a common source of infection (use of unsafe injections administered by the same health professional). Liver biopsy (n=55) showed chronic hepatitis in all patients. The prevalence of cirrhosis was 28% overall (29/102) and 34.5% among viremic patients. Sustained virological response (SVR) was obtained in 20/34 (59%) patients treated with interferon. From 2005 to 2017, when oral antivirals became available 37/50 untreated patients died. Median age of this group in 2005 was 67 years. Six interferon non-responders and five naive subjects received direct antiviral agents and all developed SVR. Only 1/31 patient (3.2%) with SVR died and none developed decompensated cirrhosis or HCC. In 2019, a new population-based study showed that the prevalence of HCV in O'Brien decreased 20-fold, from 5.6% to 0.28% (3/1070).

Conclusions: Despite the high mortality rate precluding timely access to direct antiviral agents, the O'Brien Project is a good example of HCV micro-elimination studies.

Keywords: Antiviral therapy; Epidemiology; Hepatitis C virus; Micro-elimination; Natural history.