The epidemiology of hepatitis C in Switzerland: trends in notifications, 1988-2015

With an estimated antibody prevalence of 0.7% in the low-risk population, hepatitis C virus (HCV) endemicity in Switzerland is low. We reviewed data from mandatory hepatitis C surveillance for 1988-2015 in order to describe the evolution of acute HCV infections and newly reported non-acute cases, and their epidemiological features. Crude and stratified annual incidence and notification rates and rate ratios were calculated using Poisson regression. Acute HCV incidence peaked in 2002 at 1.8 cases per 100,000 population, then declined sharply, levelling at around 0.7/100,000 from 2006. Notification rates for non-acute HCV cases peaked in 1999 (38.6/100,000), decreasing to 16.8/100,000 in 2015. Men constituted 65.5% of acute cases and 60.4% of non-acute cases. During the periods 1992-1995 and 2012-2015, the median age of acute cases increased from 28 to 37 and of non-acute cases from 32 to 48 years. The exposure leading to most acute (90.4%) and non-acute (71.9%) cases was presumably in Switzerland. Despite a sharp decrease since 2000, injecting drugs was the main reported exposure for both acute (63.8%) and non-acute (66.6%) cases, with a known exposure, followed by sexual contact with an infected person (18.9% and 10.3% respectively). Among all acute cases, the number of men who have sex with men increased sharply after the mid-2000s, totalling 41 during 2012-2015 (25.7%). Although the HCV epidemic peaked in 2000 - probably as a result of measures to control iatrogenic and percutaneous transmission - Switzerland must maintain prevention and surveillance.