Approaching measles elimination in Switzerland: changing epidemiology 2007-2018.

Switzerland is aiming to eliminate measles, in line with the objectives of the World Health Organization (WHO). Physicians, laboratories and public health authorities have made great efforts to reach this goal. A continually increasing measles vaccination coverage and other preventive measures have made an impact: no major measles outbreak has been recorded since 2011. In order to evaluate progress towards elimination, measles epidemiology of a previous epidemic period (2007–2011) was compared with the current post-epidemic period (2012–July 2018) by analysis of data from the mandatory notification system. A decrease of 94% in the average annual incidence rate occurred between the two periods (from 133 to 9 cases per million inhabitants). This was accompanied by significant changes in the epidemiology that are expected and characteristic of countries with limited circulation of the measles virus. After analysing the performance of the Swiss surveillance system and the data provided, the WHO concluded that endemic measles transmission was interrupted in Switzerland in 2016 and 2017.

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.

Reduction of acute hepatitis B through vaccina-tion of adolescents with no decrease in chronic hepatitis B due to immigration in a low ende-micity country.

With a hepatitis B prevalence of 0.3%, Switzerland is a country with low endemicity. Unlike most other countries, Switzerland's recommendation for vaccination against hepatitis B has since 1998 focused on adolescents aged 11 to 15 years rather than on infants, in addition to risk groups since 1982. This paper describes the evolution of the incidence of acute hepatitis B virus (HBV) infection and newly reported chronic cases in Switzerland, as well as their epidemiological features, in order to discuss the implications for the control of hepatitis B through vaccination. Data from mandatory notifications by physicians and laboratories between 1988 and 2015 were analysed for acute and chronic HBV infection. Crude and stratified incidence and notification rates (IR, NR), and incidence and notification rate ratios (NRR, IRR) by year were calculated by means of a Poisson regression. Acute HBV incidence peaked in 1992 at 7.5 cases per 100 000 population and subsequently declined by 11% annually (IRR 0.89, p <0.001) to the lowest rate of 0.4/100 000 in 2015. The decrease in incidence accelerated after the introduction of vaccination for adolescents (IRR 0.93, p <0.001 vs 0.91, p <0.001), and was more pronounced in the targeted age groups (IRR 0.90, p <0.001 vs 0.84, p <0.001 for age 15-19 years and IRR 0.92, p <0.001 vs 0.83, p <0.001 for age 20-24). The use of injectable drugs as an assumed source of exposure decreased from 58.1% to 1.9% of all exposures between 1988-1991 and 2012-2015, while sexual contact with an infected person increased from 10.3% to 67.9%. The NR of chronic cases increased until 1995, then stabilised at around 15/100 000. A growing majority of the chronic cases originated abroad (58.4% in 1988-1991 and 82.2% in 2012-2015), and the NR was significantly higher for foreigners than for Swiss nationals (NRR 7.92, p <0.001), especially when compared with the IRR of 1.55 (p <0.001) for acute cases. The introduction of universal vaccination of adolescents combined with vaccination of risk groups and other nonvaccine-related measures has brought acute HBV infection under control in Switzerland. However, the rate of new notifications of chronic HBV infection has remained stable, largely as a result of the immigration of people chronically infected prior to arrival. The burden of disease is thus likely to increase, requiring the strengthening of secondary prevention of chronic HBV infection, in addition to renewed efforts to vaccinate people and their families originating from countries with high endemicity, and persons who frequently change sexual partners.