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This document is a reply to a critique of a paper on the prevalence of hepatitis C virus (HCV) infections in Switzerland. The authors of the reply address the criticisms made by the critique and defend their estimates of HCV prevalence in Switzerland. They argue that the critique's assumptions and methodology are flawed and provide evidence to support their own estimates. They also mention positive feedback they received from other scientists in the field. The authors conclude that Switzerland has reached the World Health Organization's elimination targets for HCV and that prevalence estimates should be revised. [Extracted from the article]

In this multi‐method study, we investigated the prevalence of chronic infections with the hepatitis C virus (HCV) in Switzerland in 2020, and assessed Switzerland's progress in eliminating HCV as a public health problem by 2030 with regard to the World Health Organization (WHO) criteria targeting infections acquired during the preceding year ('new transmissions') and HCV‐associated mortality. Based on a systematic literature review, the reappraisal of a 2015 prevalence analysis assuming 0.5% prevalence among the Swiss population and data from many additional sources, we estimated the prevalence among subpopulations at increased risk and the general population. For new transmissions, we evaluated mandatory HCV notification data and estimated unreported new transmissions based on subpopulation characteristics. For the mortality estimate, we re‐evaluated a previous mortality estimate 1995–2014 based on new data on comorbidities and age. We found a prevalence of ≤0.1% among the Swiss population. Discrepancies to the 2015 estimate were explained by previous (i) underestimation of sustained virologic response numbers, (ii) overestimation of HCV prevalence among PWID following bias towards subgroups at highest risk, (iii) overestimation of HCV prevalence among the general population from inclusion of high‐risk persons and (iv) underestimation of spontaneous clearance and mortality. Our results suggest that the WHO elimination targets have been met 10 years earlier than previously foreseen. These advancements were made possible by Switzerland's outstanding role in harm‐reduction programmes, the longstanding micro‐elimination efforts concerning HIV‐infected MSM and nosocomial transmissions, little immigration from high‐prevalence countries except Italian‐born persons born before 1953, and wealth of data and funding. [ABSTRACT FROM AUTHOR]

Background: Asylum seekers in Switzerland have to register in federal asylum centres (FACs) before formal permission to enter the country. Some of them may have active tuberculosis (TB), exposing fellow refugees and employees. Objectives: The aim of this study was to assess the risk of TB infection among employees of Swiss FACs. Methods: Between 2010 and 2018, a free interferon-gamma release assay (IGRA) was offered to all employees of 8 FACs, at employment and at yearly intervals. We defined latent TB infection as IGRA conversion from negative to positive. IGRA-positive employees were referred to a medical centre for further clinical follow-up. Results: 1,427 tests were performed among 737 employees (54.6% male). 403 (55%) persons were tested only once; 330 (44.5%) were tested several times; for 4 (0.5%) persons, the number of IGRA tests is unknown. Twenty employees (2.7%) had a positive IGRA at baseline, 2 (0.6%) converted from negative to positive during follow-up, resulting in an incidence of 22/10,000 person-years. We observed no case of active TB among employees. Conclusions: The prevalence of latent TB among employees to Swiss FACs and the risk of acquiring TB infection through work-related exposure are low. Yearly IGRA controls in the absence of documented TB exposure seem unnecessary. [ABSTRACT FROM AUTHOR]

Sexualised drug use (SDU), the use of drugs in a sexual context, has emerged as a marker of high-risk sexual activity and poor sexual health among gay, bisexual and other men who have sex with men, however, there are no robust estimates of the prevalence of SDU. The primary sources of surveillance data on SDU should include both sexual health and drug treatment services. The challenges to achieving comprehensive, timely and valid SDU surveillance include establishing case definitions, selecting appropriate surveillance settings, and normalising the monitoring of SDU at clinical services. In this commentary we propose a means to address these challenges and discuss other sources of SDU data from ad hoc population surveys and sentinel systems. We also present case studies of SDU surveillance development in England and Switzerland. The patterns of SDU will be affected by a rapidly changing drug market and, as a result, surveillance systems must continuously adapt to ensure that they are fit for purpose and can provide data to guide policy. [ABSTRACT FROM AUTHOR]

Objectives: In Switzerland, universal health insurance does not cover any routine testing for sexually transmitted infections (STIs), not even in individuals at high risk, and extra-genital swabbing is not standard of care. We compared STI prevalence in a multicentre prospective observational cohort of multi-partner women with/without sex work and evaluated associated risk factors., Materials and Methods: Between January 2016 and June 2017, we offered free STI testing to women with multiple  sexual partners (three or more in the previous 12 months), with follow-up examinations every 6 months. We used multiplex polymerase chain-reaction testing (for Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Mycoplasma genitalium) for pooled swabs (pharynx, urethra/vagina, anus), and antibody tests for human immunodeficiency virus (HIV) and Treponema pallidum at every visit, and for hepatitis B and C at baseline., Results: We screened 490 female sex workers (FSWs), including 17 trans women, and 92 other multi-partner women. More than half reported a steady partner. Previously undiagnosed HIV was found in 0.2% vs 0.0%, respectively, and T. pallidum antibodies in 5.9% vs 0.0%. STIs requiring antibiotic treatment comprised: active syphilis 1.2% vs 0.0%; N. gonorrhoeae 4.9% vs 0.0%; C. trachomatis 6.3% vs 5.4%, T. vaginalis 10.4% vs 0.0%; M. genitalium 6.7% vs 6.5%. One in four FSWs vs one in nine other women had one or more of these STIs at baseline. 15.8% vs 3.8% had a history of hepatitis B, 45.5% vs 22.8% had no immunity (HBs-AB <10 IU/l). Two FSWs had hepatitis C virus antibodies (0.4%) without concurrent HIV infection. Non-condom-use (last three months) for anal/vaginal sex was not associated with STIs. Independent risk factors were group sex (adjusted odds ratio [aOR] 2.1, 95% confidence interval [CI] 1.1–4.0), age less than 25 (aOR 3.7, 95% CI 1.6–8.9), and being active in sex work for less than 1 year (aOR 2.7, 95% CI 1.3–5.3)., Conclusion: HIV and HCV do not appear to pose a major public health problem among FSWs in Switzerland, whereas vaccination against HBV should be promoted. FSWs showed high rates of STIs requiring treatment to reduce transmission to clients and/or steady partners. FSWs should be offered low-cost or free STI screening as a public health priority.

Objectives: In Switzerland, universal health insurance does not cover any routine testing for sexually transmitted infections (STIs), not even in individuals at high risk, and extra-genital swabbing is not standard of care. We determined the prevalence and incidence of human immunodeficiency virus (HIV), viral hepatitis and non-viral STIs in a multicentre prospective observational cohort of multi-partner men who have sex with men (MSM) and other men., Materials and Methods: Between January 2016 and June 2017, we offered free STI testing to all men with multiple  sexual partners (three or more in the previous 12 months), with follow-up examinations every 6 months. We used multiplex polymerase chain-reaction testing (for Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Mycoplasma genitalium) on pooled swabs (pharynx, urethra/vagina, anus), and antibody tests for HIV and Treponema pallidum at every visit, and for hepatitis B/C at baseline., Results: We screened 779 multi-partner MSM and 92 other men. Previously undiagnosed HIV was found in 0.5% vs 0.0%, respectively and T. pallidum antibodies in 15.3% vs 1.1%. STIs requiring antibiotic treatment comprised: active syphilis 1.7% vs 0.0%; N. gonorrhoeae 10.3% vs 0.0%; C. trachomatis 8.7% vs 1.1%. One in four MSM versus 1 in 100 other multi-partner men had any of these three STIs at baseline. 10.4% vs 1.3% had a history of hepatitis B, 31.9% vs 47.3% had no immunity (HBs-AB <10 IU/l). Ten MSM had HCV antibodies (1.4%), with 8 out of the 10 being MSM with HIV; HCV seroprevalence was 0.3% among HIV-negative MSM. In MSM, incidence of the three bacterial STIs was 25.5 per year over 333 person years of follow-up, HIV incidence was 0.3%. Non-condom-use (in the last 3 months) for anal/vaginal sex was not associated with STIs. Independent risk factors were sex with men (adjusted odds ratio [aOR] 16.4) and the number of sexual partners (aOR 2.3 for >20)., Conclusion: Among MSM, but not among other multi-partner men, STIs, mostly asymptomatic, are common. Given the high risk of onward transmission, low-cost or free routine screening of multi-partner MSM is a public health priority.

Objectives: There is no estimate of the current number of men who have sex with men (MSM) in Switzerland, or of their geographical distribution. We aimed to (1) estimate MSM concentration factors and population sizes for 83 Swiss postal code areas (PCA), including the nine largest Swiss cities, and (2) calculate MSM-specific local HIV prevalence and yearly rates of diagnosed HIV, hepatitis C virus (HCV), syphilis and gonorrhoea., Methods: We triangulated data from general population estimates, MSM online surveys, published data on HIV prevalence and Swiss notification data for HIV and STDs. We compared two different formulae for the estimation of local MSM populations and calculated Bayesian 95%-credible-intervals (CrI) for each PCA., Results: Across Switzerland, we estimate the MSM population aged 15-64 at roughly 80 000 men (95% CrI 64 000-96 000). (1) MSM in Switzerland were most concentrated in the five largest cities of Zurich, Geneva, Lausanne, Bern and Basel. (2) We estimate that in 2012, 6300 MSM, or 8.0%, were living with HIV, both diagnosed and undiagnosed and 1700 MSM, or 2.2%, had non-suppressed HIV infection. Between 2010 and 2013, average yearly rates of diagnosed HIV, HCV, syphilis and gonorrhoea were 0.3%, 0.02%, 0.4 % and 0.4 %, respectively., Conclusions: Combining general population data, MSM online surveys and notification data allows the calculation of realistic estimates of local MSM populations and thus proportions of MSM with diagnosed HIV and other STIs, with implications for prevention planning, commissioning of health services and counselling MSM on HIV/STI risk. Our methodology for Switzerland is transferable to other countries with similar data sources., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)