Our Statement to the Response of Bertisch et al. 2023 “Letter to the Editor”
News — 26.10.2023
Hepatitis C epidemiology in Switzerland: we need a better data basis and surveillance system
We have taken note of the response by Bertisch et al. 2023 (1) to our Letter to the Editor. (2) Unfortunately, their response contains misleading information and misinterpretation of scientific data. We stand by our assessment that the authors fail to sufficiently discuss the reliability and validity of the publications in their review, as stated in our “Letter to the Editor”(2) and our detailed list of concerns(3), available at: http://bit.ly/40dY1vy
Epidemiological data are almost always subject to limitations. These are: incomplete data collection, limited representativeness due to selection issues and thereby lack of generalisability, high variability of the primary data leading to a high variance, uncertainty of the point estimates and often lack of statistical power. Swiss Hepatitis, therefore, welcomes open and fact-based discussions. We need a constructive dialogue based on scientific standards.
That said, we would like to point out some mistakes and misleading interpretations by Bertisch et al. Despite citing many publications, Bertisch et al. repeatedly fail to reference the newest publications: They did not include the study by Bihl et al. 2022 (4) (which is not our “own modelling study” (1) as wrongly claimed by the authors), in the discussion of their review. (5)(3) Another example is a publication modelling the burden of disease. Bertisch et al. 2023 try to underline their argument about wrong projections of increasing mortality with the modelling study from the year 2015. (6) It slipped the author's attention that this publication was updated: The renewed calculations do not project an increase in mortality as claimed by Bertisch et al. (7)
The statement that the Swiss notification system data allows detecting viraemic Hepatitis C Virus (HCV) cases in Switzerland in almost all cases is over-optimistic and misleading. The virological diagnostic labs in Switzerland doubt that all HCV RNA test results are reported to the Federal Office of Public Health (FOPH) and linked to positive antibody test results. To improve the current notification system, additional measures similar to HIV notifications, would need to be implemented.
This example shows that we need to be aware of structural and procedural limitations when interpreting available data and must contextualise this information accordingly: The current HCV notification system renders an incomplete picture and does not reliably reflect the actual prevalence of this disease. We would need more data and an expert consensus process, including the main HCV and public health experts in Switzerland with longstanding experience in the field, to renew estimates about HCV prevalence in Switzerland.
There are relevant gaps concerning HCV prevalence data in Switzerland: A large population prevalence study is missing, and data on HCV prevalence are primarily available from particular settings with a bias towards optimised care(8), which limits generalizability. In addition, we lack reliable data on the burden of disease and mortality caused by HCV. (9)
Switzerland needs a better surveillance and response system to monitor the situation continuously and react promptly. Data about positive tests (HCV antibody and HCV RNA), treatment numbers, treatment settings, and reliable and constantly updated data about morbidity and mortality should be available. Collaboration with the cancer registry would be necessary. We hope the new HIV and hepatitis programme (NAPS) that should be implemented starting in January 2024 will provide the basis for these needs.
Last, but not least, Bertisch et al. 2023 wrongly claim that Swiss Hepatitis previously mandated the CDA Foundation. While we know and appreciate the essential work of the internationally renowned CDA Foundation, their publications were never ordered or financed by Swiss Hepatitis. CDA works directly with hepatitis experts in Switzerland.
In conclusion, we reaffirm our assessment that Bertisch et al.'s publications do not provide enough evidence to revise other recent HCV prevalence estimates in Switzerland or to assess compliance with WHO elimination targets. More work is needed to get a clear picture of the current epidemiology and burden of disease of hepatitis C in Switzerland.
Bertisch B, Schaetti C, Schmid P, Peter L, Vernazza P, Isler M, et al. Letter to the Editor: Chronic hepatitis C virus infections in Switzerland in 2020: Lower than expected and suggesting achievement of WHO elimination targets. J Viral Hepat. 2023;
Blach S, Bregenzer A, Bruggmann P, Cerny A, Maeschli B, Negro F, et al. Assessing the hepatitis C epidemiology in Switzerland: it’s not that trivial. J Viral Hepat. 2023;00:1–2.
Swiss Hepatitis. List of detailed concerns [Internet]. 2023 [cited 2023 Oct 21]. Available from: https://hepatitis-schweiz.ch/data/download/81680/List-of-concerns-re-Bertisch-et-al-2023_17_07_23.pdf
Bihl F, Bruggmann P, Castro Batänjer E, Dufour J-F, Lavanchy D, Müllhaupt B, et al. HCV disease burden and population segments in Switzerland. Liver Int. 2022;42:330–9.
Bertisch B, Schaetti C, Schmid P, Peter L, Vernazza P, Isler M, et al. Chronic hepatitis C virus infections in Switzerland in 2020: Lower than expected and suggesting achievement of WHO elimination targets. J Viral Hepat. 2023;30(8):667–84.
Müllhaupt B, Bruggmann P, Bihl F, Blach S, Lavanchy D, Razavi H, et al. Modeling the health and economic burden of hepatitis C virus in Switzerland. PLoS One. 2015 Jun 24;10(6).
Müllhaupt B, Bruggmann P, Bihl F, Blach S, Lavanchy D, Razavi H, et al. Progress toward implementing the Swiss Hepatitis Strategy: Is HCV elimination possible by 2030? PLoS One. 2018;13(12).
Bregenzer A, Conen A, Knuchel J, Friedl. A, Eigenmann F, Näf M, et al. Management of hepatitis C in decentralised versus centralised drug substitution programmes and minimally invasive point-of-care tests to close gaps in the HCV cascade. Swiss Med Wkly. 2017;Swiss Med.
Keiser O, Giudici F, Müllhaupt B, Junker C, Dufour JF, Moradpour D, et al. Trends in hepatitis C-related mortality in Switzerland. J Viral Hepat. 2018;25(2):152–60.