Dr. Alex Marzel

Dr. Alex Marzel


“Make everything as simple as possible, but not simpler.”

-Albert Einstein

I am passionate about medical research, project management and data analysis across all fields of medicine. With more than ten years of experience in analyzing and publishing medical and biological data I am excited about new encounters and collaborations. I strongly believe that in medical research the clinical question should receive the main focus, not the complexity of the analysis. Whether a small observational study, a large cohort or a multicenter clinical trial – my guiding principles are scientific rigor, pragmatism and simplicity. Finally, my experience as an academic editor at Swiss Medical Weekly helps me to identify the strong and the weak points of each project hence facilitating a faster publication in top medical journals.
  • Clinical project management and monitoring
  • Medical writing
  • Literature review
  • Regulatory submissions
  • Data analysis & data management
  • Reporting and visualization
  • PhD in Epidemiology and Biostatistics, 2018

    Zurich University

  • MSc in Epidemiology and Preventive Medicine, 2014

    Tel Aviv University

  • BA in Sociology and Anthropology, 2009

    Tel Aviv University


R programming


REDCap / Filemaker





  • Medical writing
  • Literature review
  • Study design and planning
  • Writing of Clinical Study Protocols (CSP)
  • Clinical project management
  • Statistical analysis and reporting of deliverables
  • Mixed-model regression, Survival analysis
  • Support of master, MD and PhD dissertations
  • Ad-hoc production of tables and figures
  • Data management and REDCap databases
  • Manuscript review and scientific editing
  • Ethic protocols including BASEC submission


Roger D Kouyos, Peter Rusert, Claus Kadelka, Michael Huber, Alex Marzel, Hanna Ebner, Merle Schanz, Thomas Liechti, Nikolas Friedrich, Dominique L Braun, et al. Tracing hiv-1 strains that imprint broadly neutralizing antibody responses. Nature, 561(7723):406–410, 2018.

Chaudron SE, Leemann C, Kusejko K, Nguyen H, Tschumi N, Marzel A, Huber M, Böni J, Perreau M, Klimkait T, Yerly S, Ramette A, Hirsch HH, Rauch A, Calmy A, Vernazza P, Bernasconi E, Cavassini M, Metzner KJ, Kouyos RD, Günthard HF; Swiss HIV Cohort Study. A Systematic Molecular Epidemiology Screen Reveals Numerous Human Immunodeficiency Virus (HIV) Type 1 Superinfections in the Swiss HIV Cohort Study. The Journal of Infectious Diseases (JID). 2022 Sep 28;226(7):1256-1266. doi: 10.1093/infdis/jiac166. PMID: 35485458.

Andresen S, Balakrishna S, Mugglin C, Schmidt AJ, Braun DL, Marzel A, Doco Lecompte T, Darling KE, Roth JA, Schmid P, Bernasconi E, Günthard HF, Rauch A, Kouyos RD, Salazar-Vizcaya L; Swiss HIV Cohort Study. Unsupervised machine learning predicts future sexual behaviour and sexually transmitted infections among HIV-positive men who have sex with men. PLOS Computational Biology. 2022 Oct 27;18(10):e1010559. doi: 10.1371/journal.pcbi.1010559. PMID: 36302041; PMCID: PMC9642906.

Alex Marzel, Hans-Kaspar Schwyzer, Christoph Kolling, Fabrizio Moro, Matthias Flury, Michael C Glanzmann, Christian Jung, Barbara Wirth, Beatrice Weber, Beat Simmen, et al. The schulthess local shoulder arthroplasty registry (sar): cohort profile. BMJ open, 10(11):e040591, 2020.

Hans-Kaspar Schwyzer, Alex Marzel, Barbara Wirth, Dominik Rickenbacher, Matthias Flury, Christian Schoch, Mark Tauber, Daniel Rzepka, Lars Lehmann, Sven Lichtenberg, et al. Short-term safety, function, and quality of life in patients treated with univers revers prosthesis: a multicenter 2-year follow-up case series. Journal of Shoulder and Elbow Surgery, 29(11):2282–2291, 2020.

Alex Marzel, Mohaned Shilaih, Wan-Lin Yang, Jürg Böni, Sabine Yerly, Thomas Klimkait, Vincent Aubert, Dominique L Braun, Alexandra Calmy, Hansjakob Furrer, et al. Hiv-1 transmission during recent infection and during treatment interruptions as major drivers of new infections in the swiss hiv cohort study. Clinical Infectious Diseases, 62(1):115–122, 2016.

A Marzel, Mohaned Shilaih, T Turk, Nottania K Campbell, W-L Yang, J Böni, S Yerly, T Klimkait, Vincent Aubert, Hansjakob Furrer, et al. Mining for pairs: shared clinic visit dates identify steady hiv-positive partnerships. HIV medicine, 18(9):667–676, 2017.

Alex Marzel, Prerak T Desai, Alina Goren, Yosef Ilan Schorr, Israel Nissan, Steffen Porwollik, Lea Valinsky, Michael McClelland, Galia Rahav, and Ohad Gal-Mor. Persistent infections by nontyphoidal salmonella in humans: epidemiology and genetics.Clinical Infectious Diseases, 62(7):879–886, 2016.

Mohaned Shilaih, Alex Marzel, Dominique L Braun, Alexandra U Scherrer, Helen Kovari, Jim Young, Alexandra Calmy, Katharine Darling, Manuel Battegay, Matthias Hoffmann, et al. Factors associated with syphilis incidence in the hiv-infected in the era of highly active antiretrovirals. Medicine, 96(2), 2017.

Alex Marzel, Henriette Heinrich, Lukas Schilliger, Jan S Fehr, Huldrych F Günthard, Roger Kouyos, and Silvana K Rampini. Prescription of postexposure prophylaxis for hiv-1 in the emergency room: Correct transmission risk assessment remains challenging. JAIDS Journal of Acquired Immune Deficiency Syndromes, 74(4):359–366, 2017.

Mohaned Shilaih, Alex Marzel, Wan Lin Yang, Alexandra U Scherrer, Jörg Schüpbach, Jürg Böni, Sabine Yerly, Hans H Hirsch, Vincent Aubert, Matthias Cavassini, et al. Genotypic resistance tests sequences reveal the role of marginalized populations in hiv-1 transmission in switzerland. Scientific reports, 6(1):1–10, 2016.

Mohaned Shilaih, Alex Marzel, Alexandra U Scherrer, Dominique L Braun, Helen Kovari, Mathieu Rougemont, Katharine Darling, Manuel Battegay, Matthias Hoffmann, Enos Bernasconi, et al. Dually active hiv/hbv antiretrovirals as protection against incident hepatitis b infections: potential for prophylaxis. The Journal of infectious diseases, 214(4):599–606, 2016.

Alex Marzel, Katharina Kusejko, Rainer Weber, Philip Bruggmann, Andri Rauch, Jan A Roth, Enos Bernasconi, Alexandra Calmy, Matthias Cavassini, Matthias Hoffmann, et al. The cumulative impact of harm reduction on the swiss hiv epidemic: Cohort study, mathematical model, and phylogenetic analysis. In Open forum infectious diseases, volume 5, page ofy078. Oxford University Press US, 2018.

Alex Marzel, Prerak T Desai, Israel Nissan, Yosef Ilan Schorr, Jotham Suez, Lea Valinsky, Abraham Reisfeld, Vered Agmon, Jean Guard, Michael McClelland, et al. Integrative analysis of salmonellosis in israel reveals association of salmonella enterica serovar 9, 12: l, v:- with extraintestinal infections, dissemination of endemic s. enterica serovar typhimurium dt104 biotypes, and severe underreporting of outbreaks. Journal of clinical microbiology, 52(6):2078–2088, 2014.

Richard Mansky, Alex Marzel, E John Orav, Patricia O Chocano-Bedoya, Patricia Grünheid, Michèle Mattle, Gregor Freystätter, HB Stähelin, Andreas Egli, and Heike A Bischoff-Ferrari. Playing a musical instrument is associated with slower cognitive decline in community-dwelling older adults. Aging clinical and experimental research, pages 1–8, 2020.

Katharina Kusejko, Alex Marzel, Huyen Nguyen, Sandra E Chaudron, Nadine Bachmann, Rainer Weber, Philip Bruggmann, Jan A Roth, Enos Bernasconi, Alexandra Calmy, et al. Differences in social and mental well-being of long-term survivors among people who inject drugs and other participants in the swiss hiv cohort study: 1980-2018. Antiviral therapy, 2020.

Alenka Gugger, Alex Marzel, E John Orav, Walter C Willett, Bess Dawson-Hughes, Robert Theiler, Gregor Freystätter, Andreas Egli, and Heike A Bischoff-Ferrari. Effect of monthly high-dose vitamin d on mental health in older adults: secondary analysis of a rct. Journal of the American Geriatrics Society, 67(6):1211–1217, 2019.

Jerra Stemmle, Alex Marzel, Patricia O Chocano-Bedoya, E John Orav, Bess Dawson-Hughes, Gregor Freystaetter, Andreas Egli, Robert Theiler, Hannes B Staehelin, and Heike A Bischoff-Ferrari. Effect of 800 iu versus 2000 iu vitamin d3 with or without a simple home exercise program on functional recovery after hip fracture: a randomized controlled trial. Journal of the American Medical Directors Association, 20(5):530–536, 2019.

K Kusejko, A Marzel, B Hampel, N Bachmann, H Nguyen, J Fehr, DL Braun, M Battegay, Enos Bernasconi, Alexandra Calmy, et al. Quantifying the drivers of hiv transmission and prevention in men who have sex with men: a population model-based analysis in switzerland. HIV medicine, 19(10):688–697, 2018.

Herbert A Mbunkah, Alex Marzel, Stefan Schmutz, Yik Lim Kok, Osvaldo Zagordi, Mohaned Shilaih, Ndi N Nsanwe, Eyongetah T Mbu, Lydia M Besong, Bella A Sama, et al. Low prevalence of transmitted hiv-1 drug resistance detected by a dried blood spot (dbs)-based next-generation sequencing (ngs) method in newly diagnosed individuals in cameroon in the years 2015–16. Journal of Antimicrobial Chemotherapy, 73(7):1917–1929, 2018.

Alex Marzel, Roger D Kouyos, Sara Reinschmidt, Katharina Balzer, Fabienne Garon, Monica Spitaleri, Nicolas Matthes, Paolo Suter, Rainer Weber, Cornelia Staehelin, et al. Dietary patterns and physical activity correlate with total cholesterol independently of lipid-lowering drugs and antiretroviral therapy in aging people living with human immunodeficiency virus. In Open forum infectious diseases, volume 5, page ofy067. Oxford University Press US, 2018.

K Kusejko, A Marzel, H Nguyen, SE Chaudron, N Bachmann, R Weber, P Bruggmann, JA Roth, E Bernasconi, A Calmy, et al. Differences in social and mental well-being of long-term survivors among people who inject drugs and other participants in the swiss hiv cohort study: 1980-201. In HIV MEDICINE, volume 20, pages 202–202. WILEY 111 RIVER ST, HOBOKEN 07030-5774, NJ USA, 2019.

Dominique L Braun, Alex Marzel, Daniela Steffens, Peter W Schreiber, Christina Grube, Alexandra U Scherrer, Roger D Kouyos, and Huldrych F Günthard. High rates of subsequent asymptomatic stis and risky sexual behavior in patients initially presenting with primary hiv-1 infection. Clinical Infectious Diseases, 2017.

Frederic Bertels, Alex Marzel, Gabriel Leventhal, Venelin Mitov, Jacques Fellay, Huldrych F Günthard, Jürg Böni, Sabine Yerly, Thomas Klimkait, Vincent Aubert, et al. Dissecting hiv virulence: heritability of setpoint viral load, cd4+ t-cell decline, and per-parasite pathogenicity. Molecular biology and evolution, 35(1):27–37, 2018.

Frédérique Hovaguimian, Huldrych F Günthard, Christoph Hauser, Anna Conen, Enos Bernasconi, Alexandra Calmy, Matthias Cavassini, Marco Seneghini, Alex Marzel, Henriette Heinrich, et al. Data linkage to evaluate the long-term risk of hiv infection in individuals seeking post-exposure prophylaxis. Nature Communications, 12(1):1–8, 2021.

David Endell, Laurent Audigé, Alexandra Grob, Hans-Kaspar Schwyzer, Michael Glanzmann, Alex Marzel, and Markus Scheibel. Impact of sports activity on medium-term clinical and radiological outcome after reverse shoulder arthroplasty in cuff deficient arthropathy; an institutional register-based analysis. Journal of Clinical Medicine, 10(4):828, 2021.

Alexandra Grob, Florian Freislederer, Alex Marzel, Laurent Audigé, Hans-Kaspar Schwyzer, and Markus Scheibel. Glenoid component loosening in anatomic total shoulder arthroplasty: Association between radiological predictors and clinical parameters—an observational study. Journal of Clinical Medicine, 10(2):234, 2021.

A Grob, F Freislederer, L Audigé, A Marzel, HK Schwyzer, and M Scheibel. Glenoidale implantatlockerung in der anatomischen schultertotalendoprothetik-eine beobachtungsstudie über den zusammenhang radiologischer prädiktoren einer klinischen dekompensation. Zeitschrift für Orthopädie und Unfallchirurgie, 158(S 01), 2020.

F Freislederer, F Toft, L Audige, A Marzel, D Endell, HK Schwyzer, F Moro, and M Scheibel. Klinischer und radiologischer vergleich von grammont-design (155°) versus lateralisierter inverser schultertotalendoprothese (135°) bei defektarthropathie. Zeitschrift für Orthopädie und Unfallchirurgie, 158(S 01):DKOU20–767, 2020.

Philip E Tarr, Bruno Ledergerber, Alexandra Calmy, Thanh Doco-Lecompte, Isabella C Schoepf, Alex Marzel, Rainer Weber, Philipp A Kaufmann, René Nkoulou, Ronny R Buechel, et al. Longitudinal progression of subclinical coronary atherosclerosis in swiss hiv-positive compared with hiv-negative persons undergoing coronary calcium score scan and ct angiography. In Open forum infectious diseases, volume 7, page ofaa438. Oxford University Press US, 2020.

Helen Kovari, Alexandra Calmy, Thanh Doco-Lecompte, René Nkoulou, Alex Marzel, Rainer Weber, Philipp A Kaufmann, Ronny R Buechel, Bruno Ledergerber, Philip E Tarr, et al. Antiretroviral drugs associated with subclinical coronary artery disease in the swiss human immunodeficiency virus cohort study. Clinical Infectious Diseases, 70(5):884–889, 2020.

Katharina Kusejko, Claus Kadelka, Alex Marzel, Manuel Battegay, Enos Bernasconi, Alexandra Calmy, Matthias Cavassini, Matthias Hoffmann, Jürg Böni, Sabine Yerly, et al. Inferring the age difference in hiv transmission pairs by applying phylogenetic methods on the hiv transmission network of the swiss hiv cohort study. Virus evolution, 4(2):vey024, 2018.

Philip E Tarr, Bruno Ledergerber, Alexandra Calmy, Thanh Doco-Lecompte, Alex Marzel, Rainer Weber, Philipp A Kaufmann, René Nkoulou, Ronny R Buechel, Helen Kovari, et al. Subclinical coronary artery disease in swiss hiv-positive and hiv-negative persons. European heart journal, 39(23):2147–2154, 2018.

Nadine Bachmann, Teja Turk, Claus Kadelka, Alex Marzel, Mohaned Shilaih, Jürg Böni, Vincent Aubert, Thomas Klimkait, Gabriel E Leventhal, Huldrych F Günthard, et al. Parent-offspring regression to estimate the heritability of an hiv-1 trait in a realistic setup. Retrovirology, 14(1):1–10, 2017.

Mohaned Shilaih, Daniel C Angst, Alex Marzel, Sebastian Bonhoeffer, Huldrych F Günthard, and Roger D Kouyos. Short communication antibacterial effects of antiretrovirals, potential implications for microbiome studies in hiv. Antiviral therapy, 23:91–94, 2018.

Michael McClelland, Alex Marzel, Prerak T Desai, and Ohad Gal-Mor. Reply to yue. Clinical Infectious Diseases, 62(10):1326–1327, 2016.

Jotham Suez, Steffen Porwollik, Amir Dagan, Alex Marzel, Yosef Ilan Schorr, Prerak T Desai, Vered Agmon, Michael McClelland, Galia Rahav, and Ohad Gal-Mor. Virulence gene profiling and pathogenicity characterization of non-typhoidal salmonella accounted for invasive disease in humans. PloS one, 8(3):e58449, 2013.

D Ben-David, R Kordevani, N Keller, I Tal, A Marzel, O Gal-Mor, Y Maor, and G Rahav. Outcome of carbapenem resistant klebsiella pneumoniae bloodstream infections. Clinical Microbiology and Infection, 18(1):54–60, 2012.