Michael is a Professor for Biostatistics working under the German Research Foundations Heisenberg Program at the Department of Statistics, Ludwig-Maximilians-Universität (LMU) München, Germany. He is also an honorary senior lecturer at the University of Cape Town, South Africa, where he has been working for more than a decade as part of IeDEA-SA. His research interests include the development and application of modern causal inference methods to challenging longitudinal observational databases, for example in the context missing data, survival data and for continuous exposures. He is interested in pediatric HIV research on both optimal treatment strategies and antiretroviral target concentrations.
Senior Research Officer, UCT
Gem Patten
Gem is an epidemiologist with a PhD in Public Health. Her research interests include topics related to the public health approach to treating HIV in Southern Africa, including describing long-term trends in the characteristics and treatment outcomes among people with HIV receiving treatment. Her areas of research have included the implementation of differentiated service delivery models of care, CD4 and viral load monitoring strategies for antiretroviral therapy programmes and more recently, advanced HIV disease and treatment failure in the era of widespread access to antiretroviral therapy, with a particular focus on treatment options for paediatric and adolescent populations.
Senior research officer, UCT
Dr Patience Nyakato
Dr Patience Nyakato is a public health researcher with a PhD in Public Health (Epidemiology and Biostatistics) from the University of Cape Town and a Master’s degree in Medical Statistics from the London School of Hygiene and Tropical Medicine. Her research focuses on the analysis of longitudinal data to evaluate long-term engagement in care among children, adolescents, and young adults living with HIV (CAYHIV). Currently, her research is focused on investigating the impact of care interruptions on long-term health outcomes and develops evidence-based recommendations to enhance medication adherence, clinic visit compliance, retention in care, and virologic suppression. Dr. Patience is also interested in exploring data science methodologies to address challenges in accessing HIV treatment and care, contributing to innovative strategies in public health research.
Senior Data Scientist, UCT
Nicky Maxwell
Nicky is the Senior Data Scientist for the IeDEA-SA South Africa cohort, a role she has held since joining the collaboration in 2007. Prior to that, she worked as the Data Manager for the Khayelitsha cohort, following her return from the UK, where she spent several years as a Surveillance Officer with the Health Protection Agency. Nicky has a background in pediatric nursing and brings a passion for tackling complex data challenges. She is also a keen Stata enthusiast, always eager to explore new ways of working with data.
Epidemiologist & Modeler, UCT
Dr Leigh Johnson
Leigh is an epidemiologist and actuary, with a particular interest in the modelling of HIV and other diseases. He leads the development of the Thembisa model, an integrated HIV, TB and demographic model for South Africa. He also leads the development of MicroCOSM, an agent-based model of the social determinants of HIV and other STIs in South Africa. He is a co-chair of the UNAIDS Reference Group on Estimates, Modelling and Projections, and is a member of the editorial boards of ‘Infectious Disease Modelling’ and ‘Journal of the International AIDS Society’.
Senior Research Fellow, ISPM
Dr Andreas Haas
Andreas Haas received a Master of Arts in Social Research from Goldsmiths, University of London, in 2011, and a PhD in Health Sciences (Epidemiology and Biostatistics) from the University of Bern in 2016. He completed postdoctoral training in HIV epidemiology and global mental health at Columbia University in 2018–2019 and obtained his Habilitation (venia docendi) in Epidemiology from the Faculty of Medicine at the University of Bern in 2023.
Since 2021, he has been Head of the Mental Health Research Group at the Institute of Social and Preventive Medicine (ISPM), University of Bern, and a Research Fellow in the HIV Research Group at ISPM since 2011. His research focuses on psychiatric and HIV epidemiology in sub-Saharan Africa.
Senior Research Fellow, ISPM
Prof Lukas Fenner
Lukas is an epidemiologist and public health expert. His research focuses on infectious disease epidemiology, with a particular emphasis on the epidemiology of tuberculosis and HIV at the intersection of clinical and molecular data. He also has a keen interest in tuberculosis and respiratory virus transmission. As a senior research scientist, he has led multiregional projects on tuberculosis and HIV in large international collaborations (ART-LINC, IeDEA, Swiss HIV Cohort Study, Collaboration of Observational HIV Epidemiological Research in Europe) and conducted molecular epidemiological studies in Switzerland and sub-Saharan Africa. During a two-year stay in Tanzania, he led a team of physicians and scientists at the Ifakara Health Institute, gaining extensive field experience as a scientific project leader and tuberculosis team leader. He later served as a chief cantonal public health officer in Switzerland, significantly contributing to the public health response during the COVID-19 pandemic, and applying epidemiological principles in practice. Now back at the University of Bern, he leads the tuberculosis projects within IeDEA Southern Africa, including a multi-cohort study spanning five tuberculosis cohorts in a region disproportionately affected by the tuberculosis and HIV epidemics. His experience enables him to bridge theory and practice, connecting academia with public health challenges.
Senior Data Manager, ISPM
Cam Ha Dao Ostinelli
Cam Ha is a Senior Data Manager with a background in software engineering and a strong focus in data science. She has built a robust career as a data expert, specializing in data architecture, integration, data visualization and governance. Since joining the consortium she has significantly raised standards of data collection and data quality through enhanced process, monitoring and customized reporting tools. With her technical expertise, she also supports research study design to ensure high quality and efficiency. Passionate about translating technical solutions into practical research values, she helps multidisciplinary teams trust and leverage their data. Most recently, she successfully led the development of a universal data quality tool for longitudinal studies and cohort data.
She is reponsible for data of IeDEA-SA cohorts in Lesotho, Malawi, Mozambique, Zambia and Zimbabwe and works in close collaboration with the Data Manager at UCT who is responsible for cohorts within South Africa.
Epidemiologist, UCT
Prof Andrew Boulle
Andrew was co-Principal Investigator of IeDEA-SA from its inception until 2011. During this time, he completed his PhD on the effectiveness of ART in Khayelitsha and in the Western Cape, following adults for up to five years on ART and examining temporal trends over seven years, during a time when ART services expanded dramatically in the province. Andrew currently holds a joint appointment as Associate Professor in the Division of Public Health Medicine, UCT, and as a Public Health specialist in the Health Impact Assessment Directorate of the Western Cape Department of Health.
Senior Research Officer, ISPM
Dr Marie Ballif
Marie Ballif holds a PhD and an MSc in Public Health and brings over 15 years of experience as a senior researcher in public and global health, with a particular focus on HIV and tuberculosis. Passionate about tackling disparities, she applies her transdisciplinary expertise in public health, epidemiology, and microbiology to advance equitable healthcare access.
Program Manager, ISPM
Dr Per von Groote
Per Maximilian von Groote is the acting Program Manager of the International Epidemiological Database to Evaluate Aids, Southern Africa (IeDEA SA) research consortium and is based at the Institute of Social and Preventive Medicine (ISPM), University of Bern. Per von Groote worked on numerous projects including research into social inequalities in functioning and disability, rehabilitation systems and services, and international public health policy, and is an executive editor of the WHO Report International Perspectives on Spinal Cord Injury. In these roles he developed an expertise in implementation research, specifically looking at the implementation of WHO global public health recommendations into national contexts. Among other participatory, stakeholder-driven and evidence-based implementation strategy development, application, monitoring and evaluation methods he conducted stakeholder dialogues in many countries including Germany, Romania, Sri Lanka, and Malaysia. He holds a Magister Artium in Political Sciences and History, a Master of European Politics and Government and a PhD in Health Science and Health Policy with a focus on implementation research.
Researcher, UCT
Dr Reneé de Waal
Reneé de Waal is an epidemiologist at the UCT data centre. She has a background in clinical pharmacology and experience in HIV care. Her research interests include implementation, safety, and effectiveness of antiretroviral drugs, in children and adults.
Statistician, ISPM
Dr Veronika Whitesell
Veronika is a senior statistician with a PhD in biostatistics from the University of Washington. Her work focuses on applying advanced statistical methods to HIV epidemiology and global health. She has been with ISPM since 2016 and joined the IeDEA-SA team in 2019, contributing to a range of studies—from Dolutegravir resistance to authorship inequalities and mental health. Veronika also supports mentoring and capacity building in statistical methods.
Researcher, UCT
Dr Mpho Tlali
I am a clinician with an interest in HIV research. I have a Master’s degree in Tropical Medicine and International Health from the London School of Hygiene and Tropical Medicine. I have taken a leadership role as part of my research on two large multinational, multicentre cohort studies: one to evaluate targeted empirical TB treatment based on novel algorithms for early TB diagnosis in HIV-positive adults with advanced HIV disease and, another to explore the feasibility of implementing a “Universal Test and Treat” programme within a correctional services setting. My current role is to contribute to research on the impact of substance abuse amongst HIV positive adolescents and young adults and explore measures that might help mitigate those effects. I am passionate about enabling HIV prevention in marginalised communities in the African context and making it a reality.
Senior Researcher, UCT
Dr Kim Anderson
Kim Anderson is a clinical epidemiologist at the UCT data centre. She has a clinical background in paediatic and adolescent HIV medicine. Her research areas of interest include health outcomes in children and adolescents with perinatally-acquired HIV, morbidity in HIV-exposed uninfected children and prevention of vertical transmission of HIV. Kim chairs the Paediatric Working Group for the global IeDEA consortium.
Statistical Researcher, UCT
Dr Reshma Kassanjee
Reshma is a biostatistician who is passionate about applying her training in both mathematical statistics and computational and applied mathematics to public health. She joined the IeDEA-SA team in 2019, after several years working as a researcher and consultant, in a diversity of environments and application areas. She has always had an interest in HIV, and her PhD (2014) focused on developing novel methods and practical tools that are still widely used globally for estimating HIV incidence. In line with her goal of developing methods and generating results that inform individual- and population-level decision making, since joining the IeDEA-SA team, she has led multi-regional analyses in support of the UNAIDS Reference Group’s efforts to produce global annual HIV statistics. During the COVID-19 pandemic, she led analyses of vaccine effectiveness that were used to guide decisions in South Africa. Reshma provides statistical input on multiple projects within IeDEA-SA.
* Joint United Nations Programme on HIV/AIDS Reference Group on Estimates, Modelling and Projections
Project Manager, UCT
Wendy Wiemers
Wendy has a BCom and an Honours degree in Social Policy and Management.
She has nearly 25 years’ experience of operational management experience in the NPO and academic sector, including management of clinical research sites for the UCT Clinical Trials Unit before starting at CIDER. At CIDER, Ms Wiemers is responsible for all financial and operational management of several large studies (budgets ~R20 million per year) with funders including National Institutes of Health, Wellcome Trust, European Union, South African Medical Research Council and Pharmaceutical companies.
Ms Wiemers is a real team player and has been an asset to co-ordinating activities both within projects and in CIDER overall. She took the initiative to volunteer to organize 2 large international meetings of our largest project, the IeDEA Southern Africa Cohort Collaboration.
Research Fellow, ISPM
Dr Katayoun Taghavi
Kati is a gynecologist by training and has completed her Fellowship with the Royal Australian and New Zealand College of Obstetricians and Gynecologists. She has learned greatly from diverse clinical experiences in New Zealand, USA, Italy, Switzerland, Ethiopia, and Iran. Cervical cancer screening has been a research interest of hers for some time. The burden of cervical cancer disproportionately affects women living in low-income countries and the high prevalence of HIV in many of these setting contributes to the problem. In August 2021, she completed her PhD with the ISPM IeDEA-SA team on cervical cancer screening in HIV positive women. She now looks forward to continuing some cancer related projects as well as exploring the relationship between sexually transmitted diseases and HIV.
Senior Data Scientist, UCT
Chido Chinogurei
Chido is enthusiastic about solving challenges involved with building and maintaining data pipelines from a variety of database systems with a keen focus on improving data quality to uncover patterns, trends and insights. His previous experience has been from Agincourt MRC/Wits Health Transition Research Unit, National Income Dynamics Study and the Centre for Actuarial Research. His background is in Mathematical Demography and Statistics.
Senior Research Officer, UCT
Dr Haroon Moolla
Haroon is a medical doctor and actuarial graduate. His areas of interest include mathematical modelling and outcomes related to antiretroviral treatment interruptions. He is currently a Fogarty clinical PhD fellow investigating the role of ART interruptions in the TB epidemic.
Research Fellow, ISPM
Dr Nathalie Fernández
Nathalie is an epidemiologist and environmental health professional. Her research interests are mainly focused on infectious diseases, epidemiology, and implementation research. She has expertise in viral hepatitis, tuberculosis, SARS-CoV-2, and evidence synthesis. Nathalie joined ISPM in 2022 after completing her PhD in Epidemiology at the Medical School Hannover (MHH) in collaboration with the Helmholtz Centre for Infection Research (HZI), Germany. She currently supports research teams working on Cancer, HIV, Hepatitis, and Tuberculosis.
Data Manager, UCT
Confidence Mothiba
Confidence is a qualified software developer with a Postgraduate Degree in Healthcare Technology Management and a National Diploma in Information Technology (Software Development), with a specialization in C++. He has a strong foundation in PHP application development, SQL, and database design and development.
With a passion for data and a keen interest in maintaining high data quality standards, Confidence has expanded his skill set through self-directed learning in R programming. He particularly enjoys building interactive dashboards using R Shiny to transform data into actionable insights.
In addition to his technical expertise, Confidence holds professional certificates in Project Management in Global Health and Leadership and Management in Health, both earned from the University of Washington, highlighting his interest in healthcare systems and global health initiatives.
His diverse background uniquely positions him at the intersection of software development, data analytics, and healthcare technology.
Program Management, ISPM
France Genin
France has an MA in Social Sciences and completed a joint CAS in DEI at the FHNW, ZHAW and the University of Basel in 2024. Her background is in Public Health and she has been working for several years as a Scientific Collaborator at the Federal Office of Public Health (FOPH), mostly on projects related mental health and health access equity. As of 2025 she is the Program Management Assistant for IeDEA-SA at ISPM.
Project Manager, UCT
Dr Shani de Beer
Shani has recently completed her PhD in Population Health as part of a cotutelle programme between the University of Cape Town and the University of Bristol. Her PhD thesis investigated infection-related hospitalisations and healthcare utilisation, by HIV-exposure status and maternal engagement in antiretroviral therapy, among children in the Western Cape, South Africa. During her PhD, she gained invaluable experience working with routine healthcare data from the Western Cape Provincial Health Data Centre. Shani is currently working as a UCT project manager for IeDEA-SA and a data analyst for CIDER.
Senior Research Officer, ISPM
Prof Matthias Egger
Prof. Egger has a long-standing interest in the clinical epidemiology of HIV, including HIV-related cancers and other co-morbidities, with over 20 years of experience in HIV observational cohort research. He was instrumental in establishing the Antiretroviral Therapy Cohort Collaboration (ART-CC) in the 2000s, and later the ART in Lower Income Countries (ART-LINC), to estimate prognosis of HIV-1 infected, treatment-naïve patients initiating combination ART. He is also involved in the large COHERE collaboration (Collaboration of Observational HIV Epidemiological Research in Europe) and the Swiss Tuberculosis Network. Together with colleagues from the London School of Tropical Medicine and Hygiene, Prof.Egger leads the mortality working group of the HIV Measurement, Surveillance & Evaluation Methods (MeSH).
Prof. Egger has served as co-Principal Investigator of IeDEA-SA since its inception in 2006. Under his leadership, IeDEA-SA project staff have served a key role in initiating and developing a joint collaboration between IeDEA global consortium and the WHO and UNAIDS. He has been Director of the Institute of Social and Preventive Medicine (ISPM) since 2002 and from January 2017, he will become the elected president of the Research Council of the Swiss National Science Foundation (SNSF).
Statistician, ISPM
Yann Ruffieux
Yann holds a MSc in Mathematical Engineering from the Ecole Polytechnique Fédérale de Lausanne (EPFL). He has been working at ISPM since 2016, and on IeDEA projects since 2019. Currently his main tasks involve statistical support and data management for the cancer and mental health groups at IeDEA-SA.
Senior Research Fellow, ISPM
Dr Nanina Anderegg
Nanina is an epidemiologist and mathematician whose work focuses on HIV and other sexually transmitted infections. She completed her PhD at ISPM within the IeDEA-SA collaboration, evaluating ART roll-out in sub-Saharan Africa with a focus on ART initiation, loss to follow-up, and mortality. After her PhD, she remained involved in IeDEA, supporting PhD students in Malawi and Zimbabwe, and also participated in the Swiss National COVID-19 Science Task Force’s data and modelling group. She then spent two years in South Africa at UCT on a Swiss National Science Foundation (SNSF) Postdoc.Mobility fellowship, focusing on improving mathematical modelling of HIV in key populations. Now back in Switzerland, based at ISPM and the University Hospital Zurich and supported by an SNSF Return.CH fellowship, she continues her work on HIV and is expanding her research to include other STIs.
Chief Research Officer and Director, CIDER
A/Prof Emma Kalk
Associate Professor Emma Kalk is a clinical epidemiologist and Director of the Centre for Integrated Data and Epidemiological Research (CIDER), School of Public Health, University of Cape Town. Her focus is on operational research in maternal and child health. Her current interests include pharmacovigilance and surveillance in pregnant and breast-feeding women with an emphasis on antiretroviral and anti-tuberculosis therapy. She manages the Pregnancy Exposure Registry in Cape Town (a sentinel-site of the South African Pregnancy Exposure Registry) which is supported by a larger population-level database. Dr Kalk is a founding member and current Director of the sub-Saharan African Congenital Anomalies Network (sSCAN).
Research Assistant, ISPM
Remo Schmutz
Remo joined ISPM in 2023 and is currently completing a Master’s degree in Biostatistics at the University of Zürich. He holds a Bachelor’s degree from the University of Bern, with a major in Psychology and a minor in Mathematics. At ISPM, he supports various research projects by carrying out data cleaning, -analysis, and -visualisation.
Statistician, LMU
Christoph Wiederkehr
Christoph joined the Department of Statistics at Ludwig-Maximilians-Universität (LMU) Munich in 2023 as a PhD candidate. He holds a Master’s degree in Statistics & Data Science and a Bachelor’s degree in Statistics with a minor in Business Administration, both from LMU Munich. His Master’s thesis focused on handling missing data in causal effect estimation using targeted maximum likelihood estimation. He applies these and other methods to topical questions in HIV treatment research within the context of IeDEA-SA.