Sarah Walker (FMedSci, OBE) is Professor of Medical Statistics and Epidemiology at the Medical Research Council Clinical Trials Unit at University College London (MRC CTU at UCL) (40%) and at the Nuffield Department of Medicine at Oxford University (60% FTE).

At UCL she has responsibility for the statistical design, management and analysis of a portfolio of randomised controlled trials and other interventional and non-interventional studies in the field of infectious diseases, particularly HIV, Hepatitis C, the acutely sick child in Africa and bacterial infections, including as Trial Statistician for 15 randomised trials in high-, middle- and low-income countries over the last 10 years. She has a track record in applying efficient but complex and challenging designs, including factorial and multi-arm multi-stage, and novel Personalised RAndomised Controlled Trial (PRACTical) and Multi-Arm Multi-Stage Response Over Continuous Outcome (MAMS-ROCI) designs, to address multiple questions within each trial.

At Oxford, she has been at the forefront of translating advances in genetic sequencing into microbiology services, and linking this sequence data to electronic health records for large-scale epidemiology, with a particular focus on ‘big data’ from routinely collected electronic health records, as part of the “Modernising Medical Microbiology” consortium. She is Director for the National Institutes of Health Research (NIHR) Health Protection Research Unit on Antimicrobial Resistance and Healthcare Associated Infections at Oxford, and Lead of the NIHR Biomedical Research Centre Modernising Medical Microbiology and Big Infection Diagnostics Theme.

Most recently, she was the Chief Investigator and Academic Lead for the UK’s COVID-19 Infection Survey, a partnership between the University of Oxford and the Office for National Statistics, investigating prevalence and incidence of current and past infection with SARS-CoV-2. The survey was the largest study of COVID-19 infection and immunity across all four nations of the UK, swabbing ~150-180,000 participants every fortnight and taking blood from ~100-150,000 participants every month.