Dr. Challen is a postdoctoral research fellow in infectious disease at the University of Bristol, UK working in the EPSRC AI for collective intelligence hub, on the theme of pandemic resilience. His previous research includes the epidemiology, transmissibility and severity of SARS-CoV-2 variants for the SPI-M-O subgroup of Sage and on pneumococcal serotypes, in the Bristol Vaccine Centre. He was jointly awarded the Weldon Memorial Prize for his role advising the UK government during the COVID-19 pandemic. He trained as a medical doctor and practiced in the NHS in paediatrics and neonatology. Prior to the pandemic his research focussed on natural language processing of clinical data, clinical decision support and the safety of AI systems in healthcare.