Nigel Field is Professor of Infectious Disease Epidemiology at UCL Institute for Global Health. His work focuses at the interface between epidemiology and molecular biology to answer questions about human health and infectious diseases. He leads interdisciplinary scientific teams addressing three major challenges, (1) using large birth cohort studies (Baby Biome Study and C-GULL) to investigate gut microbiota and nutrition in early life and how these affect later health, including respiratory infections and mental health, (2) understanding STIs and the vaginal microbiota to guide improvements in sexual and reproductive health (using the Natsal studies), and (3) control and prevention of emerging infections in East Africa, working with ecologists, vets, social scientists, vector specialists and communities (COHRIE). He established the MSc in Applied Infectious Disease Epidemiology at UCL, which trains new generations of epidemiologists to combat infectious diseases.