Dr Rachael Williams is Head of Epidemiology at the MHRA and an epidemiologist with extensive experience in safety, effectiveness, and real-world evidence generation. She leads epidemiology programs supporting the evaluation of vaccine benefit-risk profiles through post-authorisation research and safety surveillance. Her expertise includes observational studies, large healthcare database research, pragmatic study designs, and regulatory evidence generation. Rachael works closely with public health, academic, and regulatory stakeholders to advance methodological standards. Her interests include the use of real-world data and innovative study designs to support evidence-based decision-making throughout the product lifecycle.