My main research focus is investigating the epidemiological and economic impact of vaccines and other infectious disease control interventions to support evidence-based public health decision making. Much of this work uses transmission dynamic models to capture ecological effects of interventions beyond the individual.

I am particularly interested in the use of modelling to inform the interface between technical questions about projecting the impact that vaccines can have, and normative questions about what health and economic goals we should pursue. Examples of such questions include the distribution of the costs and benefits of vaccines across different countries and people around the world, and the value of long-term outcomes such as reducing antimicrobial resistance or eradicating an infection.

I work closely with decision makers such as the World Health Organization, country governments and national immunisation technical advisory groups such as the UK's Joint Committee on Vaccination and Immunisation. In particular, my work has helped inform immunisation policy on a range of vaccines (including COVID-19, measles, HPV, pneumococcal, rotavirus, influenza and dengue vaccines) in both developed and developing countries, in close collaboration with partners based in those countries.

A major focus of my recent work has been understanding the Coronavirus Disease 2019 (COVID-19) pandemic and ways to mitigate it. I am currently co-chair for The Lancet Commission for Strengthening the Use of Epidemiological Modelling of Emerging and Pandemic Infectious Diseases, together with Dr Wanrudee Isaranuwatchai from HITAP, Thailand.