I have developed several analytical models to assess the potential costs and consequences of various vaccines, including those for rotavirus, human papillomavirus, and respiratory syncytial virus. The models provide a framework for stakeholder engagement, capacity strengthening, and national ownership of results, and have been used to support national vaccine committee decision-making in over 40 low- and middle-income countries (LMICs). My research has informed global WHO guidelines (e.g. the policy to relax rotavirus vaccine age restrictions in high mortality settings - Clark et al, Lancet Global Health 2019) and provided insights into: the timeliness of children's vaccines in LMICs (Clark et al, Lancet Global Health 2026; Clark and Sanderson, Lancet 2009), the number of people at increased risk of severe COVID-19 disease due to chronic conditions (Clark et al, Lancet Global Health 2020); the efficacy and duration of protection of live oral rotavirus vaccines (Clark et al, Lancet Infectious Diseases 2019). I am particularly interested in analytical models that are able to capture heterogeneity in disease risk, and heterogeneity in vaccination coverage, within and across populations. Students with an interest in this topic are welcome to contact me.