This post is funded by WHO and involves developing mathematical models of COVID-19 vaccination. The main goal is to assess the impacts of current and variant-adapted vaccines on the transmission dynamics of COVID-19 Variants of Concern. This will involve recoding and extending an existing model of COVID-19 vaccination developed by the Warwick-Lancaster Team and using it to address a set of policy questions provided by WHO. This position is available for seven months while the rapid-response call is ongoing (starting in January 2023), but other opportunities may be available in the wider group beyond this period.