Mark Suzman is the CEO of the Bill and Melinda Gates Foundation.

He sits astride one of the biggest charitable endeavours on the planet, a $50bn endowment that has in the last 18 months thrown itself at the Covid-19 pandemic, funding all manner of research and vaccine trials, and now the COVAX scheme itself.

In this conversation with Nicholas Norbrook, he talks through the thorny nature of global collective action problems, and why the world should fund African vaccines shots to avoid a costly new Covid-19 variant.