The vaccine roll-out of 2021 was a great success, representing an extraordinary marriage of bureaucratic coordination and scientific expertise. To date, almost half the world’s population has had two doses of a vaccine designed to prevent severe outcomes from Covid-19. Over eight billion doses have been delivered – I’ve had three of them. The vaccines have done a good job in relieving the Covid burden on our health services, even when cases are running at high levels, allowing those in need of care access to it.