Coronavirus: How do you vaccinate 7.7 billion people?

What happens once a coronavirus vaccine is approved? Kalipso Chalkidou, director of global health policy at the Center for Global Development and Nicole Hassoun, an ethicist at Binghamton University in the US, discuss five challenges we'll need to overcome to vaccinate billions of people around the world.

Hear more from Prof Chalkidou on BBC Health Check and Prof Hassoun on BBC Science in Action.

Video by Jennifer Green