The race for a Covid-19 vaccine: 5 things you need to know

There are at the moment more than 40 vaccine trials aimed at preventing Covid-19. Even so, the most optimistic projections are that the earliest a vaccine will be ready is by Easter 2021.

It’s a critical race, since every epidemiological model shows that the virus won’t fully subside until there is a mass vaccination programme to halt infections. But making a vaccine is a field of science in which failure is almost guaranteed: more trials will crash and burn than succeed...