The fast-track development of vaccines against the coronavirus was an extraordinary feat of scientific progress.Now, as vaccines are being rolled out globally, health experts have a vital message: nobody wins the fight against the pandemic until everyone wins.In other words, vaccines must be shared fairly among all nations, rich and poor.Fortunately, there is an ambitious plan to do just that - it's called Covax.Here, we explain the basics.What is Covax?As the race for vaccinations gathered pace last year, there were fears that richer countries would hoard jabs at the expense of poorer ones.Covax was a response to those fears - which have already been realised to an extent.World's poorest must not be 'trampled' in vaccine raceIt is a global initiative that aims to give all countries equitable access to coronavirus vaccines, regardless of their income.Launched in April 2020, Covax is led by the World Health Organization (WHO) - a United Nations body - and two vaccine advocacy groups.Together, they invest donations in the development, purchase and delivery of vaccines to the more than 180 countries that have signed up to Covax.