Billie Eilish and Katy Perry are among the star names to have signed a UNICEF open letter which is urging the Group of Seven (G7) countries to donate coronavirus vaccines to the global vaccine equity initiative COVAX.The G7 – whose core members are Canada, France, Germany, Italy, Japan, the UK and the US – are meeting in St Ives, Cornwall from Friday to Sunday (June 11-13) for their latest summit, with the global response to the coronavirus pandemic expected to be top of the agenda.In an open