The coronavirus vaccine developed by Oxford university and AstraZeneca has proved effective in late-stage trials, giving another boost to hopes that the pandemic can be defeated.

The successful results follow the positive trials of rival treatments this month from Pfizer/BioNTech and Moderna, which have lifted global stock markets and signalled a possible end to lockdowns that have wreaked havoc on the world economy.

Under one dosing regime, the Oxford-AstraZeneca vaccine achieved 90 per cent efficacy, a measure of prevention of infection or severe disease. That required a half dose of the vaccine to be given followed by a full dose at least a month later. When the jab was given as two full doses at least one month apart, efficacy was only 62 per cent. The average efficacy, during trials in the UK and Brazil, was 70 per cent.