Oxford coronavirus vaccine 'has only been tested on 500 over-70s'

High hopes for Oxford University's 'ChAdOx' jab but only 1,000 or so of the 10,000 people recruited to UK arm of Oxford's trial are aged 70 or over. Half of them have been given the vaccine and half have had a placebo. Last night, former immunisation 'tsar' Professor David Salisbury said relatively small numbers might not be enough to generate meaningful result