LONDON (Reuters) - The coronavirus vaccine developed by AstraZeneca and Oxford University would significantly accelerate the roll-out of vaccines in Britain if it is approved by regulators, the country’s Chief Medical Officer Chris Whitty said. “If AZ comes through, if there aren’t any last-minute hitches, it will speed up very substantially the period before we can actually get to the point ... when those in the highest-risk groups ... can all be vaccinated,” he told reporters.