hereHe added: “I think it’s very difficult to answer the question because first of all we have to do the analysis to find out whether they work.”Prof Pollard said that a vaccine that is at least 50 per cent effective could “halve the number of deaths or hospitalisations here in the UK” which would be “a dramatic change from where we are today”.But he added that testing vaccines for a 50 per cent efficacy is harder and may take longer to demonstrate.Prof Pollard added: “I think we are all hoping