Covid-19 vaccines may not prevent people from getting severely sick or dying, it was claimed today. Trials of hundreds of thousands of volunteers are investigating whether experimental Covid-19 jabs stop a person from picking up the infection. But Professor Peter Doshi, the associate editor of the British Medical Journal, points out scientists are not waiting to see whether volunteers are protected from severe disease or death if they do catch it — which would only be the case if the vaccine didn't work very well — before they are rolled out. This is a particular concern for the elderly, who are the most at risk of severe Covid-19 outcomes, because the vaccine may not be as effective at protecting them from catching the coronavirus in the first place. Vaccines typically do work as well for those over the age of 60 because they have an aged immune system. Professor Doshi, of the University of Maryland, also revealed that the studies will not prove transmission between people can