COVID: seeking herd immunity by vaccination

In principle, vaccines work by training our immune system to identify and fight a potential future infection, and the COVID vaccines are no different. One thing we’re all hoping for is that the new vaccines will give us ‘herd immunity’ to the virus - this would mean that, for a given population, so many people are immune to the coronavirus that it would start to die away as it can’t find new hosts to infect. But how does herd immunity work in practice, and are the vaccines we have likely to put us in this fortunate position? Eva Higginbotham spoke with Peter English, a consultant in communicable disease control, to find out...