Source: Lee Harding's channel, where this was found.
Professor Sir Professor Sir John Bell, professor of medicine at Oxford University, and a part of the GAVI team - Sir John is a member of SAGE (Scientific Advisory Group for Emergencies) and sits on the government's vaccine task force that has negotiated the purchase of a handful of proposed vaccines to combat coronavirus - developing AstraZeneca's coronavirus vaccine, said in an interview with Jon Snow that "These vaccines are unlikely to completely sterilize a population. They are very likely to have an effect which works in a %, say 60 or 70%."