Vaccine developer warns virus disappearing thwarts his vaccine development: 'We want COVID to stay' --Coronavirus 'disappearing' so fast Oxford vaccine has 'only 50% chance of working' | 25 May 2020 | Professor Adrian Hill describes the efforts to create a vaccine as a "race against the virus disappearing, and against time". There is only a 50% chance of the Oxford coronavirus vaccine working because cases in the UK are declining so fast, one of the scientists behind it has warned. The University of Oxford's Jenner Institute and the Oxford Vaccine Group began developing a COVID-19 vaccine in January using a virus taken from chimpanzees. But with the number of UK coronavirus cases dropping every day, there may not be enough people to test it on, according to the institute's director Professor Adrian Hill. He told The Sunday Telegraph: "It's a race against the virus disappearing, and against time. We said earlier in the year that there was an 80% chance of developing an effective vaccine by September. "But at the moment, there's a 50% chance that we get no result at all. We're in the bizarre position of wanting COVID to stay, at least for a little while."