The trial is the result of a collaboration between the university's Jenner Institute and the Oxford Vaccine Group clinical teams.
Half of the number will receive the COVID-19 vaccine under trial, while the second half will receive a control vaccine which protects against meningitis but COVID-19.
The trial will analyse whether healthy people can be protected from Covid-19 with the vaccine created by the Oxford Vaccine Group - ChAdOx1 nCoV-19.
Of the more than 100 research projects around the world to find a vaccine v described by the United Nations as the only route back to "normality" - seven are now in clinical trials, according to the London School of Hygiene and Tropical Medicine.
The vaccine is made from the ChAdOx1 virus, a weaker version of the common cold virus adenovirus, that has been genetically changed so it can't grow in humans.
Prof Gilbert beforehand mentioned she was "80% confident" the vaccine would work, however now prefers to not put a determine on it, saying merely she is "very optimistic" about its possibilities.
That may very well be an issue if circumstances fall quickly in the United Kingdom, as a result of there is probably not sufficient information.
They are also told there is a theoretical risk that the virus could induce a serious reaction to coronavirus, which arose in some early Sars animal vaccine studies.
Whether a vaccine can be developed before the end of the year will depend on the speed of the trials and whether it can be produced at scale. (NASDAQ: INO), and Johnson & Johnson (NYSE: JNJ) have been working on developing their own coronavirus vaccines.
"We support the development and expedite authorisation of clinical trials for COVID-19 treatments, whilst maintaining our high regulatory standards to ensure the safety of people involved in the trials."Vaccines are being designed from scratch and progressed at an unprecedented rate.
"Any essential worker who needs a test will get a test - their employers will be able to go on gov.uk to get a test for any of their staff who need one".
How can key workers get tested for coronavirus?
It is also supporting research at Imperial College London, which hopes to start clinical trials in June. "So it's hard to argue for that whilst also arguing that a British vaccine should be for British people regardless of worldwide need".
The Oxford and Imperial teams have received more than £40m of government funding.
"From tomorrow (Friday), any essential workers who need a test will be able to book an appointment on Gov.uk themselves, directly". However, the announcement also came with a warning from Britain's chief scientific adviser, Sir Patrick Vallance, that every vaccine is a "long shot".