However, the source cautioned that the results, while extremely promising, did not yet prove that the Oxford vaccine provides long-lasting immunity against the deadly virus.
I can tell you that we now know the Oxford vaccine covers both bases it produces both a T cell and an antibody response. It's the combination of these two that will hopefully keep people safe. So far, so good. It's an important moment. But we still have a long way to go, the source said.
Another source close to the team described the presence of both antibodies and T-cells as a double defence against Covid-19.
The Lancet' medical journal has confirmed that it would be publishing early-stage human trial data from the Oxford team on Monday.
David Carpenter, chairman of the Berkshire Research Ethics Committee, which approved the Oxford trial, said the vaccine team was "absolutely on track".
"Nobody can put final dates... things might go wrong but the reality is that by working with a big pharma company, that vaccine could be fairly widely available around September and that is the sort of target they are working on," he said.
The vaccine development, by the university's Jenner Institute, is being supported by the UK government and AstraZeneca, which will support the production phase.
The pharmaceutical company said last month that phase one trials were due to finish and a phase three trial had begun which will see the vaccine given to thousands of people so it can be tested for efficacy and safety.
vaccine trial team have been working hard on assessing the safety and immunogenicity of ChAdOx1 nCoV-19, and preparing to assess vaccine efficacy, Sarah Gilbert, professor of vaccinology at the university's Jenner Institute who is leading the research, had said back in May.
The vaccine, named ChAdOx1 nCoV-19, is based on a weakened version of the common cold that causes infections in chimpanzees. It also contains the genetic material of the spike protein of SARS-CoV-2 the strain of coronavirus
that causes the Covid-19 illness.
The Oxford University
vaccine is one of more than 100 in development as the novel coronavirus
continues to spread infecting more than 13 million people and killing at least 582,000 worldwide.