Uni researchers believe they have made a breakthrough.
Human trials are reported to have shown promising results after the Oxford University team discovered the jab could provide "double protection" against the virus.
Blood samples taken from volunteers in phase one trials have shown the vaccine stimulated the body to produce antibodies and T-cells, according to a report in The Daily Telegraph.
T-cells play a central part in the body's immune response.
A source told the newspaper that the combination "will hopefully keep people safe".
The Oxford vaccine is one of more than 100 in development as the coronavirus continues to spread - infecting more than 13 million people and killing at least 582,000.
David Carpenter, chairman of the Berkshire Research Ethics Committee, which approved the Oxford trial, said the vaccine team was "absolutely on track".
He added: "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."
The vaccine development at Oxford is being supported by the UK government and AstraZeneca.
The pharmaceutical company's chief executive 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.
The firm has reached agreements to supply around two billion doses worldwide, despite acknowledging that it is not yet certain the vaccine will work.
The vaccine 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 UK government has also given £41m to the development of another coronavirus vaccine being developed by London's Imperial College.
If the vaccine does work, it will first be given to the most vulnerable, such as the elderly and healthcare workers, he said.
The government will also allow technicians, nurses and pharmacists to give the vaccine, as well as GPs.
Nurses and pharmacists can already give some vaccinations without a doctor's prescription.