A US-based company is developing an eVTOL aircraft for commercial passenger service and is expected to start operations by 2025 or early 2026
"We are now initiating studies to evaluate how well the vaccine induces immune responses in older adults, and to test whether it can provide protection in the wider population."
However, Pollard told BBC radio it was "not possible to predict" when the potential vaccine might be ready for the wider population.
"It is a very difficult question to know exactly when we will have proof that the vaccine works," he said.
Much depended on having enough people who had been exposed to COVID-19 in the trial's next phase, he added.
The university and pharma giant AstraZeneca have signed a deal which could see up to 30 million of 100 million doses for the UK market available by September.
Oxford's effort involves its multidisciplinary Vaccine Group, set up in 1994 to study new and improved inoculations, and the Jenner Institute, which works on both human and livestock diseases.
It is based on a chimpanzee adenovirus - a common cold virus - which has been genetically changed to stop Covid-19 replicating in humans.
The British government, which has given the endeavour around £85 million ($104 million, 95 million euros) in funding, has called it one of the "frontrunners" in the world's vaccine search.
A US-based company is developing an eVTOL aircraft for commercial passenger service and is expected to start operations by 2025 or early 2026
The project’s aim is to generate funds for Harmony House, an orphanage located in India's Gurgaon
Earlier, the Emergency, Crisis and Disaster Management confirmed the reopening of all roads in the emirate
His case was considered a milestone for #MeToo, in which women accused hundreds in entertainment, media, politics and other fields of sexual misconduct
Well-known communication expert Maha Abouelenein on what it takes to thrive in the age of social media
From cultural events, and culinary delights to outdoor adventures, here's a line-up of thrilling activities to make your weekend exciting
'The rom-com garnered $219 million worldwide after its premiere in December
The guitar will be auctioned on May 29 at the Hard Rock Cafe in New York