The coronavirus vaccine, jointly developed by AstraZeneca and Oxford University, has induced a strong immune response in older age groups.
The inoculation produced protective antibodies and T-cells in elderly people, Financial Times reported citing sources.
The finding assumes importance as people in older age groups are seen at the highest risk of contracting COVID-19.
The report noted that the outcome of immunogenicity blood tests conducted on a subgroup of older study participants echoed data published in July this year that revealed that the coronavirus vaccine produced "robust immune responses" in healthy adults aged 18-55 years.
The Oxford COVID-19 vaccine is being seen as a frontrunner in the race to find a viable inoculation, with the result of its clinical trials being closely watched around the world.
Meanwhile, AstraZeneca Plc has resumed the experimental vaccine's US trial after getting approval by regulators.
The British-Swedish pharma giant's advanced stage test has been on hold since September 6, after a participant in the company's UK trial fell ill with what was suspected to be a rare spinal inflammatory disorder called transverse myelitis.
AstraZeneca has signed several deals to provide vaccine to the US and other governments around the world as it inches closer to reporting the first results of its late-stage human clinical trials.
The Oxford coronavirus vaccine is currently undergoing trials in India.
Pune-based Serum Institute of India (SII), which has partnered with AstraZeneca to manufacture the potential COVID-19 vaccine in the country, has agreed to produce 1 billion doses of the inoculation presently undergoing phase-III trials (in India).