LONDON -- A phase 2 trial of a COVID-19 vaccine candidate conducted in China has found that the vaccine is safe and induces an immune response, according to a new study published Monday in medical journal The Lancet.

The results provide data from a wider group of participants than the phase 1 trial, which was published in May. Phase 1 trial involved 108 healthy adults and it demonstrated promising results.

"The phase 2 trial adds further evidence on safety and immunogenicity in a large population than the phase 1 trial. This is an important step in evaluating this early-stage experimental vaccine and phase 3 trials are now underway," said Professor Fengcai Zhu from Jiangsu Provincial Center for Disease Control and Prevention, China.

According to The Lancet, the trial of the Ad5 vectored COVID-19 vaccine candidate was conducted in the central Chinese city of Wuhan with 508 participants taking part. Approximately two thirds of participants were aged 18-44 years, with a quarter aged 45-54 years, and 13 percent aged 55 years or older.

Since elderly individuals face a high risk of serious illness and even death associated with COVID-19 infection, they are an important target population for a COVID-19 vaccine, said Professor Wei Chen from the Beijing Institute of Biotechnology in Beijing, China.

"It is possible that an additional dose may be needed in order to induce a stronger immune response in the elderly population, but further research is underway to evaluate this," Chen said.

To battle against COVID-19, scientists around the world are racing against time to accelerate the development of new treatments and vaccines. China has pledged that its COVID-19 vaccine will be made a global public good when it's available.

Meanwhile, Britain is also seeing progress in the development of another vaccine candidate. A separate study published Monday in The Lancet reveals the results of the phase 1/2 trial of the Oxford coronavirus vaccine ChAdOx1 nCoV-19. It indicates no early safety concerns and produces strong immune response.

According to the Oxford University, the trial involves more than 1,000 healthy adult volunteers. The vaccine provoked a T cell response (white blood cells that can attack cells infected with the SARS-CoV-2 virus) within 14 days of vaccination, and an antibody response within 28 days.

Despite the promising findings, it is still too soon to know if this is enough to offer protection and larger trials are under way, scientists involved in this study said.