For the past 25 years, researchers around the world have been working to develop a vaccine to combat AIDS. Chinese scientists were the first to use a live form of the virus as the carrier, where previous attempts used a dead one.

Professor Shao Yiming is a leading expert on AIDS vaccine study in China. He initiated research on using a live virus as the carrier, or vector, 15 years ago.

Professor Shao said, "In the last 25 years, AIDS vaccine research around the world has not produced an effective vaccine. Scientists are rethinking their initial design. One new direction is moving from using a dead replicating incompetent vector, to a live competent vector. We are the only group now using a live competent vector in a clinical trial. The whole field is moving, and changing direction toward where we already are."

The innovative technology has provided encouraging results in initial clinical trials earlier this year, with a primary focus on safety. The vaccine is expected to enter a second phase of clinical trials next year, to test safety and immunity nature. The third and final phase, three to four years away, will test the overall effectiveness.

He said, "We built this new vaccine for HIV testing. Among 48 people, we didn't observe any severe side effects. It has a very good safety profile, proving our design is solid, and the vaccine itself can also induce both antibody responses and T-cell responses against HIV. We aim to finish the second trial in about two and a half years, and then move to phase three. We plan to conclude the phase 5 years from now."

But Professor Shao says the results of AIDS vaccine research are unpredictable, given the complexity of the virus. Over the past two decades, there have been nearly 200 clinical trials involving 35 candidate vaccines worldwide.

He said, "We have not yet experienced the building of a vaccine against viruses or bacteria that can't induce enough protective immunity during natural infection. So how can we design a vaccine which is a product that doesn't already exist in nature? We have to redesign it. We have to be wiser than God and better than nature."

CCTV reporter Liu Ying said, "After dozens of failed attempts worldwide, scientists say it's still too early to provide a timeframe, or to determine the probability of ultimate success. But Chinese scientists say it's important to continue their research. Any minor progress could mean scientists are one step closer to a safe, effective vaccine, which could mean a better life for millions worldwide. Liu Ying, CCTV, Beijing."