IAN Frazer's genital herpes vaccine has passed its first big test in human trials, with ­researchers showing the product is safe and appears to ­produce an immune response.

A study of the vaccine in 20 healthy people, each receiving three doses, was completed late last year, with results ­described as "encouraging''.

Professor Frazer, the inventor of the Gardasil vaccine against cervical cancer, was overseas yesterday and could not be contacted.

But Lee Rodne, the CEO of Admedus, which is funding the development of the vaccine, said the volunteers had all been screened to exclude ­previous exposure to herpes simplex virus.

He said the researchers found promising evidence that the vaccine had stimulated the participants' immune systems, while being safe, with no major side effects reported.

It was able to generate a T cell response to the herpes virus," Mr Rodne said. "For the next generation of vaccines to not only be strong enough to prevent viruses, but also to treat them, you need to ­activate T cells.''

The vaccine is designed to prevent transmission of herpes simplex virus in people never previously exposed, as well as to act as a treatment for those already infected.

The worldwide market is estimated at up to $6 billion.

Professor Frazer, a former Australian of the Year, developed the experimental vaccine with his team at Coridon, a biotechnology company he founded in 2000. Admedus, which announced the early results of the trial to the Australian Stock Exchange yesterday, has a 54 per cent share in Coridon.