Vaccine failure exposes Aussies to AIDS risk

AIDS threat ... Nine Australians do not know they may have been affected. [File photo] (AAP: Yang Zongyou)

• Map: Sydney 2000

Nine Australians are believed to be among thousands of people who are unaware a once-promising vaccine for AIDS has increased their infection risk, after they participated in clinical trials around the world.

The multinational trials involving more than 3,000 HIV-negative volunteers were cancelled in September after a large-scale study found the vaccine was not effective at preventing infection.

Researchers have this morning revealed far worse news - those who received the V520 vaccine are more susceptible to acquiring the AIDS virus.

It is understood nine of the 18 people from Sydney involved in the study were given the HIV vaccine but do not know.

The volunteers were warned to protect themselves from exposure to AIDS but were not told if they were administered the vaccine or the inactive placebo.

The information was kept secret to minimise biases in the study.

Scientists will decide over the next 10 days whether those involved in the trial should be told about whether they were given the vaccine or not.

US pharmaceutical giant Merck, which helped develop V520, says volunteers can opt out of the study now and be told if they were given the HIV vaccine.

All but one of the infections were in male volunteers and the bulk of those infected were homosexual men.