By Neena Bhandari
SYDNEY, Jun 13 2003 (IPS)

A new HIV vaccine developed in Australia, if successful after its first-ever clinical trial on humans here and in Thailand, will offer hope to the world’s poor in the global fight against HIV/AIDS, say researchers.

"The development of a HIV vaccine is particularly important in resource-poor settings where resistance is a problem and treatment, even using generic pharmaceuticals, remains out of the reach of most people living with HIV/AIDS," said Lisa Maher, associate professor in the University of New South Wales’ School of Public Health and Community Medicine.

Maher, who has worked with sex workers and injecting drug users in the United States, Australia, Vietnam and Thailand, said: "We have been very fortunate in Australia in keeping HIV prevalence among injecting drug users at less than two percent, compared to say Vietnam, where up to 90 percent of injecting drug users are affected.”

”But this has the potential to change (with the vaccine),” she said.

The Australian vaccine, previously untested in humans, is funded by a 16 million U.S. dollar grant from the U.S.-based National Institute of Health and supported by the Australian government.

"We want it to be a vaccine that will be affordable to all and not only for those people, who can pay", said Professor Peter McDonald, chairman of the programme management committee.

"This is the outcome of decades of investment in research in Australia and it’s quite likely to result in the development of novel ways of stimulating the immune system to respond to infections like HIV," he added.

HIV/AIDS is disproportionately infecting and killing the poor. "Only 4 percent of those who need treatment in low – and middle – income countries receive it, whereas in high-income countries, the widespread use of treatment has dramatically reduced AIDS-related mortality," said Worldwatch in a recently released statement.

"By 2010, the number of children orphaned by AIDS is projected to reach 25 million, of whom 20 million will live in sub-Saharan Africa," added Worldwatch.

Australian volunteers will be the first in the world to receive the new HIV vaccine with researchers using a "double whammy" approach to fight the virus. The "double whammy" is based on the "prime and boost" technology that utilises a DNA vaccine designed to ‘prime’ the immune system to recognise components of HIV.

This is then followed by a fowl pox (a bird virus) vaccine designed to ‘boost’ immune cells that will be important in helping the body fight against HIV.

After testing on mice, rabbits and monkeys, the vaccine was ready to be tested on humans, researchers announced last week.

"Under the ‘prime and boost’ technology, we are not introducing a live version of the weakened pathogen so it doesn’t cause disease," said Associate Professor Stephen Kent from the University of Melbourne.

"Fowl pox is a bird virus that can’t reproduce itself in humans. It is being used only as a ‘carrier’ (vector in medical terms)", stressed Kent, one of the trial’s coordinators.

"The main aim of the trial is to have a vaccine that is safe under all parametres and establish that it can produce a strong effect on the immune system in humans," he said. He added that the older vaccine technology of trying to induce an antibody response had proven unsuccessful.

Earlier this year, hopes of finding a vaccine against HIV were dashed when the U.S.-developed AIDSVAX failed after four years of laboratory tests.

"It is an Australian discovery that a ‘killer immune cell’ response is required to control HIV," stressed Kent.

The trial will be carried out on 24 low-risk volunteers at Sydney’s St Vincent’s Hospital over a period of one year, with a view to further testing on a larger population in Thailand, a country that has been seriously affected by the pandemic. HIV/AIDS is the second leading cause of death among Thais aged 15 to 24.

Two persons have already given their consent to participate in the trial being conducted by the Australian-Thai HIV Vaccine Consortium. This comprises a collaboration of Australian universities, the Commonwealth Scientific and Industrial Research Organisation, the Australian Federation of AIDS Organisations and the Thai Red Cross Society.

The consortium also has a community HIV organisation as a full member and expertise from social workers and researchers working with communities, particularly gay men, who are at high risk in Australia.

In Thailand, the trial will begin in mid-2004 on up to 200 low-risk volunteers.

"While the Sydney trial is on Sub Type B, in Thailand the vaccine will be optimised in Sub Type AE, the most common strain of HIV found in South-east Asian countries", said chief investigator of the trial Dr Tony Kelleher, from the University of New South Wales.

But Dr Kelleher warned the trial was only to test the safety and immune response of the vaccine. "There is no evidence the vaccine will prevent HIV and this is not the purpose of the test," he stressed.

The pre-clinical testing had shown that animals suffered pain and their skin turned red at the injection site, and researchers said this was caused by the body’s immune response.

Volunteers have been made fully aware that they may suffer low-grade fever, headache and aches and pains in the muscles.

"However, because participation in this research involves some personal risk, it is crucial that each person considering participation is given every opportunity to weigh up whether or not it is the right personal decision," said the website on the HIV vaccine trial.

But the head of the Australian Federation of AIDS Organisations, Don Baxter, also said that a vaccine available to the public was at least seven to 10 years away.

"As many as 40 million people across the globe are living with HIV and there are 16,000 new infections per day, and progress in getting a safe HIV vaccine has been distressingly slow," he said.

Baxter said he felt the increase in HIV infections might have been partly the result of optimism about treatment and a vaccine, but meantime "we need to ensure community norms about safe behaviour are not jeopardised”.

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