Vaccine trial starts

Preliminary human testing of an HIV vaccine will commence in Sydney shortly -“ however, the trial organisers have warned that the development of an effective HIV vaccine is still at least seven to 10 years away.

Twenty-four people in good health and at low risk of HIV infection, aged between 18 and 55, are being sought to participate in the trial, which will assess the safety of the vaccine. If this first stage of the trial is successful, additional clinical trials and a second stage trial (to assess the vaccine’s efficacy) will be undertaken in Thailand as early as next year.

The vaccine has already been tested on animals and found to be safe, but the team behind the initiative is cautious not to inflate hopes about the vaccine’s development.

The executive director of the Australian Federation of AIDS Organisations, Don Baxter, said it was important for the gay community in particular to retain perspective on the vaccine trials.

While the trial is taking place, it is important to ensure that people’s expectations about vaccines are not raised inappropriately and that safe behaviours, such as condom use, are maintained across the community, Baxter said.

Dr Tony Kelleher, the principal investigator for the pre-clinical trial, said that the eligibility requirements for participation in the study had been kept very tight but the trial organisers were not ruling out gay men or gay women.

Although low risk of HIV infection is one of the primary criteria for individuals to participate in the study, Baxter explained that the focus is on behaviours rather than identity. Some gay men are at very low or no risk of HIV infection, and therefore they would be considered for the trial, he said.

The project organisers have already received a number of enquiries from people interested in participating in the vaccine trial, with two people already at the stage of giving what the researchers call informed consent.

The chair of the preclinical trial committee, Associate Professor Stephen Kent, said that as far as we can tell from the pre-clinical testing, the only side-effect we see is redness at the injection site -“ a result he described as being entirely consistent with an immune response.

Researchers said that the vaccine -“ which includes a DNA vaccine designed to prime the immune system, as well as a modified form of the fowl pox virus -“ would not lead to HIV infection, but conceded that there were potential risks for trial participants, both in the short and long term (although one third of trial participants will be given a placebo).

Why would anyone participate in this trial? The only reason is altruism, said Dr Kelleher. A booklet that has been prepared for people considering the trial suggests that some people could be motivated because they know someone affected by HIV or they are concerned about the growing global epidemic.

The trial, to take place at St Vincent’s Hospital, is being conducted by the University of NSW on behalf of the Australian Thai HIV Vaccine Consortium, which includes several Australian universities, AFAO, the CSIRO and the Thai Red Cross Society. The project is funded by a grant from the US National Institute of Health which was awarded in July 2000.

Professor Peter McDonald from the Australian National Council on AIDS, Hepatitis C and Related Diseases said the Australian Thai HIV Vaccine Consortium was in advance of other groups who have been funded to develop HIV vaccines. The knowledge gained from the Sydney/Thai trial would feed into further studies, he said.

Although this phase of the trial will determine solely if the vaccine is safe for humans, it may also give researchers the first indications of the vaccine’s efficacy.

This is the first time these vaccines have been administered to human volunteers, which heightens our need to be particularly vigilant regarding safety issues, said Dr Kelleher. We will also be able to undertake a range of sophisticated laboratory tests to determine if the vaccines stimulate the human immune system to produce anti-HIV responses. These responses will help us in further development of the vaccines.

People interested in volunteering for the trial are urged to phone 8354 1068 or log on to www.hivvaccine.com.au.