African HIV Vaccine for Final Trial

STRONG indications have emerged from the International AIDS Vaccine Initiative (IAVI), that the final phase of an African candidate HIV vaccine trial will be conducted in selected African countries just as Australian scientists are set to begin human trials of a "cutting edge" HIV vaccine early next year.

Preliminary plans from the IAVI on the African vaccine indicate that though the trial was initially scheduled for Uganda, when the final phase kicks off in between 2003 and late 2004, it will later be extended to Kenya and a third country that is likely to be either Rwanda, Ethiopia or Tanzania.

The trial vaccine, code-named DNA-MVA, is the first AIDS vaccine specially designed for the most predominant HIV sub-type in Africa. Sub-types A and D are found in Eastern Africa while southern Africa has mostly sub-type C. Europe and America on the other hand have mostly sub-type B.

Presently, the DNA-MVA vaccine is being tested in Kenya and the United Kingdom. It is one of the eight promising experimental vaccines which the IAVI is supporting. From preliminary results given by the Institute, between 60 and 70 per cent of persons on who the vaccine has been tried, showed early signs of immunity against HIV.

IAVI President Dr. Seth Berkley, is optimistic of success even though large numbers of participants would be required as the only way to know whether the vaccine works or not. He adds that the benefit of Uganda participating in the vaccine trial is that if it is declared effective, it would not have to be tested there again.

Normally a vaccine goes through at least three phases of trial. The DNA-MVA vaccine has entered the second phase in the UK. The first phase has been completed in Kenya and preparation is on for Phase 2. Meanwhile, Uganda is planning for another version of Phase 1 designed to determine the doses of the same vaccine being tested in Kenya and UK.

Although Phase 3 is earmarked for 2004, definitive results are expected about the end of 2006 when the world will know for certain whether the vaccine works or not. The IAVI is working towards ensuring that enough doses of the vaccine are manufactured quickly enough to reach as many people as possible within the shortest possible time.

Plans are also afoot to provide funds to pay for people who may not be able to afford the vaccine.

Meanwhile, a "second-generation" HIV vaccine developed by Victorian scientists in collaboration with researchers in Canberra, is to be tested on 24 HIV-negative volunteers at Sydney's St Vincent's Hospital early next year.

Although the vaccine funded from a $27 million grant from the United States National Institutes of Health, may not be commercially available within seven to 10 years, the main objective of the one-year trial is to ensure its safety and efficacy before being tested on a larger, higher-risk population.

Details show that Instead of wiping the virus out altogether, it aims to stop it spreading within the body - an approach differing from many unsuccessful attempts around the world to develop a vaccine because it targets a different part of the immune system.

David Boyle, the CSIRO scientist at the Australian Animal Health Laboratory in Geelong who helped develop the vaccine, described it as a "prime and boost" approach, consisting of two injections.

The first, a shot of modified HIV DNA, primes the immune system's "killer T-cells" to quickly recognise and attack the virus. The second, a shot of harmless fowlpox virus, further boosts the immune system. It has previously been tested on monkeys and on mice both of whom were involved in the development of the vaccine.

But even if a universal HIV vaccine was discovered today, there are no sufficient facilities or adequate plans to take it to all corners of the world in the shortest possible time. For instance, the measles vaccine has been available for long yet about 500,000 children die of measles in sub-Saharan Africa every year.

Data from the UNAIDS indicate that about 42 million people worldwide are living with HIV with 15,000 new infections occurring every day.

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