December 10, 2002 Posted to the web December 11, 2002
Sola Ogundipe
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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LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"