Why it's so hard to create a HIV vaccine
Christina Scott
Africa's biggest HIV vaccine tests were temporarily - perhaps permanently -
stopped in September after a sister study testing the same experimental
vaccine in American men found no protection against infection.
The Phambili tests were "the largest vaccine trial so far in South
Africa
and in Africa", according to microbiologist Dr Koleka Mlisana of the Centre
for
the AIDS Programme of Research in South Africa (CAPRISA). The vaccine was
based on an adenovirus - the common cold virus - so carried no risk of
transmitting HIV itself.
Dr Glenda Gray, from the Chris Hani Baragwanath Hospital in Johannesburg,
South Africa, and a lead researcher with the Phambili vaccine trials,
confirmed
that 700 volunteers from five sites in South Africa had already begun a
series of three injections spaced over 12 weeks.
''Not one volunteer has been put at risk or harmed in any way,'' she
emphasised.
The South African tests, intended to recruit 3000 people, have been
''paused'' until local researchers have studied the American data, based
on
men who have sex with men.
''This is a good sign in a way,'' Gray told www.SciDev.Net . ''This virus is
elusive. We learn from these setbacks. We learn new ways, new ideas about to
find a vaccine. We change our strategies as we learn more."
Although devastated by the setback, the South African team held out the hope
that the results might offer new clues to the way forward - perhaps
for women, or for heterosexual transmission of the virus.
But Gray also said the stoppage was ''a tragedy which has put us back twenty
years''.
The Bio2Biz biotechnology conference in Cape Town in September heard that
only one HIV vaccine, in Thailand, has progressed to the
final stage, phase III clinical trials.
Jim Sherwood, of the Johannesburg offices of the International AIDS Vaccine
Initiative (IAVI), told the conference that the lack of progress was a "sad
state". But he praised researchers for ''casting a wider net'' by using
second level phase II trials to check vaccine effectiveness earlier.
IAVI's introductory double vaccine trial - which uses naked DNA and a
different type of adenovirus from the Phambili vaccine - was originally due
to begin by the end of September in Kenya, Rwanda, Uganda and Zambia. It,
too, may be delayed while researchers study the US data. All the studies
will feed into a bigger series of experimental vaccines to be tested on
several thousand people in Africa and Latin America planned for next year by
the non-profit Partnership for Aids Vaccine Evaluation (Pave).
As in wartime, the cooperation and information-sharing among former rivals
is striking. ''This is a race among equals. There is no competition. We're
all here with a common purpose,'' explained Dr Mlisana.
As in wartime, there will be victims. Some of the vaccines, known only to
researchers, will be deliberate fakes, or placebos. The volunteers
understand that neither they nor their nurses and doctors will know who gets
what. Only the researchers will know who gets the vaccine, and who gets salt
water.
'Some people will develop HIV in these tests,'' confirmed Sherwood. ''This
is the only way to find out what works. The success of the trials rests on
some people who receive placebos becoming infected.’’
In all vaccine testing, whether it's polio or whooping cough or HIV, the
volunteers know they might be injected with a fake. ‘’Of course we do our
best to make sure that everyone on the trial receives the best counselling
about how to avoid becoming HIV positive,’’ Sherwood explained. ‘’But
there
is no other way to find out what works except by conducting this kind of
study.''
The setback illustrates the difficulties in translating promising drugs in a
laboratory setting into success in the real world.
But the playing fields are not level.
Profit-hungry companies like Comforter's Healing Gift, linked to South
Africa's ruling political party (the African National Congress) through its
lawyer Christine Qunta, sells unidentified ''nutritional supplements''
without even completing basic tests to see if they're poisonous to humans.
But researchers have carefully followed hundreds of pages of rules and
regulations, beginning with intensive lab and animal tests confirming that
the proposed vaccines are safe, non-toxic and show virus-fighting power.
Qunta's co-director, informal healer Freddie Isaacs, claims to diagnose HIV
positive people simply by putting his hand on a person's forehead. But every
vaccine volunteer has to go for HIV counselling and tests to make sure
they're negative before the trials begin.
Isaacs sells his treatments without educating his customers. But vaccine
volunteers can't go near the sharp end of a needle without intensive
education about the need for them to practice safe sex, lessons on how the
virus operates and workshops on the risks involved. Follow-up counselling is
a must.
''It's an expensive job,'' admitted Jim Sherwood, based in Johannesburg at
the regional offices of the International AIDS Vaccine Initiative (IAVI).
''But vaccines are the most cost effective intervention available in
medicine.''
Vitamin entrepreneur Matthias Rath doesn't have to check on the health of
his HIV positive customers, even if his staff put clients' lives at risk by
urging them to reject anti-retroviral drugs. But vaccine researchers are
ethically obliged to provide superb medical care before, during and after
tests.
Pseudoscientists with financial interests in Virodene, the paint stripper
once punted by the government as a short-cut to a cure, enthusiastically
hyped it up after testing it on just seven people.
But South African vaccine scientists - who will not personally benefit from
their work - are roughly half-way through years of testing on thousands of
people. They know that even a weak vaccine could deliver a massive blow to
the spread of the disease.
What’s in the vaccine?
Horse viruses. Canary pox. Strings or circles of DNA codes. Synthetic
peptides, ultra-small scraps of protein made of a smattering of amino acids.
All are potential HIV vaccines.
What's missing: the actual Human Immunodeficiency Virus. Many existing
vaccines for measles, flu, or chickenpox use hollowed-out or deactivated
versions of the enemy to alert the body's immune system warriors.
But scientists are just too frightened of constantly-changing HIV, which
binds with our DNA and literally becomes part of us, to use it in a vaccine.
Of course, there is an alternative.
At the International AIDS Society meeting in Australia this year, it was
clear that researchers have grown hugely frustrated at humanity's frequent
refusal to use the easiest, cheapest way to combat HIV. Practicing safe sex
is still a better option. Even if we get a vaccine within the decade, it
won't provide total protection. Condoms are going to be around for a long,
long time to come. ENDS
More information:
 * Christina Scott, Africa news editor of the Science and Development Network
website www. SciDev.Net carried the world's first story that the HIV vaccine trials had
been discontinued because of lack of evidence that the vaccine was working.
* The Centre for the AIDS Programme of Research in South Africa (CAPRISA) is
based at the Nelson Rolihlahla Mandela School of Medicine at the University
of KwaZulu-Natal in Durban, with branches at the National Institute for
Communicable Diseases in Sandringham in Johannesburg, the Health Sciences
Faculty at Groote Schuur Hospital at the University of Cape Town and the
National Bioinformatics Institute at the University of the Western Cape, as
well as at Columbia University in the USA. It's online at www.caprisa.org
.
* The International AIDS Vaccine Initiative has partnered with the Ugandan
Virus Research Institute in Entebbe to test a HIV vaccine and is looking for
volunteers. Check out http://www.iavi.or.ug/ Details about participating in
HIV vaccine trials in Kenya are online at http://www.kaviuon.org
/. It has a
Southern Africa office in Parktown, Johannesburg. For more information,
check out http://www.iavi.org/
* Bio2Biz is online at www.bio2biz.org
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