The embattled OECD Conference in Genoa announced a $1.2 billion package
to help combat AIDS in the Third World. Vaccine developers and United
Nation agencies are pushing for large-scale clinical trials of AIDS
vaccines in vulnerable Third World populations ravaged by the AIDS
pandemic. AIDS virologists point to evidence that the vaccines are not
only ineffective but dangerous. Dr. Mae-Wan Ho reports.
The culprit viral gene
The intended vaccines all contain gp120, a glycoprotein (protein
decorated with side-chains of carbohydrates) belonging to the envelope
of the human AIDS virus, HIV-1. The candidates include recombinant HIV
proteins and peptides (subunit vaccines), HIV-1 or SIV (the monkey AIDS
virus), killed or 'attenuated', ie, rendered harmless by
successive passage in cultured cells, and a wide range of recombinant
viral, bacterial and plasmid vectors expressing HIV proteins.
HIV researchers Dr. Veljko Veljkovic and his colleagues in Belgrade
Yugoslavia, have shown that the gp120, is similar to the part of human
immunoglobulin (antibody) proteins (Ig) involved in binding foreign
antigens, a crucial step in the immune response. Thus, any AIDS vaccine
containing the gp120 glycoprotein or the gene coding for it could
strongly interfere with the immune system and make the host more
vulnerable to the virus. And in the longer term, it could accelerate
disease progression in HIV patients that do not yet have symptoms.
But the gp120 gene has other properties that pose an even greater
threat to the vaccinated population. It contains 'recombination
hotspots' similar to those in bacteria and viruses such as
Haemophilus influenzae, Mycobacterium tuberculosis, hepatitis B virus
and herpes simplex virus, that often co-infect with the HIV, and also
similar to recombination elements found in immunoglobulin genes and
oncogenes (genes associated with cancer) in the human host.
Recombination hotspots are breakpoints at which genetic exchange or
recombination occurs much more frequently than usual. Recombination of
HIV with bacteria and viruses would generate new pathogens. Within the
human host, recombination with human genes would promote chromosomal
rearrangements and formation of abnormal immunoglobulins, thus
undermining immune responses. HIV-1 sequences integrated into the
genome can act as retrotransposons (jumping genes) that can mutate
genes by jumping into them, and some of the mutations may trigger
Dr. Veljkovic's team, in collaboration with researchers in UK,
Italy and US, already found evidence of recombination between gp120 and
a gene from Haemophilus influenzae . Recombination between an HIV
gene and Mycoplasm fermentans has been implicated in 'Gulf war
syndrome'  affecting a high proportion of soldiers from United
States and the United Kingdoom who served in the Gulf war. A new
subtype of HIV-1 may also have resulted from recombination between HIV-
1 and SIV .
The proponents of the AIDS vaccination trials argue that the desperate
situation precipitated by the AIDS epidemic justifies acceptance of the
'small risks' involved. But Veljkovic and his colleagues
have written a monograph documenting the lack of efficacy of the
vaccines and the enormous risks involved .
Not effective and dangerous
In 1994, the AIDS Research Advisory Committee of the US National
Institutes of Health (NIH) recommended that phase III clinical trials
of gp120 vaccines should not be conducted 'at this time and in
this country'. The reasons, according to Dr. A. Fauci, director
of National Institute of Allergy and Infectious Diseases (NIAID), were
that the vaccines were ineffective; and there was a remote chance that
the vaccines would compromise the immune system and make the recipient
more vulnerable to infection .
The possibility that a vaccinated individual runs a greater risk of
developing an established infection, or of progressing to disease more
rapidly once infected, was confirmed subsequently . The recombinant
gp120 subunit vaccine tested in HIV-negative individuals was
ineffective in protecting them against infection. Those who became
infected during or after vaccination actually had in their blood sera
significant levels of antibodies against the vaccine before they became
infected, but those antibodies failed to protect them from infection.
On the contrary, the vaccine appeared to have acted as a decoy to fool
the immune system into mounting an attack on it, while allowing the HIV
itself to slip through the host defence to get established.
This subunit vaccine is due to go on Phase III clinical trial in Thailand.
Live recombinant viral and bacterial vaccines
The safety concerns for the individual is bad enough. But it is the
effect on vulnerable populations that really worry Veljkovic and his
colleagues, especially from the live recombinant viral and bacterial
vector vaccines (see box).
Live recombinant viral and bacterial vector AIDS vaccines
Many viral and bacterial pathogens are being used as vectors, and a
number are currently considered promising AIDS vaccines. But they are
also promising candidates for generating new infectious agents.
The Salmonella vaccine to be trialed in Uganda
The AIDS vaccine based on live Salmonella vector was developed by the International AIDS Vaccine initiative (IAVI) in partnership with the US-
based Institute of Human Virology (IHV) of the University of Maryland
and the Uganda Ministry of Health. The development of the 'disarmed' Salmonella vector expressing HIV-1 gp120 and gp120-
derived peptides was started in the early 1990s.
The Salmonella vector expressing HIV envelope proteins has been tested
in 37 people in a phase I trial by NIAID. Uganda will be the first
country in Africa to host a clinical trial of this vaccine.
The only safety concern, it seems, was to ensure that the vaccine did
not induce Salmonella disease (ie, diarrhea) in participants .
Whereas, Veljkovic stressed, the right safety question should be: 'Is the probability for transfer of HIV's genetic material
from recombinant Salmonella vector to other pathogens equal to zero?' To which the answer is an emphatic no. Salmonella has the same
kinds of recombination hotspots (called 'Chi') that are
present in gp120, and is known to exchange blocks of genes with E. coli
and other bacteria. The potential is rife for generating new pathogens
by recombination between the Salmonella vaccine and diverse endemic
infectious bacteria in Africa.
The Venzuelan equine encephalitis vaccine trialed in South Africa
An AIDS vaccine based on the live Venezuelan equine encephalitis (VEE)
virus vector, developed jointly by South Africa and the United States,
was due for phase I clinical trials early this year, moving on to large
trials lasting several more years. The country hoped to make a vaccine
against AIDS generally available by 2005. According to a spokesperson
of the Medical Research Council of South Africa, a successful vaccine
has the potential to save 20 million lives during its first decade of use. The VEE vaccine was developed by the University of North Carolina
at Chapel Hill with five-year federal funding from NIAID totally more
than $12 million.
The stated advantages of the VEE vaccine, according to the developers,
are that it targets cells in the lymph nodes, and that 'unlike
vaccinia virus, poliovirus, adenovirus, herpesviruses and influenza
virus-based vaccine vectors, most of the human population have never
been exposed to VEE. Therefore immunisation to HIV with a VEE-based
vector would not be restricted by preexisting immunity to the vector
itself' . Unfortunately, that is not the case.VEE virus is carried by arthropods, and it is endemic in northern South
America, Trinidad, Central America, Mexico and Florida; and eight
different VEE strains have been associated with human disease. These
agents also cause disease in horses, mules, burros and donkeys. Natural
infections are acquired by bites from a wide variety of mosquitoes. The
same virus was also developed as a biological weapon by the US in the
1950s and 1960s.
A herpes simplex viral vaccine shows promise in non-human primates
A modified herpes simplex virus (HSV) that invades host cells and
expresses protein from the SIV has been developed by researchers in
Harvard University into a live attenuated AIDS vaccine, which show promise in non-human primates. They claim that 'HSV vectors show great promise for being able to elicit persistent immune responses and
to provide durable protection against AIDS' . The same
research team has also developed an HSV-2 vector based on another
herpes virus responsible for genital herpes, with the expectation that
this vector could serve a double role as vaccine for HIV as well as
Unfortunately, the HSV genome contains the greatest number of Chi
recombination hotspots of all the microorganisms listed. It also
contains Ig class-switch sequences (also recombination hotspots) and
other sequences involved in the genetic rearrangements that take place
in producing human immunoglobulin genes in blood cells. High levels of
recombination have already been identified in the HSV genome associated
with these hotspots.
A vaccinia virus vaccine led to disease and death
Among the first AIDS vaccine with live viral vectors which was tested
in humans was a recombinant, highly attenuated vaccinia virus
expressing HIV-1 proteins. The vaccinia-gp160 vaccine was developed by
Bristol-Myers-Squibb who performed the preclinical study in the period
1985-1988. The phaseI/II research began in 1988 and was dropped in 1993,
then continued for an additional year. These studies combined the
vaccinia-p160 vaccine with gp160 or gp120 vaccine developed by
MicroGeneSys, Chiron, Genetech, and Immuno AG. Unfortunately, a
recombinant HIV-vaccine virus arose from the attenuated live vaccine,
which was harmful for the immune compromised individuals, producing
symptoms of progressive vaccinia and death . There was also the
danger that the recombinant virus could spread and harm other persons
A canary pox vaccine trialed in Uganda, Haiti, Trinidad and Brazil
Another poxvirus was used, the canarypox virus. When the canarypox
virus carrying HIV genes infect human cells, the cells make proteins
from the genes and package them into HIV-like particles called
pseudovirions that are non-infectious. These trigger the host immune
response against HIV. The first such canarypox viral vaccine carrying
the HIV-1 gp160 gene was developed by Pasteur-Merieux-Connought and, in
combination with Chiron's gp120 construct. It entered phase II
trial in the US in 1997.
The first phase I trial of a canarypox vaccine in Africa was launched
early in 1999. It was tested for safety and immunogenicity in Ugandan
volunteers, and to reveal the extent to which immunized Ugandans have
cytotoxic lymphocytes that are active against the subtypes A and D of
HIV, which are prevalent in Uganda. The vaccine was planned to enter
phase I/II trials in Haiti, Trinidad, and Brazil during 2000.
Is canarypox virus safer than vaccinia virus? Most probably not. Both
are orthopox viruses and are rich in recombination hotspots. This
family of viruses is widely distributed, and recombination between
different poxviruses can readily take place. Recombinants have arisen
that are more virulent than either parent, and it is impossible to
predict the fate of released canarypox vaccine with HIV genes. The use
of these vaccines in Africa where monkeypox is endemic is likely to
generate recombinants with unpredictable pathogenicities. Monkey pox is
transmitted from human to human, but the natural virus is relatively
harmless. Could a recombinant virus arise that may be as virulent as
the smallpox virus?
AIDS vaccines in plants could generate recombinant viruses that switch
hosts from plant to animal
Finally, AIDS vaccines based on HIV antigens produced in plants are
also being developed. The tobacco mosaic virus, TMV, has been used as a
vector to express recombinant coat protein of alfafa mosaic virus (AIMV)
containing antigenic peptides from the rabies virus and HIV-gp120 .
There have already been many examples of recombination between viral
coat proteins in transgenic plants and infecting viruses . In
addition, there is also evidence that a plant virus has switched host
to infect vertebrates and recombined with a vertebrate virus .
Vaccine trials in breach of UNAIDS ethical, scientific and safety
According to the WHO report 2000, more than 90% of all AIDS cases are
in developing countries. UNAIDS and NIH are the two most important
organizations involved in developing AIDS vaccines. UNAIDS Executive
Director Peter Piot has declared, 'It is our collective
responsibility to ensure that all vaccine trials are conducted under
the strictest possible ethical and scientific standards.' But Dr.
Veljkovic has shown that current vaccines based on HIV-1 gp120 can harm
the immune system of individuals and, on account of its recombinogenic
tendencies, has the potential to generate deadly viruses and bacteria
that can spread through the vaccinated populations and to wild life.
The intended vaccine trials are in serious breach of ethical,
scientific and safety standards.
AIDS, more so than other diseases, cannot be addressed simply by
vaccinations, even if efficacious and safe vaccines could be found.
More than drugs and vaccines, we need to end poverty, malnutrition and
environmental destruction, to reinstate social equity and free access
to primary healthcare and education.
A UN body to monitor and control GM experiments
Dr. Veljkovic is calling for the formation of an ' organization
which could pick up information concerning all laboratories performing
GM experiments, like [the] International Atomic Agency which control
all nuclear experiments and activities around the world'. That
should be the task of the International Biosafety Clearing House.
Prljic J, Veljkovic N, Doliana T, Colombatti A, Johnson E, Metlas R.
and Veljkovic V. Identificaion of an active Chi recombinational hot
spot within the HIV-1 envelope gene: consequences for develop-ment of AIDS vaccine. Vaccine 1999: 17: 1462-7.
Nicolson GL, Nicolosn NL and Nasralla Mycoplasmal infections and
fibromyalgia/ chronic fatigue illness (Gulf War Illness) associated
with deployment to operation Desert Storm. Int. J. Med. 1998: 1: 80-92.
Simo F, Mauclere P, Roques P, Muler-Trutwin MC, Saragosti S, Georges-
Courbot MC, Barre-sinoussi F and Brun-Verzinet F. Identification of a
new human immunodeficiency virus type I distinct from group M and group
O. Nature Med. 1998: 4: 1032-7.
Veljkovic V et al Chapter 7. Safety and ethical considerations of AIDS vaccines (courtesy of Dr. Veljkovic).
The HIV vaccine paradox;. Science 1994, 15, 475.
Locher CP, Grant RM, Wrin T. et al. Antibody and cellular immune responses in breakthrough infection subject after HIV type 1 glycoprotein 120 vaccination. AIDS Res Human Retovir 1999, 71, 1685.
Gold D. IAVI launches project to develop oral HIV vaccine. IAVI Report, April-June 2000.
Caley IJ, Betts MR, Irlbeck DM. Et al. Humoral, mucocal, and cellular immunity in response to a human immunodeficiency virus type 1
immunogen expressed by a Venezuelan equine encepphalitis virus vaccine
vector. J. Virol. 1997, 71, 3031
Murphy CG, Lucas WT, Means RE. Et al. Vaccine protection against simian immunodeficiency virus by recombinant strains of herpes simplex virus. J. Virol. 2000, 74, 7745.
Picard O, Lebas J, Imbert JC. et al. complications of intramuscular/subcutaneous immune therapy in severely immune-compromised individuals. J. Acquir. Immun. Defic. Syndr. 1991, 4, 641.
Yusibov V, Modelska A, Steplwski K. et al. Antigens produced in plants by infection with chimeric plant viruses immunize against rabies virus and HIV-1. Proc. Natl. Acad. Sci. USA, 1997, 94, 5784.
Reviewed in Ho MW, Ryan A, Cummins J. Hazards of transgenic plants with the CaMV 35S promoter. Microbial Ecology in Health and Disease 2000, 12, 6-11.
Gibbs MJ, Weiller GF. Evidence that a plant virus switched host to infect a vertebrate and then recombined with a vertebrate-infected virus. Proc. Nat. Acad. Sci. USA 1999, 96, 8022.