News (Updated
August 23, 2009)
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By Tammie Smith
Published: August 23, 2009
The Richmond AIDS
Consortium, based at
At the
Billions of dollars have
been spent in the past two decades on HIV research. One result: drugs that have
added years to the life expectancy of people infected with HIV.
But efforts to find a way
to rid the body of the virus permanently or a vaccine to prevent infection in
the first place have fallen way short of expectations.
"What makes it so
hard to develop a vaccine is that HIV has so many tricks to fool the immune
system," said Dr. Daniel Nixon, director of the VCU HIV/AIDS Center.
But Nixon said the
National Institutes of Health, which has funded much of the research on HIV and
AIDS, hasn't given up.
"About a year or so
ago they realized they needed to go back to the drawing board a little bit and
more carefully study things in the pre-clinical testing phase. Go back to bench
science and animal models and have more understanding of how these problems
could be dealt with before moving to the big vaccine trials. So there was a bit
of a readjustment," said Nixon, a physician and molecular virologist.
. . .
HIV, the virus that causes
AIDS, destroys a type of white blood cell critical to fighting off infections.
In the past decade, there
have been failures of two promising HIV vaccines in human clinical trials --
VaxGen's AIDSVax in 2003, studied in a trial that enrolled 5,403 people; and
Merck's STEP HIV trial vaccine study that enrolled 3,000 people.
Those failures are partly
what prompted the shift back to the lab to do more basic research to better
understand the virus.
"HIV is always making
itself different," said Nixon, explaining one of the virus's tricks. HIV
also changes some of its proteins to look like the body's own, and in that way
avoids being attacked.
"It's not just one
strain of the virus. In the body, the virus is so diverse. It's millions of
different strains," said Nixon. "Just because you have HIV doesn't
mean you can't get a more aggressive form or a drug-resistant form."
The lack of a vaccine
makes research on better disease management for HIV that much more important.
Nixon said a trial that
the Richmond AIDS Consortium hopes to start soon will look at whether statin
drugs can help reduce HIV inflammation associated with heart disease and
mortality. Another study is looking at what T-cell count level is best for
starting an HIV-infected person on antiretroviral drugs. That study, which is
enrolling people worldwide, will eventually have 4,000 patients.
Guy Bernard Jean of
It's important to be part
of clinical trials, Jean said. "The virus treats everybody differently. We
have to find a common denominator to find a better treatment."
In the
"We haven't given up
on a cure," Nixon said. "As a matter of fact, we have learned an
amazing amount about the virus."
21 Aug 2009 08:20:30 GMT
NAIROBI,
21 August 2009 (IRIN) - New research showing that the tuberculosis vaccine
Bacille Calmette Guerin (BCG) can be deadly to HIV-positive infants means
Kenya's health ministry will have to redouble its efforts to test pregnant
mothers and their infants for HIV, senior health officials say. The South
African study found that HIV-positive babies who receive the BCG vaccine were
three times more likely to contract TB from the vaccine than previously thought.
The authors recommended delaying vaccination until an infant's HIV status is
known. "The new revelations will be challenging to us in regards to
the treatment of children, especially given that diagnosis of both HIV and TB in
children is not easy and takes a long time to determine," Joseph Sitienei,
the director of the National Leprosy and TB Programme at the Ministry of Health,
told IRIN/PlusNews. An estimated 80 percent of children born in
"The biggest
challenge, however, will be to ensure that our healthcare system is strengthened
to deal with these new findings on the dangers and efficacy of the BCG vaccine
vis-à-vis children born infected with HIV," he said. According to
the National Leprosy and TB Programme, children account for about 11 percent of
new TB infections per year.
Emma Quilligan
Website: http://www.scidev.net
Scientists have created a gel that could
prevent the transmission of HIV by physically stopping the virus in its tracks.
The 'molecular condom' was
designed by scientists at the
Patrick Kiser, assistant
professor of bioengineering at the
The presence of semen
makes the vagina less acidic, and it is expected that this change in pH will
cause the molecules within the gel to interact and turn semisolid. The resulting
mesh would be so small, virus particles would be unable to penetrate.
Unlike existing
microbicides, Kiser's molecular condom appears not to be affected by high
temperatures, making it potentially suitable for use in hot developing
countries.
A paper describing the
HIV-blocking properties of the gel was published in Advanced Functional
Materials last week (10 August).
"We have shown that
the gel prevents the movement of HIV," Kiser told SciDev.Net. He added,
however, that the gel's ability to trap HIV has only been shown in the
laboratory and clinical trials are at least three years away.
Kiser hopes the gel will
eventually work in conjunction with existing technologies. "We would want
to put an antiretroviral agent in the gel, to act as another level of
protection," he says.
Salim Karim, director of
the Centre for the AIDS Programme of Research in South Africa (CAPRISA), says he
likes the idea of a "smart" material that responds to pH.
But he adds that Kiser's
team will need to demonstrate the gel's genuine effectiveness as a barrier to
HIV and ability to withstand the force applied during sex. He adds that Kiser's
team may benefit from seeking advice from others with experience in microbicide
research.
Karim says that if the gel
proves effective against the spread of HIV in humans, it could have a
substantial impact on women's ability to protect themselves against infection.
This would be particularly welcome in those developing countries where women are
unable to discuss preventative measures with their partners.
Kiser aims to develop the
gel into a product that remains active for 20-24 hours after a single
application.