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October 25, 2009)
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Published online 21
October 2009 | Nature | doi:10.1038/news.2009.1035
News
Expert scrutiny casts
doubt on 'historic' results.
Declan
Are hopes for an HIV
vaccine as distant as ever?Getty
The sponsors of the
largest ever HIV vaccine trial yesterday hailed a "historic" moment as
they formally announced the trial's results at an international AIDS vaccine
meeting in
But some scientists are
much more sceptical of the findings, arguing that the response of the HIV
research community, long deprived of any good news from vaccine trials, is based
more on hope than on rigorous science.
The US$119-million phase
III trial, sponsored by the health ministry of Thailand and the US Army, started
in
The trial's results were
published on 20 October, to coincide with the meeting, in the New England
Journal of Medicine1.
Researchers have been impatient to see the full data since the team announced on
24 September that the treatment had cut the the risk of HIV infection by nearly
one-third (see Vaccine protects against HIV virus). The results are a
"milestone in HIV vaccine research", says Supachai Rerks-Ngarm, the
paper's first author, and a researcher at the Thai Ministry of Public Health.
"Because the history
of preventive interventions against HIV has been so poor, the HIV research
community has seized upon this," says Peter Smith, a tropical
epidemiologist at the London School of Hygiene and Tropical Medicine, and an
expert on statistics. "But at most it is a glimmer of hope. There is not
much evidence from the data that it protects at all."
Data crunch
The trial was set up to
measure the number of people in each group who became infected with HIV, and the
amount of the virus that was circulating in the blood (the viral load) of those
who became infected during the trial.
At most it is a glimmer
of hope
The teams analysed
infection rates in three ways. One, denoted 'intention-to-treat' (ITT), included
the full cohort of 16,402 people. This analysis found that 56 of those in the
vaccine group became infected, which was 20 people or 26% fewer than in
the control group. That difference was not statistically significant.
Another analysis, called
'per protocol', excluded 3,860 people who failed to strictly adhere to the trial
protocols, such as the calendar of vaccinations. This also showed a difference
of 26%, again not statistically significant.
A third analysis the
only one to be presented on 24 September before publication of the full data
used a 'modified ITT' data crunch, which excluded seven participants who
contracted HIV between the time they enrolled in the trial and their first
vaccination. This lowered the number of people who became infected in the
vaccine group from 56 to 51, and the number in the control group from 76 to 74,
yielding a 31% difference between the groups. This just scraped into statistical
significance, with a p-value of 0.04.
The small numbers of
infected individuals in the trial 132 across both vaccine and control groups
also meant that none of the subgroup analyses was statistically significant.
Caution and scepticism
The ITT analysis is
generally considered as the main yardstick of the outcome of drug clinical
trials, although an mITT analysis is also acceptable if agreed by independent
experts. But for vaccine trials, the per-protocol analysis is the most valid,
says Adel Mahmoud, former president of Merck Vaccines and now a molecular
biologist at
The results of this
trial should be treated with caution and some scepticism.
"The results of this
trial should be treated with caution and some scepticism," says Tim Peto, a
researcher in tropical diseases and clinical medicine at the University of
Oxford, UK. "Taken together with the disappointing results of previous
vaccine studies, it is likely that the results could have been due to chance
alone," he says. "The authors do not seem to acknowledge this
possibility."
"My view is that a
more balanced interpretation of the data is that the results show some evidence
that the vaccine might be effective and that, unlike previous vaccine studies,
this study cannot clearly rule out that the vaccine is ineffective," says
Peto.
Nelson Michael, a
researcher at the Walter Reed Army Institute of Research and director of the US
Military HIV Research Program, which co-organized the trial, argues that
including people who didn't stick to their shots reflects a real-world
vaccination scenario, and that excluding those who were HIV-positive before the
trial began was justified. Although the team admit that any protection from the
vaccine is "modest", Michael says that even the trends that are not
significant are worth exploring, as they might open up new avenues of research.
Blood work
The trial also failed to
detect any difference between the viral load in the two cohorts. Mahmoud
describes this as "very, very disturbing", because an effective
vaccine would be expected to at least reduce the viral load in infected
subjects. Michael, however, suggests that this finding might still prompt new
vaccine leads, and that scientists should see if they can uncover the
immunological origin of any possible vaccine protection.
Dan Barouch, a HIV vaccine
researcher at
"Everyone is saying
let's try to have hope, and this is a hope that the results mean
something," says Mahmoud, "but raising expectations with no
fundamental scientific base is dangerous."
"The field is
desperate for some kind of positive result," agrees one HIV vaccine
researcher, speaking on condition of anonymity. "There is a strong tendency
in the community to want to believe - it's hope versus rational science."
References
Rerks-Ngarm, S. et al. N.
Engl. J. Med. advance online publication doi:10.1056/NEJMoa0908492 (2009).
AFP October 20, 2009
Data from an AIDS vaccine
trial in
Volunteers who received
the vaccine had a 31.2-percent reduction in the risk of infection by the human
immunodeficiency virus (HIV), Thai and US researchers told an international
conference.
It marks the first piece
of solid good news in the quest for a vaccine against AIDS, which has claimed
more than 25 million lives since 1981 and left some 33 million people infected,
a tally rising by around 7,400 new cases per day.
The researchers cautioned
that the vaccine was still far from the mark -- generally considered to be at
least 50-percent protection -- by which it could be distributed to the public.
But, they said, it was an
important morale-booster, proving there were ways to prime the immune defences
against a stealthy foe.
"From a scientific
standpoint, it's definitely a breakthrough. But this is definitely not a
public-health breakthrough," Nelson Michael of the US Military HIV Research
Programme, who co-led the trial, told AFP.
He added, though:
"There was a lot of introspection in the field, up until these results were
initially announced and today in detail, about whether or not you would ever
have a vaccine that worked.
"I think that those
doubts have been dispelled to some degree. The question now is can we actually
make one that can become a public-health tool."
Results from the
three-year, 105-million-dollar trial were presented to the media in
The study was published
simultaneously in the peer-reviewed New England Journal of Medicine as Michael
and his Thai counterpart, Superchai Rerks-Ngarm, made their presentation at the
AIDS Vaccine 2009 conference in
The study recruited 16,395
HIV-negative volunteers, of which 8,197 received the vaccine while the 8,198
others received a harmless lookalike called a placebo.
The vaccine combines two
vaccines, ALVAC and AIDSVAX, that were designed some 15 years ago and in
separate trials were previously found to be safe but of negligible
effectiveness.
The conclusion of
31.2-percent effectiveness derives from the number of people who became
infected: 51 in the vaccinated group, against 74 in the placebo group.
The researchers
acknowledged that the number of infections overall was low, but said the outcome
was still statistically significant.
Protection also appears to
be rather lower for people at higher risk of HIV infection and seemed to wane
after the first year following vaccination, according to the trial data.
"This is a
proof-of-concept vaccine," said Michael's colleague, Jerome Kim.
"This is a vaccine
with a limited or modest effect. It was designed for use in
Seth Berkley, president of
a New York-based advocacy group, the International AIDS Vaccine Initiative (IAVI),
said the vaccine field was now generating "a lot of excitement".
In addition to the Thai
vaccine, scientists were advancing on identifying potent antibodies that could
intercept the AIDS virus as soon as it entered the body, he said.
Two big worries are
prioritising this sudden flurry of knowledge and mustering funds for AIDS
vaccine research, which fell 10 percent last year to 868 million dollars, he
said.
"We can't treat our
way out of this epidemic," he said.
AFP October 21, 2009
Richard Ingham
For more than a
quarter-century, their quest has been littered with setbacks while colleagues
who work on HIV treatment have been showered with success.
Promising avenues have led
to dead ends and long, costly trials of prototypes have ended in failure,
saddling the vaccine field with a reputation for lucklessness.
But two pieces of good
news have suddenly boosted morale.
Even though a vaccine
still lies over the horizon, at least a path has now emerged for getting there,
say experts interviewed at the AIDS Vaccine 2009 conference, ending in
On September 3,
researchers in the
On September 24, US and
Thai researchers unveiled the results of the biggest vaccine trial ever.
Tested among more than
16,000 Thais, shots of ALVAC and AIDSVAX vaccines offered 31.2-percent
protection against the risk of infection by the human immunodeficiency virus
(HIV).
This is far too weak to
make it a vaccine for public use.
And nagging questions
arise: why does the vaccine's effect seem to wane over time? Why does it seem to
be less effective among people who are most at risk from HIV infection? And
could it work in
Even so, the trial is
scientific gold.
It proved at last that the
immune system can be taught to recognise and devise a shield, even partially,
against a notorious shape-shifting foe.
"We now have a proof
of concept. It's the first time we've been able to show that," said Anthony
Fauci, director of the US National Institute of Allergy and Infectious Diseases
(NIAID).
"ALVAC/AIDSVAX is not
in itself the answer. It's a start on the road to a vaccine, whereas, before, we
didn't even know where the road was."
"The Thai tests have
provided a vital pick-me-up," agreed Jean-Francois Delfraissy, director of
Seth Berkley, head of the
International AIDS Vaccine Initiative (IAVI), said the research pipeline, which
previously wheezed out tiny drips, was now becoming a small but steady flow.
"There's a lot of
excitement," he said. "You've got the first data about protection.
You've also got extremely potent antibodies that are showing new targets and
there's a lot more of that coming, that field's exploding right now."
"What is happening
now has sort of revitalised optimism," said Muhammad Bakari of the
Muhimbili University College of Health and Allied Sciences in
"If you borrow the
example from antiretrovirals, people thought it would take many, many years to
get these drugs but the speed was much, much faster than what was thought
initially. So I think we should be optimistic."
Bakari's team reported
very encouraging results from an early trial, gathering 60 Tanzanian policeman,
who were given either a Swedish candidate vaccine called DNA/MVA, or a placebo.
All those who were given
the primer and booster showed a very strong immune response, "as high as
any" in previous vaccine trials, he said.
At this early stage, the
vaccine is tested for safety, not for efficacy, and delivery and dosage may have
to be modified, but the results should warrant arguing for a wider trial, he
said.
French scientist Francoise
Barre-Sinoussi, who co-won the 2008 Nobel Prize for Medicine, cautioned that a
vaccine breakthrough still depended on answering fundamental questions about HIV
and the pathways of infection.
With vaccines, "you
are only looking for a single piece of the jigsaw puzzle. A single piece never
gives you the whole picture. It's all the pieces of the puzzle put together that
give the answer."
AFP October 19, 2009
Richard Ingham
"The financial crisis
is of course affecting, and clearly affecting, the capacity of donors to fund
international programs on AIDS," said Michel Kazatchkine, executive
director of the Global Fund to Fight AIDS, Tuberculosis and Malaria.
Speaking to journalists at
the start of a four-day scientific congress on AIDS vaccines, Kazatchkine said
he was worried about donor retrenchment next year, when a three-year round of
fund-raising comes to an end.
"2010 will be a key
year when it comes to funding global health and funding AIDS prevention,
treatment and AIDS science," he said.
"The risk is... that
we lose the momentum, that we lose the trust and that we lose the hope that we
have generated in an unprecedented movement in global health in the last eight
years."
Peter Piot, former chief
of the UN agency UNAIDS and now head of the Institute for Global Health in
"It's very ironic,
(in) that it comes at a time when we have real results -- four million people on
anti-retroviral therapy in lower and middle income countries (and) achievement
in HIV prevention."
Piot added: "Now is
not the time to decrease efforts, because the bill is then going to get higher
and higher. It's a matter of 'pay now or pay later.' We know that there is
money... The bailout of banks has shown that there is money, there is mega-money
when it is needed."
The
On September 24, Thai and
US researchers reported that a prototype vaccine tested among 16,000 volunteers
reduced the risk of HIV infection by nearly a third.
The data was due to be
scrutinised in
Meanwhile, a Swedish
researcher on Monday reported that a vaccine tested on a small scale in
"We hope that our
vaccine could increase protection to 50 percent," Britta Wahren, a
professor emeritus at
The Swedish vaccine,
called Hivis, was tested on 60 healthy policemen in
Several experts questioned
at the conference on Monday reiterated their view that the apparent protection
offered by the Thai vaccine was too low to be considered an effective shield
against HIV.
They also declined to
comment on the Swedish vaccine until they had seen the results.
"We need to see the
data and discuss it and evaluate it," said Alan Bernstein, executive
director of the Global HIV Vaccine Enterprise.
He added, though,
"We're meeting at an important landmark moment in HIV vaccine research...
today, HIV vaccine research is moving faster than at any time in the last 26
years."
By MARILYNN MARCHIONE,AP
Medical Writer - October 21, 2009
Fresh results from the
world's first successful test of an experimental AIDS vaccine confirm that it is
only marginally effective and suggest that its protection against HIV infection
may wane over time.
Yet the findings are
exciting to scientists, who think that blood samples from the trial may show how
to make a vaccine that does a better job.
The results also hint that
the vaccine may work better in the general population than in those at higher
risk of infection, such as gay men and intravenous drug users. It was the first
time an AIDS vaccine was tested mostly in heterosexuals at average risk, and
doctors have long known that how a person is exposed to HIV affects the odds of
becoming infected.
"This study becomes a
landmark. You can put it on a map and begin to figure out where you go from
here," said Col. Jerome Kim, the U.S. Army doctor who co-led the trial.
Last month, researchers
announced that a two-vaccine combination cut the risk of becoming infected with
HIV by more than 31 percent in a trial of more than 16,000 volunteers in
Full results, published
online Tuesday by the New England Journal of Medicine and presented at a
scientific conference in
That's mostly because so
few participants became infected _ only 125 people, 10 times less than in
previous HIV vaccine trials, said Dr. Anthony Fauci, director the National
Institute of Allergy and Infectious Diseases, the study's main sponsor.
Critics had leaked one of
the analyses last week, saying it showed the original results may have been a
fluke. A California-based AIDS advocacy group criticized study leaders for not
giving a fuller picture when they held their news conference last month.
"The bottom line is
that those results are real," even though they are not good enough to
justify using this vaccine now, said Dr. Alan Bernstein, executive director of
the Global HIV Vaccine Enterprise, an alliance of governments, AIDS scientists,
the World Health Organization and funders such as the Bill & Melinda Gates
Foundation.
"We, for the first
time, have evidence of protection, and the nitty gritty (arguments) to me don't
matter a damn," Bernstein said.
Other scientists who, like
Bernstein, had no role in the trial, agreed.
"It's a consistent
story. There seems to be some effect. And I think it is an important study. It
redirects the field to look at a different kind of vaccine and different kinds
of immune responses" than what have been the focus in the past, said Dr.
Lawrence Corey of the
The Thailand Ministry of
Public Health conducted this trial, which used vaccines made from strains of HIV
common in
The combo was tested in
HIV-negative Thai men and women ages 18 to 30 at average risk of becoming
infected. Half received four doses of ALVAC and two of AIDSVAX over six months;
the rest received dummy shots. All were given condoms and counseling, and were
followed for three years after vaccination ended.
New infections occurred in
51 of the 8,197 given vaccine and in 74 of the 8,198 who received dummy shots.
That worked out to a 31 percent lower risk of infection for the vaccine group.
In a smaller analysis of
just the 12,452 participants who received all six shots exactly on schedule,
there were 86 infections _ 36 in the vaccine group and 50 in those given dummy
shots.
Though not a statistically
significant trend, the vaccine appeared nearly twice as effective among those at
low or moderate risk of becoming infected, versus people who share needles, have
contact with prostitutes or engage in other risky behaviors.
"Perhaps the
requirements for protection against transmission in low-risk heterosexual
persons are considerably different or less stringent," Dr. Raphael Dolin of
Chew on this: Gates
Foundation thinks gum, chocolate and malaria may have something in common
By Donna Gordon
Blankinship, Associated Press Writer
October 21, 2009
SEATTLE (AP) -- What do
chewing gum, chocolate and malaria have to do with each other? Not much, unless
you're a young scientist exploring unusual ways to think about world health.
The Bill & Melinda
Gates Foundation on Tuesday announced new grants of $100,000 each for 76
unconventional approaches to world problems.
One will help a UCLA
doctoral candidate explore the idea of using chewing gum to detect malaria
biomarkers in saliva. Another will give a researcher at
Andrew Fung -- the UCLA
student -- admits his idea for an inexpensive and noninvasive new way to detect
malaria started out as an intellectual exercise designed to showcase his
creativity for a potential postdoctorate employer. He was hoping for a job, not
a research grant. He may get both.
Fung's idea was built on
the need for a malaria test that does not require a blood draw and on research
using saliva for detecting other diseases. On the plus side: Saliva is
relatively easy to collect, the process is painless and the gum test doesn't
require a battery or computer to run.
On the negative side:
Saliva isn't as "clean" as blood and biomarkers aren't as prevalent in
saliva as they are in blood. And since children would be a primary target of
this new test, the researchers may also have some problems getting the gum away
from the kids before they swallow it or hide it away.
The biomedical engineer
chuckles at the issues involved in working with kids and is clearly delighted
the Gates Foundation thought his unconventional idea was worth exploring.
"Very few
organizations are willing to invest into that space," said Fung.
Tuesday's announcement is
the third round of the Gates Foundation's Grand Challenges Exploration program
to support innovative, unconventional global health research.
The five-year health
research grants are designed to encourage scientists to pursue bold ideas that
could lead to breakthroughs, focusing on ways to prevent and treat infectious
diseases, such as HIV, malaria, tuberculosis, pneumonia and diarrheal diseases.
Nearly 3,000 proposals
came in for the third round of grants. Dr. Tachi Yamada, president of the Gates
Foundation's Global Health Program, says the foundation hopes this grant program
will someday produce a breakthrough idea that could save untold numbers of
lives.
This year's 76 grants will
go to researchers from 16 countries trying to answer a wide variety of
questions: Can a brief bout of exercise enhance the efficiency of the
pneumococcal vaccine? Can you diagnose tuberculosis by analyzing breath samples?
Should vaccines be administered under the tongue?
Unconventional science is
what attracted Steven Maranz to the Grand Challenges Exploration program. The
"Because of my
background, I usually see things a bit different from most researchers,"
said the American who grew up in
Maranz's plan to look at
the effect of chocolate on the malaria parasite may sound a little strange but
it's based on conventional science.
Maranz had been studying
medicinal plants from
Since the malaria parasite
has developed, over time, resistance to the drugs used to treat people, Maranz
doesn't want to kill the parasite. He wants to find ways to interrupt its
lifecycle in other ways.
Chocolate is a promising
substance for malaria research because it binds with cholesterol and takes it
out of circulation. Since the malaria parasite feeds on fat in the blood, if you
take away the fat, you starve the parasite, Maranz said.
Maranz wants to kill some
of the parasites but leave enough in the blood to help children develop a
lifetime resistance to malaria. He will be looking at several different
compounds but he thinks chocolate is the best candidate because it is rich in
the right elements and is known to be safe.
His chocolate
"medicine" will be delivered in a liquid form, similar to hot
chocolate, because the cocoa in most chocolate bars has been altered with most
of its helpful elements removed.
The scientist is quick to
point out that although he feels confident of his idea, it's still an unproven
hypothesis.
"This is an
exploration grant. The ideas I've been talking to you about need experimental
support. Nothing is proven at this point," said Maranz, speaking for
himself and all the other scientists receiving Grand Challenges grants.
The Gates Foundation was
created in 2000 by the Microsoft chairman and his wife.
Copyright © 2009 The
Associated Press. All rights reserved. The information contained in the AP News
report may not be published, broadcast, rewritten, or redistributed without the
prior written authority of The Associated Press.
22 Oct 2009
Source: IRIN
The trial team in
A few weeks later,
researchers who had seen full data from the trial told Science magazine that an
analysis based only on participants who had received all six doses of the
vaccine at the right times did not show a statistically significant protective
effect.
It was hoped that the
release of more details from the trial to coincide with the AIDS Vaccine 2009
conference taking place in Paris this week would settle the question of whether
the vaccine results were really as significant as the initial announcement had
suggested or a mere fluke. Instead, full results of the study, published online
yesterday in the New England Journal of Medicine (NEJM) raised more questions
than they answered.
The 31 percent efficacy in
the initial announcement was based on a "modified intention-to-treat"
analysis that included all the 16,402 trial participants, except for seven who
were found to have contracted HIV before receiving any vaccinations.
A second analysis included
those seven, while a third "per-protocol" analysis involving 12,452
participants - the one cited in Science magazine - found that the vaccine was
only 26 percent effective. This was not enough to be statistically significant,
meaning that the difference between the vaccine and the placebo arms of the
trial was so small that it could have been a coincidence.
Different interpretations
Dr Jerome Kim of the US
Military HIV Research Programme, who helped lead the trial, yesterday told
reporters at the vaccine conference in
A statistician quoted in a
New York Times report placed more emphasis on the analysis that included the
seven HIV-positive participants, while another did not believe that any of the
analyses provided sufficient evidence the vaccine worked.
In an editorial
accompanying the article, NEJM editor Raphael Dolin said that "although the
merits of each type of analysis can be debated, all three yielded a possible,
albeit modest, effect of the vaccine in preventing HIV infection."
The study authors also
argued that, taken together, the three different analyses of the results were
"consistent with a modest protective effect of vaccine", but could not
explain why other findings from the trial indicated that the vaccine's efficacy
appeared to decrease over time, or why it was less effective among participants
at high risk of infection.
They were also unsure
whether it was one of the two vaccines that produced a potentially protective
effect, or the combination of the two. Dolin noted that the findings raised
"a number of questions that have important implications for future
directions in vaccine research", and recommended that the duration of the
vaccine's effect be addressed by following up the trial participants, as well as
by future trials.
According to a report by a
South African news service, Health-e, Colonel Nelson Michael of the US Military
HIV Research Programme, another lead investigator of the Thai trial, told a
press conference in
21 Oct 2009
Source: Reuters
By
Tan Ee Lyn
PARIS, Oct 21 (Reuters) -
AIDS researchers want to expand their study of a rare group of HIV-infected
people, whose immune systems naturally and mysteriously prevent the virus
thriving in their bodies, to span the globe.
Studies of these
"elite controllers", which aim to find an AIDS vaccine, have so far
concentrated on
Elite controllers are
healthy, have no signs or symptoms of HIV-related disease and no need for
treatment, sometimes as much as 10 years after their infection. Scientists are
hoping to uncover the secret behind their robust immune systems and use it to
design a vaccine for everyone.
"The hope is if we
know the immune protective mechanism in elite controllers, we can target it for
vaccine design," Yu Xu, assistant professor of medicine at Massachusetts
General Hospital and Harvard Medical School, told Reuters after addressing an
AIDS vaccine conference in Paris.
There are now 2,000 such
controllers or "long term nonprogressers" mostly from the
At the conference,
researchers detailed a trial in
Delegates are hoping to
piece together a clearer picture of how to design a vaccine that would prevent
infection.
DOING IT NATURALLY
An estimated 33 million
people globally have HIV, and there is no cure. Drugs can control the virus and
people like the controllers, who can do it naturally, are unusual.
"There are many in
"Last year we went to
"We have
collaboration with
There are two classes of
controllers, the more common being those with 2,000 copies of the virus or fewer
in their bodies, and the even rarer elite controllers who have fewer than 50
copies.
"(Virus in the) elite
controllers can't be detected at all (with regular equipment). On average, an
HIV-infected person has 30,000 copies," Yu added.
Yu's colleague Mathias
Lichterfeld told a news conference that controllers appear to have superior
dendritic cells, one of the many types of immune cells, which appear to be a
point of access for the AIDS virus.
Lichterfeld said some of
the dendritic cells in the patients have higher activity of certain receptors --
molecular doorways in cells. "This offers potentially the opportunity to
manipulate these two receptors to advance vaccine studies," he added.
Controllers also appear to
have unusually powerful reponses to HIV in their CD8 T-cells, another type of
immune cell.
"How do they maintain
the power to respond so fast and effectively?" Yu asked. (Editing by Maggie
Fox, David Stamp)
19 Oct 2009
Source: Reuters
*
HIV may be spread via mouth wounds
* Researchers say shows
need for more treatment options
* Risk of spread by drug
injection was already known
By Allan Dowd
VANCOUVER, British
Columbia, Oct 19 (Reuters) - Smoking crack cocaine daily adds to the risk of
spreading HIV, a Canadian study published on Monday says, although researchers
acknowledge they are not sure about the exact link.
The researchers, who
studied the relationship between drug use and HIV in Vancouver's impoverished
Downtown Eastside, one of Canada's most drug infested neighborhoods, said the
findings show the need for new efforts, such as opening "safe inhalation
rooms", to help drug addicts.
The nine-year study,
published in the Canadian Medical Association Journal, also found that the
number of addicts smoking crack cocaine on a daily basis in the neighborhood has
increased steadily.
The
Researchers said that when
they began the study in 1996 they did not see evidence that smoking crack
cocaine daily increased the risk of contracting HIV, the human immunodeficiency
virus that causes AIDS.
But signs of risk
association developed midway through the study and evidence increased over time,
along with growth in the number of study participants who admitted to smoking
crack, a solid variant of cocaine that is highly addictive.
Study participants who
reported smoking crack on a daily basis were four times more likely to become
infected with HIV than those who smoked it less often or not at all, according
to the researchers.
The virus may be spread
because addicts with mouth wounds share smoking pipes with HIV-infected users,
but the researchers said they did not know for sure. Engaging in unprotected sex
while on drug binges might also be a cause, they said.
The neighborhood has a
higher rate of HIV infection and AIDs than anywhere else in
The link between the
spread of HIV and injection drug use was already well known, but researcher Evan
Wood of the British Columbia Centre for Excellence in HIV/AIDS acknowledged he
was somewhat surprised that smoking crack also posed a risk.
The findings are evidence
"The current approach
simply isn't working," he said.
Among treatment ideas
suggested by the research is the establishment of facilities at which drug users
could smoke under medically supervised conditions with access to information
that could help them fight their addictions.
An appeals court is
expected to rule shortly on