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Sep 24, 2009 02:10 PM | 14
In an early-morning announcement today, researchers reported that an experimental HIV (human immunodeficiency virus) vaccine effectively reduced the number of people who contracted the virus by nearly a third.
Tested in a U.S.-sponsored trial that involved more than 16,000 volunteers in Thailand, the vaccine was administered in six injected doses starting in 2006 to half of the group, and the other half received a placebo. Seventy-four people in the placebo group had contracted HIV by the end of the trial, whereas only 51 of the vaccinated group tested positive.* The injections consisted of two vaccines that had proven unsuccessful on their own: Sanofi-Aventis SA's ALVAC and VaxGen Inc.'s AIDSVAX.
The results came as a surprise to HIV-vaccine skeptics in the AIDS (acquired immunodeficiency syndrome) research field, whose numbers have increased after years of failed vaccine trials. "It's safe to say that the scientific community is caught off-guard," Mitchell Warren, director of the AIDS Vaccine Advocacy Coalition, told Bloomberg News. Before the announcement, Marie-Paule Kieny, director of the World Health Organization's Initiative for Vaccine Research, told the news service: "I don't think that there is a lot of expectation that the efficacy of this vaccine will be very high." A 2007 clinical trial of a vaccine made by Merck was stopped when researchers found that, in fact, more people who received the active vaccine (49) than the placebo (33) had contracted HIV.
Although the news was welcomed by many, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), noted in a press briefing that the findings should be treated with due temperance. "It's opened up a door for us to ask some very important fundamental science questions as well as some clinical questions," he said at the briefing, The Wall Street Journal reported.
The vaccine was targeted especially toward the virus strain circulating in Thailand, and it may not show the same effectiveness where the virus is different, such as Africa or the U.S. And even the 31.2 percent fewer cases that it resulted in is hardly an ideal preventative strategy. Companies prefer to hedge their bets on vaccines that show at least a 70 percent effectiveness rate, Fauci noted at the briefing. Others worry that news about the vaccine might lead some to be less vigilant about more proven methods of prevention, such as using condoms.
The results, however, still show progress in a difficult field. "If you have a product that's even a little bit protective, you want to look at the blood samples and figure out what particular response was effective and direct research from there," Fauci said at the briefing, The New York Times reported. More studies will be required to see if the vaccine can be made more effective and translated to other strains of the virus.
In the meantime, Fauci said at the briefing, "It's like we were groping down an unlit path, and a door has been opened," the Times reported.
Image courtesy of iStockphoto/_maximus_
*Note (9/24/09): This sentence has been changed since posting to correct an error.
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vaccine,
AIDS,
HIV
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14 Comments
Add CommentGood lord, is this an ethical study?
Reply | Report Abuse | Link to this(1) The correct results surely must be 74 and 51 people, not percent (most other sources say people). That would be an astonishingly high infection rate if 10247/16495 people contracted HIV.
Reply | Report Abuse | Link to this(2) In response to joeldooris, this is usually how vaccine studies work; an assumption is made that each group will experience equal exposure to whatever the vaccine is for, and that if it's effective then the vaccinated group will contract the disease at a lower rate.
I do belive that they only infect blood samples, they should probably explain that better.
Reply | Report Abuse | Link to thisConsidering that the scientists didn't know if the vaccine would be helpful it shouldn't be considered unethical. Heck, the Merck-made vaccine appeared to be harmful. This is the only way to see if the stuff will work.
Reply | Report Abuse | Link to thiswell it is unethical in the sense that we allowed the placebo group to practice sexual behavior that resulted in them acquiring the HIV infection, rather than educate them to practice safe sex. But same holds true for the vaccinated group too. Unfortunately there is no other way to know the efficacy of the vaccine.
Reply | Report Abuse | Link to thisIn response to pratandon, the NY Times reports that "for ethical reasons, all [participants] were offered condoms, taught how to avoid infection and promised lifelong antiretroviral treatment if they contracted AIDS."
Reply | Report Abuse | Link to thisEven without these safeguards, I don't think there would be anything unethical about the study. It's not as though the study deliberately exposed anyone to the virus.
"this study is very very ethical, but let's do it in thailand, and not at home, OK?"
Reply | Report Abuse | Link to thisreminds me of the stories about harmful waste:
"oh it's perfectly safe, but lets dump it in africa, not in our back yard."
It's a positive step forward for the fight against AIDS, which ultimately is the end goal. The vaccine needs to be developed further, and who knows what could come of it. http://www.newsy.com/videos/positive_step_toward_cure_for_hiv_aids
Reply | Report Abuse | Link to thisIt would be better journalism to include the selected alpha error rate (alpha is the rate we are willing to accept of incorrectly concluding that there was an effect when in fact there was not). This is very borderline on significance. Using an exact binomial test and assuming n=8,000 for each group, p=0.048 for these numbers. Another way of saying that is if the vaccine combo had NO effect, we would still see the stated difference 4.48% of the time just due to chance and chance alone.
Reply | Report Abuse | Link to thisSo there are two issues: does the vaccine have ANY effect, and secondly, if it does how strong an effect does it really have?
I hope this is progress towards a vaccine, but with something so borderline and considering the past performance of these vaccines and surprise of other researchers, it is more likely a false signal than it is indicative of a real vaccine.
God Willing They Find A Vaccine and/or Cure for this disease.
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Reply | Report Abuse | Link to thisThere really is no other way to find out how effective a vaccine is without putting it through testing. I've read about a vaccine from the Chronic Disease Fund, but it has not been tested by the FDA and EU. They are currently working on raising funds to put it through testing. It looks very promising and I hope it makes it through. http://bit.ly/gQAi1Z
Reply | Report Abuse | Link to thisWell It could be a positive step forward for the fight against AIDS, but I strongly feel in my own opinion that the study using human beings was unethical. I mean why putting humans in more risk when we are still far from finding cure for AIDs, think about it. (www.axcesshosting.com)
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