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AIDS Vaccine Is Partially Successful
ifchairscouldtalk writes "A Phase III 'RV 144' study in Thailand succeeded in reducing HIV infection rate in trial with 31.2% effectiveness. The study was conducted by the Thailand Ministry of Public Health and used strains of HIV common in Thailand. It is not clear whether the vaccine, which combines AIDSVAX with Aventis Pasteur ALVAC-HIV canarypox vector, known as 'vCP1521,' would work against other strains in the United States, Africa or elsewhere. Strangely, the vaccine had no effect on levels of HIV in the blood of those who did become infected, providing 'one of the most important and intriguing findings' of the trial, according to Dr Fauci, director of the National Institute of Allergy and Infectious Diseases, which is one of the trial's sponsors."
I'm not normally a stickler for these, but AIDS is a syndrome, HIV is the virus that causes it. The vaccine can prevent you from acquiring HIV and thence from developing AIDS. It's not a cure, it's a preventative measure.
I was promised flying cars...Why are there no flying cars?
Cool! Hopefully by the time I become sexually active it will have improved much more!
You just got troll'd!
...but their conclusions.
How in the hell could you ever do a controlled experiment like this on people if you dont control their exposure to the infection causing material? The only way you can determind improvements of real thing over placebo is if you intentionally expose the test subjects to the virus...which would be a death sentence.
Their results could mean that the group recieving the test vaccine came into contact with the virus 31.2% less.
1331461 is only semiprime *sigh* Alas - I am just short of 1337.
How is that news for nerds ?
None of us will ever get laid, so that's not stuff that matters...
</cliché>
I have discovered a truly marvelous proof of killer sig, which this margin is too narrow to contain.
While this is excellent news, and intriguing scientifically, an effectiveness of 31.8% is practically useless in vaccinating a population. Typically you need at least 70% of your population (varies based on virus) vaccinated before you start to see the effects of herd immunity. Even if they vaccinated everyone in Thailand, you wouldn't get this effect.
Furthermore, the low effectiveness is actually a liability; the end result could be mutations in the HIV virus that make it immune to the vaccine. This is part of the reason why the influenza vaccine has limited effectiveness - influenza, like HIV, has a tendency to mutate quickly. If a new strain comes along, like H1N1 for influenza, you're defenseless.
Finally, I think there's a problem with how the vaccine will be perceived. If the vaccine is only 30% effective, I think people will see that as being too risky to even get the shot. There's already (too much IMO) FUD out there against vaccines in general. If you think that you can get influenza from the flu vaccine, there's a strong aversion to taking the HIV vaccine. For a 30% chance at being immune, that's no good. If it were 100%, that would be a totally different story.
The sample sizes were not 74 and 51. The sample size of people vaccinated was "more than 16,000 volunteers". 74 and 51 were just the number of people infected, which is still statistically significant. [to what confidence level, I do not know].
someone do some analysis on the statistics and tell us all something and get +5
Sure. It's Poisson statistics, so the standard deviation is the square root of the count.
placebo: 74 plus or minus 8.6
vaccine: 51 plus or minus 7.1
The statistical significance of the difference (23) is equal to the standard deviation of the sum (not the difference!) of the counts, so:
difference between placebo and vaccine:
23 (=31%) plus or minus 11
= (2.06 standard deviations)
Assuming they set their criteria for statistical significance at two standard deviations, then they are significant.
http://www.geoffreylandis.com
Fortunately, that gives the the researchers plenty of time...
HA! I just wasted some of your bandwidth with a frivolous sig!
Why is it that on slashdot of all places that should be full of nerds we get idiots that don't grasp basic statistics and people that mod it up? As long as you got a proper control group it's simple to say "If we assume the true probability is the same, how unlikely is it that we get these results?" Of course there's something about the level of confidence - a 99% confidence means there's a 1% your observation is random fluctuations. But the whole "we reject math and logic because the numbers feel to small" sounds like the results of retarded anti-schooling.
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Not at all. What this shows is that the vaccine likely works for some subset of the population. That doesn't mean it doesn't work at all. Viagra for example only works for about 60% of men but people don't go screaming that it doesn't work.
Bottom line here is that vaccine or no, you should still practice safe sex (afterall, HIV isn't the only bad disease lurking around out there). However, if this thing has a ~30% chance of making you immune to the disease with no other ill effects then it's certainly worth reducing your chances by that much.
Basically, to break it down, your chances of getting aids comes down to 3 factors (4 now with this in place):
a * b * c * d
Where
a = the chance that your partner is infected
b = the chance that you catch the disease during an encounter with an infected partner (having intercourse with an infected person doesn't guarantee infection)
c = the chance that your protection fails (only comes into play if you used protection - otherwise it's 100%)
d = the chance that your vaccine was ineffective (only comes into play if you actually got vaccinated - otherwise this is 100%)
Everything that is scientifically proven to reduce the final result, even if it doesn't go to 0% in the end, is a success in my opinion.
"People who think they know everything are very annoying to those of us who do."-Mark Twain
It would be unethical to expose all participants to HIV. They did the next best thing.
There's nothing wrong with the basic idea of the study design. Of course, they may have fucked it up, but that's a different situation.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
But I thought AIDS was sent by God as a scourge of teh gheys. So God must hate the 68.8% it doesn't work for, then.
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I take it you haven't seen this ad.
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Didn't the article say that one group got a vaccine, and the other got a placebo?
"Col. Jerome H. Kim, a physician who is manager of the armyâ(TM)s H.I.V. vaccine program, said half the 16,402 volunteers were given six doses of two vaccines in 2006 and half were given placebos."
Oh yea, that's what it said.
I don't see anything wrong with the basic kind of study. As I said, they may have fucked it up somehow, such as fucking up the selection of the participants and grouping them.
And why would they want to control against additional groups? They're measuring one thing. How effective is the vaccine. Your proposal to control against other groups are actually separate studies. They can and should be run independently at first. I can totally understand them not wanting to add complexity to a study that already has more than 16,000 participants.
So, I still don't see any valid objection as to why this kind of study won't work or is flawed somehow. In fact, this basic type of study is done all the time.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
Apparently you've never watched old movies. Seriously, color is a recent invention.
Belief? Hope? Preference?The Existential Vortex
The total working group for this test was around 16,000 people. Only 125 actually became infected with HIV during those 3 years. The infected portion shows about 1/3 more in the placebo group. So yes, the sample is statistically significant, and someone wasted a mod point.
Who is John Cabal?
The existing battery of drugs is enough to put HIV into remission. Your immune system will remain healthy and the virus particles will essentially disappear. But it's somewhere inside you; if you stop taking those drugs, it eventually comes back although you may have to wait.
HIV has long been known to hide somewhere in the body after drugs have eliminated the actual virus particles. They found where recently; it integrates its sequence into the DNA of T-cells, and the promoter at the start of the viral sequence is capped by a repressor protein. Once it comes off its DNA binding site, viral proteins start getting transcribed again.
They actually developed a drug that can kick it off there and make your AIDS come back again.
This page and this page indicate that the study was double-blind. If it was, then I do not see how your worry is reasonable. If both groups were unaware of whether they received the treatment or not, then I do not see how one group that happened to be the control group would reliably act differently than the experimental group. Am I missing something? Or are you claiming that once people believe they have the vaccine, that they will have more unprotected sex and thus increase their risk of contracting HIV?
Every post I make begins with the assumption P=~P.
Unfortunately, as the article notes, the sample groups may themselves be problematic. A previous study of another vaccine that was found to *increase* infection rates may not have been dangerous; they just neglected to control for circumcision and intravenous drug use. Given this study dates back to before the end of the previous study, their samples may be skewed the opposite direction. Circumcision has been found to reduce the risk of infection by 40-70%. IV drug use is insanely dangerous (I don't know the exact multiplier, but it is rather high). If the test group had a couple hundred extra circumcised individuals, or a dozen or so IV drug users, it could easily skew the results.
Of course, this is still overlooking another problem with the vaccine. It's not one injection, or even one plus a booster or two. It's a two vaccine regimen, with six injections of each component, for twelve total shots (they may eventually be combined, but that all depends on whether the components react with each other outside the body). And the duration of the protective effect is unknown, and likely short (since the vaccine doesn't seem to trigger the production of antibodies). Even if it was incredibly cheap, it's hard to get people to follow up for a second MMR shot, or keep up to date on their tetanus, both of which protect against diseases which are easier to catch without engaging in risky behavior. Can you imagine asking people to pay a few hundred dollars (a guess based on the cost of Gardasil), and visit the doctor half a dozen times to get such a relatively small benefit (reducing risk by about a third, with only two years of testing)?
Even if we assume the samples are good, this is only a first step, and a very short one at that.
In response to the PP: I suspect the confidence level is 95%. Most published studies require that level of precision, and no one likes to hamstring themselves by demanding greater confidence; after all, they spent a lot of money and rejecting the drug would waste it. Of course, if you've ever played D&D, you know how often you get fumbles or critical successes. 95% means the odds of it being insignificant could be as high as the odds of fumbling a roll.
$_ = "wftedskaebjgdpjgidbsmnjgcdwatb"; tr/a-z/oh, turtleneck Phrase Jar!/; print
that's all well and good, but if you don't understand statistics, you probably shouldn't be complaining about the statistics in a study that is undergoing peer review.
I'm not saying you're complaining about the study, I just don't think the excuse you presented holds water.