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AIDS Vaccine Yields Limited Protective Effect for First Time


Success with an AIDS vaccine is giving researchers some hope:

"An experiment in Thailand involving 16,000 men and women has demonstrated for the first time a small but measurable protective effect of an AIDS vaccine. The vaccine, a complicated mixture of six 'prime' and 'booster' shots, reduced a person's risk of becoming infected by about one-third compared to people getting placebo injections. The results were barely significant on statistical grounds, perplexing for scientific reasons and unanticipated by most researchers. Nevertheless, the first positive results for an AIDS vaccine after two decades of experimentation was being called a milestone."


The NYT reports: "Results of the trial of the vaccine, known as RV 144, were released at 2 a.m. Eastern time Thursday in Thailand by the partners that ran the trial, by far the largest of an AIDS vaccine: the United States Army, the Thai Ministry of Public Health, Dr. Fauci’s institute, and the patent-holders in the two parts of the vaccine, Sanofi-Pasteur and Global Solutions for Infectious Diseases. Col. Jerome H. Kim, a physician who is manager of the army’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. They then got regular tests for the AIDS virus for three years. Of those who got placebos, 74 became infected, while only 51 of those who got the vaccines did. Although the difference was small, Dr. Kim said it was statistically significant and meant the vaccine was 31.2 percent effective. Dr. Fauci said that scientists would seldom consider licensing a vaccine less than 70 or 80 percent effective, but he added, '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.'"

Said Mitchell Warren, executive director of AVAC, the AIDS Vaccine Advocacy Coalition: "This is a hugely exciting and, frankly, unexpected result. It changes our thinking in ways we hadn’t anticipated. We often talk about whether a vaccine is even possible. This is not the vaccine that ends the epidemic and says, ‘O.K., let’s move on to something else.’ But it’s a fabulous new step that takes us in a new direction."

An ITN video report, AFTER THE JUMP...

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  1. How could it be possible that there are people who volunteer to be tested on the vaccine and then ended up contracting the virus?

    Posted by: Dursley | Sep 24, 2009 9:18:39 AM

  2. Because the vaccine is not 100% effective, hence the caution about how these results should be interpreted.

    The subjects that volunteer will still have activities that put them at risk for acquiring HIV. Of note, the males/females that were included were considered average risk for acquiring HIV. I would have to read the full methods/results of the trial.

    Honestly, I think the numbers are nothing to get excited about at this time, even if deemed "statistically significant". New infections occurred in 51 of the 8,197 given vaccine and in 74 of the 8,198 who received placebo/dummy shots. Granted, anything can be better than the results from the failed STEP trial/Merck vaccine which was ineffective and may have even increased susceptibility to acquiring HIV.

    Posted by: Tim | Sep 24, 2009 10:03:07 AM

  3. Don't get excited about those numbers

    10% lab mistakes

    could have 10%-20% CCR5-Delta 32 carriers due to Britts and northern europeans dipping their wicks in the populations gene pool for a very very very long time now

    Were there any genetic tests on the supposed 32% to see how many might be carrying CCR5-delta 32?

    32% is nothing to get excited about and way too many variables to nix even that low number down to 0

    Posted by: jimmyboyo | Sep 24, 2009 10:52:41 AM

  4. No one is claiming this to be an effective solution. But it is a critical step in a direction that many people thought impossible, given the nature of the virus.

    I'm not sure why kind of lab you've ever worked in Jimmyboyo, but 10% lab mistakes would have cost me my degree. And while Northern Europeans may have been "dipping their wicks" in the gene pool, the CCR5-d32 mutation only provides a protective effect when homozygous - very unlikely that this is higher than 0.05% in the population in Thailand (ref similar studies done in Brazilian populations).

    IMHO - 32% is definitely something to get excited about. It's a tremendous leap in the right direction. It's also important to remember that this vaccine combo was developed >10 years ago. Since then - there have been significant strides in understanding the viral mechanisms. We are definitely on the right path.

    Posted by: wastedPhD | Sep 24, 2009 11:10:02 AM

  5. wastedphd

    Ok 3-4% = standard western lab error rate X3 = 10% Bangkock Thailand = not 1st world country

    My hyperbolic 10-20% ok

    10% Placebo affect (won't budge on that one)

    even your saying .5% CCR5-d32

    anywhere from 13.5%- 20.5% minus out from results

    especialy when no nation accepts a med that isn't AT LEAST 70% effective

    Posted by: jimmyboyo | Sep 24, 2009 11:49:39 AM

  6. Re: the CCR5-d32 issue. It shouldn't matter whether or not there are CCR5-d32 mutations in the Thai population or not; it should only matter if the folks with the mutation were disproportionately likely to be put into the vaccine group. Assuming a random assignment to experiment and control groups, CCR5-d32 would come out in the wash.

    Posted by: S | Sep 24, 2009 11:56:33 AM

  7. Jimmyboyo,

    The placebo effect should apply to both groups equally, since both groups had equal belief that they were getting treatment. So if you think that the placebo effect had a 10% boost for the control group, it should have a 10% boost for the vaccine group as well. The whole design of experimental group/control group experiments is made to factor out the placebo effect.

    On CCR5-d32, as I said above, it doesn't matter if it's prevalent in the Thai population; it only matters if somehow the group assignment wasn't random. And WastedPhD said that CCR5-d32 was likely 0.05% or less, not 0.5% or less.

    I don't have much evidence on the lab error issue, but the Thai Ministry of Health is quite competent, at least when it comes to public health. And Bangkok, while poorer than Western European and U.S. cities on average, is still a major world city and certainly has enough infrastructure to do effective studies.

    Finally, let's repeat that no one is saying that this vaccine combo is the answer or should be used on a large scale right now. But it is the first time we've gotten *any* positive results from a vaccine, so it means we may be on to the right path.

    Posted by: S | Sep 24, 2009 12:06:18 PM

  8. No matter what the statistical theory says. 54 and 71 are awfully small numbers. They should repeat the trials a few more times. Perhaps it will go the other way.

    Posted by: simon | Sep 24, 2009 2:51:27 PM

  9. now would be a good time to buy stock in whatever company plans on rolling out the AIDS vaccine final product

    Posted by: Alan Vinart | Sep 24, 2009 8:30:26 PM

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