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February 24, 2003

HIV vaccine & race

Article from Wired:

The overall expected rate of infection was not reduced in the high-risk people who volunteered to take the vaccine, VaxGen said late Sunday. However, the expected infection rate for the 314 black volunteers who received the vaccine was reduced by 78 percent -- a finding the researchers said was unexpected. The rate was reduced by 67 percent for all non-white volunteers other than Hispanics.

"This is the first time we have specific numbers to suggest that a vaccine has prevented HIV infection in humans," VaxGen vice president Phillip Berman said in a statement Sunday. "We're not sure yet why certain groups have a better immune response."

The Brisbane, California, company said it planned to continue developing the vaccine and will examine more closely why it worked better in blacks and Asians than it did in whites and Hispanics.

"We don't know why. There's a lot of factors that could be involved," Berman said Monday in a conference call, specifying factors such as geography, age and education. "We need to investigate each one of these possibilities."

Genetic factors may be at play, the company said.

Genetic factors? What sort of genetics, since all reputable scientists know that "race doesn't exist." Of course, the other factors might be be at play and explain the discrepancy (perhaps repeated sexual exposure to multiple strains of the virus?).

Posted by razib at 12:22 PM

When it comes to medicine, I don't think the attitude that "race doesn't exist" still holds down here. The serious scientists that I know accept it as fact that racial differences exist, physiologically, and require accounting for during treatment or study. Maybe having grappled with its demons has made the South more able to address the issue openly?

Posted by: Grady at February 24, 2003 01:54 PM

Is there any more data that would allow evaluation of the statistical significance of the results? The information they give indicates
* an overall population of 5400
- of which 1800 got a placebo
- 314 vaccine recipients were black, implying 157 or so black placebo recipients
- infection rate reduced by 78% in the black vaccine recipients (I'm assuming this is the actual infection rate versus the expected - the article says the 'expected rate' was reduced by 78%, but I'm assuming the writer is being sloppy...)
So the problem is that we don't see how many blacks from each group turned out to be infected. It was a high-risk population, but even so, what sort of numbers are we looking at? If 40 black placebo recipients were infected while only 19 vaccine recipients were, that's hugely significant. But if the numbers are 4 and 2 respectively then it could just be a random artifact. I assume these people know their statistics, but I'd like to see the data...

Posted by: bbartlog at February 24, 2003 02:48 PM

the sample seems way too small to really conclude anything-but i just heard on the radio that they recruited white gay men because it was an easy community to work with. of course, the assumption was that white gay men would react the same way as non-whites....

Posted by: razib at February 24, 2003 06:18 PM

I got another piece of the puzzle (from a chart on the front page of my local paper, of all places) - seems that the infection rate for unvaccinated black men ended up being 8.1%, while for the vaccinated it was 2%. So probably 6 of 300-odd vaccine recipients versus 13 of the 157 placebo recipients got infected. That's actually pretty significant - definitely worth a followup. If you assume that a normal rate of infection would be 6% (which is what the rate for the white study group was) then getting only 6 of 300 infected would be very unlikely, much less than 1% probability that chance alone would account for it. Chance is even smaller if you use the 8% rate for the black placebo group as a baseline. In some ways the results are extremely promising, in that the nations of Africa need a vaccine more than anyone else - but unfortunately there's not as much money to be made with a vaccine that only works for blacks, so further tests on this one may not happen.

Posted by: bbartlog at February 25, 2003 08:23 AM

Lets go to a new level of controvercy folks.
I was familiar with this theory but dismissed it until the recent article on AIDS transmission in Africa prompted me to look into it.
Basically, AIDS may not exist at all, and if it exists, it appears unlikely that it has more than a tiny chance of being transmitted heterosexually. You should check out some of these sites, and search for (Nobelist) Karry Mullis and for Peter Duesberg.


Posted by: michael vassar at February 25, 2003 01:27 PM

Michael -
I skimmed through the links you provided and found a lot of evidence that the CDC and others had exaggerated the risks of contracting AIDS, at least for most Americans. I did not find any support for the notion you mention in passing that AIDS may not exist at all. As far as the exaggeration is concerned, there is no need to invoke weird conspiracies to explain it: there are lots of interest groups (pharmaceutical companies, the CDC itself, AIDS patients who want more funding for research) who stand to benefit if everyone perceives it as a threat. As regard the idea of AIDS not existing at all, I have heard of this theory but not seen any evidence to support it; it seems implausible, given that AIDS was first identified by a cluster of specific symptoms linked to severe immune deficiency (Kaposi's Sarcoma, etc.). It clearly exists as a distinct syndrome - it's not like someone found a virus and decided to pretend it caused a disease.

Posted by: bbartlog at February 25, 2003 03:31 PM

People found a virus that correlates with a disease, but the correlation is not nearly good enough to infer causation.

Posted by: michaelvassar at February 26, 2003 10:22 AM

Michael, the existence of SIV and its relationship to HIV, plus the induction of AIDS in chimpanzees via HIV, all put the lie to those claims you quote. Duesberg has reduced himself to a crank over it, and Mullis was always pretty much there all along.

Let it die.

Posted by: Troy at February 26, 2003 11:58 PM

Yes. I no longer think the HIV/AIDS link is non-existent -- though many so-called AIDS cases probably do not have HIV.

I have just put up a draft evolutionary explanation of the vaccine finding on

Posted by: John Ray at February 27, 2003 05:07 AM

This "AIDS does not exist" stuff is complete nonsense.

Durban Declaration on HIV and AIDS

"The evidence that AIDS is caused by HIV-1 or HIV-2 is clear- cut, exhaustive and unambiguous, meeting the highest standards of science. The data fulfill exactly the same criteria as for other viral diseases, such as polio, measles and smallpox:

"* Patients with acquired immune deficiency syndrome, regardless of where they live, are infected with HIV.

"* If not treated, most people with HIV infection show signs of AIDS within 5-10 years. HIV infection is identified in blood by detecting antibodies, gene sequences or viral isolation. These tests are as reliable as any used for detecting other virus infections.

"* People who receive HIV-contaminated blood or blood products develop AIDS, whereas those who receive untainted or screened blood do not.

"* Most children who develop AIDS are born to HIV-infected mothers. The higher the viral load in the mother, the greater the risk of the child becoming infected.

"* In the laboratory, HIV infects the exact type of white blood cell (CD4 lymphocytes) that becomes depleted in people with AIDS.

"* Drugs that block HIV replication in the test tube also reduce viral load in people and delay progression to AIDS. Where available, treatment has reduced AIDS mortality by more than 80%."

Posted by: Jason Malloy at February 27, 2003 04:12 PM

moving back to the test results:

I read in the Economist that the trial was for HIV type B, which is common in North America, less common in Asia, and almost unknown in Africa. Trials in Thailand are underway, and work against type C, the largest threat in Africa, is further back in the pipeline. So the results, even if the racial difference is significant, are not applicable to Africa, in general.

From the article (which is still Economist Premium):

It pointed to apparent efficacy among “blacks” and “Asians”. But these are groups of questionable biological validity, particularly since most subjects were American, with all the ancestral miscegenation that generally implies. On top of all this, the sample sizes of these retrospectively selected subgroups were not big enough for truly meaningful conclusions to be drawn. In the “black” subgroup, for example, there were only 13 infections: four among those who had received the vaccine and nine among a control group given a placebo.

Posted by: Anthony at March 3, 2003 10:30 AM