Friday, November 9, 2007

An HIV Vaccine Study Raises A Question For Me

This article from the November 8, 2007 San Francisco Chronicle tells of an HIV vaccine study that not only didn't work--it may have increased risk for the study group:
Evidence is building that an experimental AIDS vaccine given to 1,500 volunteers not only failed to protect those who received it, but may have put some of them at higher risk of contracting HIV than those who were given a placebo.

At a Seattle meeting held Wednesday to discuss the latest findings, vaccine experts wrestled with the complex questions raised by the disappointing early results of the study, first disclosed by drugmaker Merck & Co. nearly seven weeks ago.

Enrollment in the study was halted at the time, but researchers are still tracking the HIV status of the participants.

"The data are disappointing and puzzling, but we don't have definitive answers" why the results turned out as they did, said Dr. Lawrence Corey of the Fred Hutchinson Cancer Research Center and leader of the study.

The Merck vaccine was made from a cold virus that was genetically engineered to carry three genes from HIV, the virus that causes AIDS. Scientists say it is absolutely impossible to contract HIV from the vaccine itself. The cold virus was also weakened so that it would not make the patient ill.

Additional numbers released Wednesday revealed a total of 49 new HIV infections among men who were assigned the experimental vaccine; and 33 among those given a placebo. A further breakdown of those numbers found that the risk of infection was doubled among a group of men who carried high levels of antibodies to a common cold virus - similar to the hobbled cold virus used as a component of the vaccine.
Now, there are diseases out there for which a vaccine seems like a darn good idea, especially diseases that are hard to prevent. For example, it is difficult, short of becoming a hermit, to avoid catching the flu, or a cold, or polio. These are all easily communicable diseases.

But AIDS? Take the following precautions, and your chances of catching AIDS now are effectively zero:

1. Do not share needles with others.

2. Do not engage in unprotected sex with someone unless you are sure of their HIV status. (Yes, that means that you may have to find out their name first, and delay sex until your third, fourth, or even fifth meeting.)

3. Change your sexual partners less often than you refinance your house or replace your car.

There are still going to be a small number of people that are going to follow all the rules, and still get infected. But this is a trivial number of people--perhaps a few hundred a year in the whole country at first, dropping down to tens a year as the number of new infections declines. Does it really make sense to devote any substantial resources to finding a vaccine for a disease that you can't easily contract without being beyond stupid? And especially when the vaccine turns out to be more dangerous than a placebo?

I know, I know, I'm going to get a bunch of nasty remarks about how homosexuals don't have the option of following rules 1, 2, and 3, because they can't get married. Sorry, I don't buy that. You don't need a marriage certificate to be monogamous, or at least to be careful in your promiscuity.

Would I be upset if enormous resources were being spent on developing a herpes vaccine? Or an HPV vaccine? Or a syphilis vaccine? Yes, and for the same reason. These aren't diseases that just "happen." They are the result of people engaging in relatively risky behaviors. It would be like spending billions of dollars to develop drugs that prevent smoking from causing cancer.

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