March 9, 2001

11:11 AM

Vaccine Prevents AIDS in Monkeysand could lead to human medicine. Exciting huh? Anyway, if that should happen, how much do you think they'll charge for treatment, considering the conspiracy theories and all that?
posted by tiaka (11 comments total)

AIDS typically takes up to ten years to develop after initial infection of humans with HIV. How the heck can they know they've prevented AIDS after only 24 weeks? Perhaps all they've done is slow the onset.
posted by Steven Den Beste at 11:54 AM on March 9, 2001

from the article: keep in mind they're talking about monkeys; not humans - the time span is different.

Three of the four unvaccinated monkeys developed AIDS within 23 weeks.

Within 2 weeks of infection, levels of the virus were at least 10 times lower than in the unvaccinated animals, and they soon dropped to undetectable levels

posted by bliss322 at 12:12 PM on March 9, 2001

Let's just assume for a second that this works...

This will actually increase the spread of HIV, since 1) it decreses the mortality rate of HIV increasing the infected population and 2) a vaccine will make HIV infection less "scary" because it can be controlled.

Overall that doesn't seem bad. Sure, HIV spreads, but no one dies. No big deal.

EXCEPT for the fact that with an exponentially larger population of HIV viruses, natural selection will take it's course and eventually make a virus strain which is resistent to the vaccine. The reason Ebola (hantaviruses etc) hasn't killed off everyone on the planet is that it kills off the host to quickly to spread. HIV, although a much less virulent virus, has a longer incubation life and hence spreads more widely. This vaccine would exacerbate that effect.

Don't misunderstand me: Saving lives is a great thing. I'm just thinking that, from a scientific point of view, this could set up a pandemic super virus which potentially could be much more lethal and widespread than normal HIV.
posted by fooljay at 12:17 PM on March 9, 2001

tiaka, I made a couple phone calls to several of the bigger drug companies, and the consensus seems to be that conspiracy theories are a "generally moderate" factor in determining the price of AIDS medication. Merck's spokesperson stated that "obliterating the Negroid race" was only one of many goals in establishing spot-market pricing, but definitely not a primary concern.
posted by techgnollogic at 12:40 PM on March 9, 2001

Well.. more power to 'em and.... -Hey! Wait a minute.
posted by tiaka at 12:51 PM on March 9, 2001

I don't know about this stuff but I guess it means that safe sex is doing it with monkeys. I heard that they make lousy pets though.
posted by Postroad at 1:40 PM on March 9, 2001

Fooljay, the article states that the viral levels dropped to undetectable in the vaccinated monkeys - which makes them effectively "HIV negative." It also states that it's harder to transmit the virus when it's at lower levels. If this vaccine merely prevented illness while still allowing the virus to live, then I'd agree with you that wouldn't be a full solution. But it does sound as if it could in fact lower transmission rates and new infections, if in fact the virus basically doesn't survive in a vaccinated person.
posted by dnash at 1:52 PM on March 9, 2001

Thanks dnash. I must have missed it. I see it now.
posted by fooljay at 2:21 PM on March 9, 2001

Well, the title is misleading anyway. Monkeys get SIDS, not AIDS. It sounds like the virus they were innoculating against was a hybrid SIV virus that expresses the HIV proteins they were targeting with the vaccine.

fooljay, I think you're confusing the vaccine, which would essentially prevent initial infection, with some of the treatments currently in use, which treat infection after the fact.
posted by shylock at 2:26 PM on March 9, 2001

Given that HIV is a retrovirus, if it's managed to transcribe its genes into T cells then it doesn't matter whether the level of virus in the blood drops to zero because the genetic information is there for T cells to create the virus again later. In humans, the level of HIV drops way off after the initial infection, nearly to zero in fact. That's because, in fact, the person's immune system does successfully mount a defense against the virus. But then, over the course of years, it rises again as the immune system declines.

I've always thought that the fascination with a vaccine for HIV was simply because vaccines are the only weapon we've ever had against viruses. But in the case of HIV, it's not clear that any blood level at all for any length of time is safe, because during the time it's present it has the opportunity to infect T cells and to transcribe its genetic material into their chromosomes. Then as the T cells divide (as they do) the number of infected ones will rise even without any new virus.

A vaccine doesn't prevent infection. What it does is to pre-prime the immune system so that the response to infection is faster and more effective. But every other virus known is only dangerous when quantities reach excessive levels. We've never dealt before with a virus which appears to be deadly (in the long run) at any concentration. As such, it's never been obvious to me that it was theoretically possible for even an effective vaccine to help in the case of HIV.

Has anyone yet actually worked out the mechanism by which the immune system declines during progression to AIDS?
posted by Steven Den Beste at 3:32 PM on March 9, 2001

Well, it's kind of complicated. There are people who really do seem to have developed some sort of immunity. There are (1) people get infected but never seem to lose their T cells, (2) people whose T cell counts drop, but who never develop full-blown AIDS, and (more recently discovered) (3) people who never actually seem to get infected despite repeated exposure to the virus. It's just not clear yet what's different about the immune responses these people exhibit that protects against AIDS.

more science funding more science funding more science funding
posted by shylock at 7:31 PM on March 10, 2001