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This Month in HIV: A Podcast of Critical News in HIV
  

This Month in HIV: Top 10 HIV/AIDS Stories of the Past Year

May 2008

This podcast is a part of the series This Month in HIV. To subscribe to this series, click here.

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Back to the Drawing Board for HIV Vaccines

Wow. That's great. OK, on to number seven.

Number seven is a downer, and that has to do not so much with hope, but with defeat. What we're talking about here is an HIV vaccine. It's been pretty clear that condoms are great, but we're not going to be able to use condoms to get rid of this epidemic.

We're not going to have people adopt safe sex practices or do any of these other prevention things people have talked about to stop this epidemic in its tracks, except for a vaccine. There's been a lot of money put in by various private and public organizations to try to develop a vaccine.

One of the most promising vaccines was the Merck vaccine. It uses a virus called adenovirus -- which normally causes a cold -- to try and stimulate the immune system. The vaccine also contains viral proteins from the HIV virus that are dead, but that can be used to stimulate a really nice immune response against the virus such that when the person actually encounters HIV, they would already have really good immunity and could fight it off and prevent HIV infection. Well, that was the idea.

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The reality was that the data from a trial of this vaccine that was done among 3,000 people across the planet showed that the vaccine didn't work.27 Not only did the vaccine not work but, very sadly, people who had a strong immune response to the adenovirus at baseline -- meaning before they got the vaccine -- actually seemed to be more susceptible to HIV. There weren't very many infections during the study, there were about 44, but they were concentrated and more likely in the people who had this adenovirus immunity before they got the vaccine.

The bottom line is:

  1. The vaccine didn't work; it did not protect people compared to people who got placebo vaccine.
  2. In a subset of people with an immune response to the vector -- the thing that's included in the virus vaccine -- there even seemed to be a hint that these people were hyper-susceptible to HIV.

Is this the end of all HIV vaccines? Are there others in development?

This is the end for this vaccine. There are similar vaccines that are going to be tested, and I think what you'll see is wider use of these vaccines in people who do not have immunity, or an immune response, to the adenovirus vector.

I think there's going to need to be much further work. There's a strong and vocal group that feels that vaccines are nowhere near ready for testing in humans and that we really should go back to the drawing board. There are others who feel an urgent need to start clinical vaccine trials in people.

I think this, at the very least, puts a big chill on HIV vaccines in general. Many vaccine trials were either underway and had to be stopped, or were about to start and had to be stopped. We're going to have to try to understand what it is that's going to make the immune system develop a protective response against HIV.

The fact that people can get superinfected with virus (i.e., people can be HIV infected and still acquire a new strain of HIV), bodes very poorly for us being able to figure out how to trick the immune system to have a great response.

If natural infection with virus doesn't protect you, that means we have to do even better than Mother Nature and produce a super response. I think that's going to be extremely daunting and very difficult. Sadly, that's what we learned with this vaccine trial.

One interesting thing about this vaccine trial that came out recently was that, among men who were circumcised, there was much less risk of HIV infection -- such that it partially neutralized the increased risk that occurred by having that adenovirus immunity at baseline.28 I think that's really interesting, and again, shows that there is a role for circumcision in HIV prevention. It's not going to be the cure-all, it's not going to be the magic bullet, but it certainly can be very powerful.

Crystal Meth and HIV

On to number eight.

Number eight, basically, is just trying to understand where methamphetamine [meth] use fits into the HIV epidemic. We're learning and understanding that the number of people with HIV infection in our country is increasing, it's not decreasing,29,30 and that transmission of the virus among men who have sex with men also seems to be increasing. I'm interested, and I think others are also, in understanding how much meth use contributes to this.

What I wanted to highlight here was not a news story; there are people who work in big cities that have seen meth for years now. I think what we're understanding is that there's just not as much information as we need. There certainly isn't a good understanding of what the contribution of meth is to some of the statistics we're getting from the CDC and elsewhere. I think that's one thing.

The second thing is just how much meth use impacts what happens to people with HIV infection. I think meth use is probably going to be found, conclusively, to be associated with poorer outcomes. We're seeing some evidence that it could be associated with HIV drug resistance, and acquiring HIV drug resistant virus.31

We're seeing also that treatment for methamphetamine is dismal, and that the prognosis of people who are meth users is not very good.32 We see this in people; in their testimonials, they indicated that getting off this particular drug is extremely difficult.

I think that there is a story here. I think it's one that's going to persist. I think that all we need to do is not lose track of how methamphetamine is probably responsible for more than we realize when it comes to the expanding HIV epidemic here in our country.33 It's not only on the West Coast; it's not only on the East Coast; it's in the interior. I work in North Carolina, and we're seeing this in rural dwellers; we're seeing this in the Midwest. I think this is a big story, and we're only seeing the tip of the iceberg, here.

It's about the present as well as the future, then?

It totally is. The best prediction of the future can be examining the past, and we've seen what happened with crack cocaine. I think we're starting to see the signal from methamphetamine. Methamphetamine use in one of the studies that I cite from San Francisco has increased dramatically among homeless and near-homeless people -- from 5 to 15 percent.34 We're seeing the use among men who have sex with men increase dramatically.

The characteristics of this drug are like nothing we've ever seen before. People become hypersexual; people become wide awake and have sex for hours and days at a time. People are not using meth and then putting on a condom.35 It causes impotence so that some men who are normally on top become bottoms, leaving them more susceptible to HIV infection.

It's just incredibly devious and evil, and it's the kind of thing we don't need right now. I think it's erasing some of the benefits and some of the advances we had in trying to control this infection and the spread of this infection. I think this is a huge concern. Maybe I'm being Chicken Little and saying the sky is falling, but from all the data I'm seeing, I think that methamphetamine use is one of the biggest threats we're going to face in this country when it comes to containing HIV infection.

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Copyright © 2008 Body Health Resources Corporation. All rights reserved. Podcast disclaimer.

This podcast is a part of the series This Month in HIV. To subscribe to this series, click here.


  

This article was provided by TheBody.com. It is a part of the publication This Month in HIV.
 

 

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