Excuse my lack of knowledge in this area, but is this vaccine purely preventative, or is it possible to administer it to someone already infected.

I know/believe with traditional vaccines that you usually have to do it before infection. (Though could be wrong in this regard as well)

If not, why not?

Howie from the Immunity Project here. Thanks for your question! We're really just focusing on the preventive aspect of this vaccine as we head into our Phase I human clinical trials.

Hi Howie, can you elaborate? You didn't really address the why / why not aspect of the question.

Since the Immunity Project concept relies on training the immune system to mount a successful response against HIV, why would it not present some benefit to an already-infected person whose infection is otherwise controlled with drugs?

You may just be focusing on the preventative aspect, but there are many millions worldwide who are concerned with controlling HIV without depending on expensive antiviral drugs that in many cases are completely unavailable.

I'll try and address this since no one has answered yet.

One of the reasons it would be very hard to justify testing this first as a cure is because AIDS patients are by definition immunodeficient. Their Helper T cells (the CD4s mentioned) are being rapidly co-opted by the virus and subject to destruction. In such an environment it is difficult to mount an immune response because the Helper T cells are so instrumental to enabling the cytotoxic immune responses instigated by this study (the CD8 cells are your cytotoxic "killer" T cells).

Any trial run on humans already suffering from AIDS would be muddied by this effect, where the already compromised immune system cannot mount a robust response even were it able to develop CD8 killer cells specific to the HIV epitope they vaccinate with.

Phase I trials are high risk, and especially for a bootstrapped team like this, have a lot riding on them. An early failure can doom a technology in this industry, so it is important to focus on testing in an environment where you have the best shot at success. Downstream studies can focus on other applications if needed.

There are many millions of people who have HIV but not AIDS. Their immune systems work well, and their viral levels are controlled by medications. These people are on US health insurance and are highly monitored already, and easy to enroll in studies, easily accessed and monitored - as they already conform to an HIV medication regimen and see their doctors regularly.

Why would a company not test a technology that may well benefit both infected and uninfected people on both populations? You would only have more data. It will take much longer to see the results if you are only studying it as a preventative measure because you have to wait (a really long time, I would suspect) to see which of your study ends up getting HIV. Additionally, you'd need to study those that do get HIV (if some do, and some probably would, as even the best vaccines aren't 100% effective) and try to see if you can tell if their infection progresses differently or if it is somehow augmented by the vaccination's boost to the immune system. I mean... your explanation doesn't actually make that much sense to me.

Why not test both populations?

I'd imagine limited funds were the reason. Plus, like I said, your results from a trial on patients with the virus on heavy courses of anti-retrovirals would be muddied. You wouldn't know if the antiviral or the vaccine was what was helping/hurting. Also it's hardly ethical to have a test group stop taking their proven medications for an experimental drug, which is what you would have to do to test this properly.

Sorry for the delay! It is certainly an interesting application and one that I am personally very interested in pursuing at some point. For now we are focusing on the preventative potential of this new vaccine concept.

The definition of a vaccine is that it is preventative vs. a cure which is removing a disease from a previously infected patient.

"A vaccine is a biological preparation that improves immunity to a particular disease."

Yes, but immunity has many definitions, including 'to fight off'.

Since it's essentially teaching the immune system, why does this not work when the patient is already infected.

I thought there may be some difference between this and traditional vaccines as well.

This story discusses other HIV vaccine efforts that are targeted at already infected and stop the dependence on the HIV meds:

http://www.livescience.com/18107-hiv-therapeutic-vaccines-pr...

according to that article there are 34 million people already infected worldwide.