While there is no guarantee, as with previous vaccines, an HIV vaccine at my own university has been given the green light for testing on humans. UWO AIDS vaccine wins approval | London | News | London Free Press I don't know all the info again about previous vaccines, but if this does indeed succeed, we could see the vaccine on the market in five years. As it says, first they'll be testing on it on 40 HIV+ volunteers, then 600 HIV- volunteers, and finally 6000 HIV-. Now I don't pretend to understand how testing procedures work, or why they're testing more negative over positive people...but yeah. I really do hope there's a possibility...
Well I don't see why they'd test it on HIV+ individuals in the first place. Maybe the large number of HIV- individuals are because they'll take the standard odds that that person will contract HIV naturally, and see if this vaccination reduces the odds at all. If it does they'll try a larger sample? Just a guesss.
They probably are testing the positive people as a control or to see if the vaccine can be used to fight the infection once you're already infected.
These trials generally have 3-4 phases. The first phase is non-human trial. The second trial ensures that the drug is safe for humans. The last trials test to see if the drug is effective. So, in this case they are using live attenuated virus, so they would need to test it on humans to ensure that it doesn't cause HIV infection. The logical choice for investigation subjects would be people who already have an HIV infection.
