No Debbie Downer HIV-1 post today!
The gods of HIV-1 research have a new paper in PLOS Pathogens, and to me, its real good news for those of us looking for an HIV vaccine.
Im probably going to do several posts on this paper (lots of cool findings), but I want to get this one bit of good news out there before some ass ‘science journalist’ mangles it 😛
Haaland et al followed about 2,000 (2,000) discordant couples (one partner was infected with HIV-1, the other was not). At set points in time, they tested the non-infected individual for the prescience of HIV-1 and antibodies to HIV-1, hoping to catch transmission right when it happened so they could characterize what goes on, so we can figure out how to stop it.
Well, they found what they saw before— Of the 20 couples, 18 of the newly infected partners were infected with ‘one’ kind of virus (it could have been 50 viruses if they were all genetically identical– one genotype of virus). Of the other patients, one was infected with two genetically similar, but not identical viruses, and the other was infected with four.
The Good News
HIV-1 transmission is, in some ways, just a numbers game. Lots of viruses, lots of exposure, youre going to get infected eventually. But is the actual transmission event a numbers game? What I mean is, if Virus Variant A is the dominant genotype in a patients quasispecies, is Virus Variant A what gets transmitted?
If so, this is very bad news for those of us looking for a vaccine, because the dominant component of a quasispecies is different in every patient, every day. There is no way we could vaccinate for HIV-1, if this were the case. It would be physically impossible with todays knowledge and technology.
Good news! Because Haaland et al were following discordant couples, they had samples from the donors, as well as the recipients. So they went back to the donor samples and hunted for ‘the’ virus that infected the other partner… What got transmitted only made up ~5% of the donor quasispecies (if they counted donor sequences that were ‘close’, not just identical).
This means that HIV-1 transmission might not just be a probability exercise! There might be genetic determinants of transmission that we can identify and vaccinate against!