We have a vaccine against just about every other virus under the sun. So why haven’t we developed an AIDS vaccine yet? I’m not trying to set off a great debate, I am just curious.
Actually, there are a great many viruses for which there is no vaccine. (Have you had your cold shot, lately?)
The HIV, like the various pathogens that cause the “common” cold is prone to reconfiguring itself in ways that make it hard to come up with a vaccine that will actually trigger the proper immune response in the body. Additionally, of course, is that the target of HIV is the immune system, so any vaccine that prompted a reaction could have the unintended consequence of suppressing immunity, just as HIV does, now.
Contrast this to the various influenza pathogens. They also mutate at a fairly rapid rate. Each year, scientists have to guess which recently recognized flu bug will be the one to cause the most infection, after which they attempt to produce the vaccine for it. If the specific strain of influenza does not happen to become very virulent that year, they are castigated for making people sick with a “worthless” vaccine. If they choose the wrong bug to fight, they are castigated for not preparing the correct vaccine. With AIDS, (as with the rhinoviruses that cause colds), they are not even sure that they have a handle on how to create the vaccine, yet.
In addition to being a rhinovirus (for which vaccines are very rare), HIV attacks the “T-helper” cells of the blood - these are the “traffic cops” which direct the immune system - so any easy solution is impossible, because the easy ones boost the immune system - HIV blinds the immune system, so any antibodies present cannot be directed to the infection.
But HIV is not a rhinovirus.
No, but it is a retrovirus.
So, what’s a rhinovirus and what’s a retrovirus and how does HIV being one or the other affect our ability to come up with an effective vaccination?
I really like tomndeb’s analogy. HIV is a squirley bugger. Unlike the influenza virus (and many others), though HIV’s secret is shoddy construction. Basically, everytime it replicates a new virion it makes a mistake (I think it’s one mistake on average) in the viral genome copied. So the progeny all have mutations. Many are non-functional or poorly functional, but some are better and get selected by the immune system (by killing off the others).
Two interesting points- 1) The drugs to treat HIV infection are complicated to take and can cause pretty icky side effects, but when there is 100% compliance (a rate that I’ve only heard of in a prison trial where each patient/inmate was watched as they took each pill) there is no development of resistance. The problem is that despite the best motivation, no one can keep up perfect compliance and the lower drug levels end up acting as selecting agents.
Intersting point 2) the mutations that make the virus resistent to drugs usually make them less effective at the job of being a virus (cell entry/replication/release), but also less affected by the drug- so without the drug, the mutants that are resistant are selected against and die off.
Sorry to get off the topic, but I hope that helps.
PC
A retrovirus is one that uses RNA to encode its genetic material rather than DNA. Usually, RNA is a messenger agent. By using the enzyme reverse transcriptase, a retrovirus stores its genetic blueprint in RNA which, when it invades the host cell, uses its “messenger” aspect of RNA to tell that invaded cell to begin manufacturing more of the retrovirus–thus using the host’s defenses against itself. (Way too simplistic, but I hope that suffices.)
A rhinovirus is simply one that lives and breeds in the nose (as many cold viruses do). I suspect that my use of rhinovirus simply affected happyheathen’s typing and that he meant retrovirus in his post.
this is the simple explanation that my friend told me (he’s a Dr. of Pharmacology)
The reason why we don’t have an AIDS vaccine is because once you contract AIDS, it literally changes your DNA…(waaaaay over simplifying here)…basically we don’t have anything that can operate on that level with the technology we have…
(not yet anyway)
I took one of my moggies to the vet today, and was informed that in the US there are trails being conducted into a vaccine for FIV.
He also said that although these are differant bugs and cannot be passed either way cat/human he did say that the way they work and their effects are exactly the same.
I just wonder if there is any useful information to be gained about HIV from FIV.
Geez people! I thought everyone knew that we already have an AIDS vaccine but the government is keeping it secret for population control or as a biological weapon. Or maybe they are just waiting for enough people to become infected that they can put it on the market and make a huge profit. I heard that it’s stashed right next to the files that say what really happened to JFK’s actual corpse (not the one buried in the cemetary). Of course, now I’ll probably disappear tomorrow…
There have been succesful trials of a SIV (simian IV) on animals. Tests of the corresponding HIV vaccine on humans will begin soon.
Note: This is to keep you from getting HIV. Vaccines generally are not intended to help after you get it. I think Daylon or his source is confused about this matter.
Err, “of a SIV vaccine …”
You have to keep up with the news.
This report shows that the complaint that we don’t have a vaccine for AIDS may well be time limited.
The main reason we don’t have one is that AIDS is an STD, and politicians think STD’s are icky, and don’t want to be seen as soft on moral issues. So, no federal funding for AIDS research for the first twenty years, let those perverts die, it will be better in the long run.
Tris
“Error of opinion may be tolerated where reason is left free to combat it.” ~ Thomas Jefferson ~
I saw some report that some people are naturally immune to AIDS because they lack some kind of receptors or something. Maybe someone can explain it better but I’d like to know if eno can get tested to see if he is immune.
sailor, were you thinking of Researchers isolate natural immunity to AIDS?
Here is an older reference to an actual study on a related theme (Adobe Acrobat required).