My professor said something two days ago that shocked me: “I honestly don’t think we’ll ever see an effective vaccine for HIV/AIDS.”
Considering how much of an expert he is, that was pretty demoralizing. And I don’t believe him; I can’t believe him. Too much is at stake.
Yet to date we’ve spent billions of dollars, and we’re not much closer to a vaccine for AIDS. All we’ve learned are several ways that don’t work. Here’s why.
The general idea around vaccines is that they prime the immune system to respond to invasion rapidly and efficiently. So the smallpox vaccine makes your body quickly attack invading smallpox viruses, and so on.
A quick immune response is extremely important because it typically takes more than a week for your body to respond fully to infections, and by that point you may be dead or paralyzed, like with polio.
Vaccines have also typically been against parts of the virus that don’t change, like the envelope that coats viruses as they float around in the blood, waiting to infect new cells.
Both of those ideas fail with HIV. First, there has been not a single person who developed AIDS and then healed from it fully – to the point where there is no virus left in their body. This is in spite of the fact that someone infected with HIV does in fact launch a full scale immune attack on it.
So if our immune systems are incapable of defeating HIV, a vaccine won’t necessarily do anything. The body’s soldiers will start fighting sooner but still lose the war.
Additionally, it has been extremely difficult to develop a vaccine against the parts of HIV that have worked for other diseases. This is for several reasons.
First, HIV shields itself from being targeted by covering itself in proteins taken up from the cell that it grew out of. This is like having a cloaking device. And the part of HIV that is unique to it, the complex that attaches it to cells to allow invasion, is withdrawn until the last possible moment. That means it is nearly invisible to the body.
As if that weren’t enough, HIV mutates rapidly. Those mutations create changes in the structure of the virus so fast that the immune system simply can’t keep up. It launches antibodies that are targeted against one strain of the disease, wipes that one out, but another strain entirely simply replaces the previous one.
For these reasons and more, despite the billions of dollars spent on research, we have had only one vaccine so far that showed any efficacy at all, and even those moderately positive results may not actually mean anything.
The reason that it has been so unsuccessful is because our classical approach to vaccine development simply does not work for HIV.
That said, I believe we shouldn’t give up hope yet. There are additional targets for vaccine development that have yet to be tried, especially the tat gene and product. And there are exciting new methods of vaccine delivery and design that may allow better targeting and response.
We can’t give up. More than 25 million people are currently infected with HIV, and that number is only rising. The lives of millions of people depend on us finding an answer to this problem.
We will next consider and discuss the HIV tat gene, which is, I may naively believe, an exciting new approach to vaccine development.