So what is taking so long? The road to an effective vaccine is littered with hurdles and barriers. Let's take a look at some of the challenges facing researchers in their quest to find a cure.
Which Immune Response Should Be Targeted?
The body's immune response is a complex combination of reactions to foreign invaders in the body. Researchers need to target the immune responses that will provide the most effective and long-term protection from HIV. Should specific responses be targeted or a combination of many responses? In order to develop an effective vaccine, this question has to be answered.
Which Type of HIV Should Be Targeted?
There are several HIV types. Subtle genetic differences change the virus enough to warrant different treatment approaches. If a vaccine is going to be truly effective and offer long term protection, it has to target a broad spectrum of HIV types. If the vaccine is too specific to one HIV type, its universal effectiveness will be diminished.
How Does Behavior Affect Vaccine Protection?
In laboratory testing, vaccines are tested in situations free of factors such as human behavior. As we all know, behavior is the hardest thing to change. The concern of many researchers is that vaccines effective in the controlled environment of clinical trials, will be less effective and offer less long term protection when human behavior is factored in.
Animal Model Testing
All vaccines must be tested on animals prior to being tested on humans. HIV vaccines offer a special challenge because animal models sometimes do not accurately predict human response. Changes need to be made in the experimental vaccines so they can be tested on animals. The issue is that often the vaccines that are changed for animal trials do not predict the vaccine's effectiveness in humans. Animal trials that truly reflect human response must be developed in order for vaccine testing to continue.
