In the 1980’s, shortly after the HIV virus was isolated as the cause of the terrifying unexplained disease AIDS, Ronald Reagan’s Health and Human Services secretary famously suggested that a vaccine would be available within two years. Fast forward 30 years and we are still waiting.
Why is it so difficult? Well, HIV is the most antigenically variable pathogen known, so vaccinating against one strain only gives you a 1 in thousands chance to protect you against any of the thousands of different strains circulating in the world you might be unfortunate enough to encounter. Also, that variability has allowed the virus to interrogate a whole host of mechanisms for battling the immune system, many of which may remain unknown.
Thanks to antiretroviral drugs (ART), the pressure has been off a bit since the 1990s. In fact, recent studies showing that a person on ART is protected from HIV infection even got people wondering whether it was even worth the apparently futile effort to develop an HIV vaccine.
But its always darkest before the dawn. At its lowest point, a misfit clinical trial succeeded in showing a statistically significant reduction in HIV acquisition. Why misfit? Well, this trial vaccine was a combination of two vaccines that had previously failed. Two wrongs DO make a right! Or at least they do better than the host of scientists burning through 90% of the billions of dollars wasted on the “right” ways.
The RV144 clinical trial remains the only HIV vaccine clinical trial to show vaccine protection from HIV. Sometimes you can be too smart for your own good.