Almost 40 years and still no HIV vaccine. The first clinical trial of a preventive HIV vaccine began in 1987. Since then, between 100 and 250 vaccine candidates have been developed and tested using animals, yet every one has failed in human trials. Progress has been hindered by HIV’s extraordinary ability to evade immune defenses and the complexity of the human immune response to the virus. Compounding these challenges, trial designs—both in animals and humans—have often been inconsistent and poorly documented.
Only humans contract HIV and develop AIDS. To sidestep this critical detail, experimenters instead infect monkeys with simian immunodeficiency virus (SIV), a virus unique to African primates. However, SIV shares only about 55% genetic homology with HIV and is less genetically diverse. Because of differences in surface proteins and other molecular features, antibodies that neutralize SIV rarely work against HIV, and vice versa. Experimental infections in nonhuman primates typically involve doses of SIV far higher than the amount of HIV-1 a human would encounter during sexual transmission.
The promise of an HIV vaccine has killed thousands of macaques. Many of these animals—some endangered—are torn from their natural habitats and subjected to grueling journeys before arriving in U.S. laboratories. Some later prove to be carrying infections such as Valley fever, which can confound HIV experimental results. Others are bred into a life of deprivation in a laboratory, stripped of everything essential to their species. They endure painful procedures and induced illnesses before being killed. This doesn’t even account for the countless other species subjected to similar suffering—animals for whom we have no reliable estimates of their numbers—or the the human lives lost to AIDS while waiting for science that delivers.
After all that progress, it’s heartbreaking to see science still stuck in outdated methods.
Experiments on animals continue to dominate #HIVresearch, even though they fail to reflect the complexity of the virus or the human immune system.
#AIDSresearch #EndAIDS #GlobalHealth #PublicHealth
