by Eleanor Ball
For many epidemiologists, a vaccine for HIV is the biggest dream they have been chasing for years. A recent trial of a potential vaccine was providing tantalizing hope to researchers before it was cancelled on February 3rd, dashing the hopes of many.
This HIV vaccine is the one that has demonstrated the most promising hints of working so far, but those hints did not translate into tangible results. Researchers began a trial of it in October 2016, sponsored by the US National Institute of Allergies and Infectious Diseases (NIAID). 5,407 sexually active, HIV-uninfected men and women across South Africa were included in the study. Half received placebos, and half received the vaccine. Unfortunately, the rate of HIV infection in the two groups was nearly identical: 123 individuals in the placebo group contracted HIV, and 129 individuals in the vaccinated group contracted HIV. The study was supposed to continue until July 2022, but an independent NIAID monitoring board announced this month they would end the study early because they found the vaccine ineffective.
This attempt at an HIV vaccine had its roots in a previous study in Thailand. A similar vaccine tested there decreased infections by 31%. While researchers agreed that result wasn’t good enough to bring the vaccine to market, they disagreed over whether or not it was promising enough to pursue in another study. In the end, a team of researchers headed by Glenda Gray, President of the South African Medical Research Council, decided to follow this path. They developed a modified version of the Thailand vaccine and elected to test it in South Africa because of how widespread HIV is there--around a fifth of adults live with the disease. Although their vaccine was not successful, their work in South Africa is not done: they will continue to track those who participated in the study to try to decipher why the vaccine failed.
When hearing of the failure of this promising vaccine, some elements of society may be tempted to take this as a sign that vaccines do not work. If this was the most--really, the only--promising HIV vaccine, they might say, and it failed so spectacularly, shouldn’t that be taken as a sign that vaccines should not be bothered with at all? However, that is not a sound position. The nature of scientific inquiry is that it often fails wholly or partially many times before it gets the whole picture right. Just because this particular vaccine did not work and it was viewed as the most promising lead a year ago does not mean there will never be a functional HIV vaccine; there are still many more formulations and approaches to try.
In a similar vein, it is important to not take away from this news the idea that the study was not useful just because the vaccine itself failed. Although the information researchers got from this study was not the information they were hoping for, it will still be useful for future research nonetheless. They now know much more about the kinds of vaccines that are ineffective for HIV and, therefore, have good ideas about what they should try next and where they are likely to find future success. They can now better target valuable resources, focusing instead on vaccines that trigger different immune and antibody responses. Susan Buchbinder, an epidemiologist at the University of California, San Francisco, highlights this in her comments on the study: “The trial was incredibly well done and we got a definitive answer, and that's what science is about.”
In the aftermath of the study, other researchers defend it by emphasizing the ethical need to do everything in their power to help alleviate the HIV crisis, which is so devastating to millions of people. Although Gray expressed desolation at the study’s cancellation, she also emphasized the importance of having attempted this kind of intervention. Anthony Fauci, NIAID Director and backer of the study, agrees. He says the immense need across the globe for a working HIV vaccine compelled the researchers to back the study, and he has no regrets about doing so.
“I don’t think it was a bad choice,” says Fauci. “I think it was the only choice.”
Eleanor Ball is a GW Scope staff writer and junior humanities editor for the George Washington Undergraduate Review. She is currently researching 17th century Flemish art and the relationships between period innovations in science and aesthetics. A freshman studying international affairs and public health, she is also on the board of GW Shakespeare and a member of GlobeMed and the Politics & Values program.
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