A New HIV Vaccine Shows Promise—but It Won’t Be a Silver Bullet

No silver bullets

Photo by Robert Cianflone/Getty Images

Researchers at Western University in Ontario, Canada, announced today that a newly developed HIV vaccine passed the first phase of clinical trials. That’s extremely good news, of course, but it should still be approached with a healthy dose of caution. The announcement doesn’t mean that scientists have discovered an effective vaccine against HIV—and even if they had, such a tool would be far from a silver bullet in the fight against AIDS.

If Western University’s vaccine actually works, it will, without a doubt, change the face of HIV prevention. A vaccine for the virus has been famously elusive; every trial thus far has failed, some disappointingly, some disastrously. The most effective trial produced a vaccine that’s just 31 percent effective, a figure low enough to make further trials impracticable. The worst, without a doubt, ended just last April, when doctors discovered that their vaccine might increase patients’ risk of contracting the disease.

So a vaccine whose effectiveness matched even, say, that of a flu shot (about 60 percent) would be a big deal. But the effectiveness of Western University’s vaccine remains a giant question mark, as researchers took the relatively unorthodox route of testing their shot on already-infected patients. The trial produced encouraging preliminary results: HIV-positive patients began producing exponentially more antibodies to attack HIV-related antigens. In other words, the vaccine kick-started patients’ immune systems, provoking them to fight back against a virus they would normally succumb to. And it did so without producing any adverse effects. That’s certainly auspicious. But it doesn’t necessarily follow that the vaccine will be as effective in preventing HIV-negative people from acquiring the virus. That question will be tested in the trial’s next phases.

In the meantime, it’s best to remain wary of purported HIV cure-alls. Every few months, doctors and scientists announce a purported cure for HIV: flooding newborns with antiretrovirals, say, or transplanting bone marrow. As a rule, these remedies are limited or one-off—not everyone has the luxury of a bone-marrow transplant, after all—but researchers can’t resist extrapolating upon their implications for the broader population. (How often are we told there will be a cure within months?)

That’s an understandable impulse, given how discouraging the field of HIV research can otherwise be. But trumpeting such announcements and speculating about their sweeping implications often distracts from more concrete and practical developments in the field. To wit: There is already a vaccine more effective than the flu shot at preventing HIV. It’s called circumcision. Research suggests circumcision reduces the risk of HIV acquisition by 60 to 70 percent over the course of one’s lifetime (if you’re straight, at least)—unlike a condom, which must be used properly during every sexual encounter. And while HIV-prevention circumcision drives are catching on in Africa, the circumcision rate in the United States is dropping dramatically. (This phenomenon is due in part to angry, though discredited, “intactivists.”)

Moreover, simple, commonsense measures to prevent HIV transmission like comprehensive sex education remain depressingly controversial in the United States. Americans who have received actual sex ed are significantly more likely to take measures to prevent HIV infection as compared to those who have received abstinence-only education. Yet many public schools are prohibited by conservative legislators from teaching basic HIV-prevention methods like condom use. Similarly controversial is HIV testing, which retains a stigma that dissuades Americans from learning their status. As my colleague Daniel Engber recently argued, we already have therapies that are “good enough to win the war on AIDS” through proper medication. But they rely on everyone learning their HIV status as early as possible—a sadly distant goal for our squeamish populous.

A world equipped with an HIV vaccine would unquestionably be a world with less HIV. But HIV prevention is a complex, multifaceted field, and it’s unwise to ignore the real solutions of today in favor of the possible miracles of tomorrow. If Western University’s vaccine is truly effective—and we do not yet have proof that it is—millions of people will likely avoid contracting the virus. But millions of people could also avoid it, and treat it properly, by using the tools available at this moment. We shouldn’t let the steady stream of purported breakthroughs divert our attention from the work at hand.