The New York Times reported in an article this past Wednesday (http://www.nytimes.com/2010/11/28/weekinreview/28mcneil.html?pagewanted=1&_r=1&ref=health) that Truvada, a pill combining two well-established HIV treatment drugs, has been proven by an NIH-funded study to be “more than 90 percent effective” at preventing HIV infection when used every day by HIV-negative MSMs. While, on one hand, this sounds like a wonderfully promising discovery, it would perhaps serve us all well to exercise caution in estimating the potential of such a discovery to change the face of the global HIV/AIDS epidemic.
In an article on what we have learned in the last 30 years of fighting (and sometimes failing to fight) HIV/AIDS, Piot, Kazatchkine, Dybul, & Lob-Levyt (2009; see http://www.ifpma.org/documents/NR11754/Lancet_AIDS_Lessons_Learnt_20Mar09.pdf ) caution against single, “silver bullet” solutions to the problem of HIV/AIDS. They argue that regardless of any technological advances or new solutions, because of the varied and complex nature of HIV/AIDS epidemiology, comprehensive responses to HIV/AIDS will always include a complex set of multiple intervention strategies. We should therefore be wary of any promises of singular solutions. It follows, then, that we should be wary of the promises of a simple pill to effectively prevent infection on a wide scale basis. Let us first remember what drug companies stand to gain from the promotion of such a drug. If the drug is approved, won’t it essentially be recommended that the entire sexually active Sub-Saharan African population take the drug every day for the remainder of their sexually active lives, along with every other person or population in the world deemed to be at risk of contracting the virus? If so, pharmaceutical companies stand to make far more money on such a preventive drug than they would make on long-term treatment of HIV-positive individuals alone. Indeed, when the potential financial gain of pharmaceutical companies is considered, it seems as through Gilead Sciences (the company that produces Truvada) is offering us a magical, “silver bullet” solution to the problem of HIV/AIDS in exchange for the billions of dollars we will have to fork over to them in order to obtain it every day for the rest of our lives.
Even if we were to disregard the potential ulterior motives of drug-supply enterprises, there would still be ample reason to be skeptical of Truvada as a “silver bullet” solution to the problem of HIV prevention. Firstly, needless to say, the cost of supplying such a drug to the masses indefinitely would be staggering and essentially impossible to address in this time of global economic uncertainty. It therefore seems likely that the drug, although already available in many countries for HIV treatment, will be severely inequitably distributed as a preventive mechanism, with individuals able to pay for it outright receiving the initial supply, followed, perhaps, by high-risk populations within wealthy countries which can afford to subsidize distribution to those groups who they believe “need it” the most.
In general, preventive measures in developing countries most often take a backseat to treatment. This is especially true regarding HIV/AIDS treatment versus intervention in developing countries, as funding from global health initiatives like PEPFAR is overwhelmingly allocated to treatment, to the neglect of prevention. Such an expensive preventive intervention as a daily drug for all, then, will certainly be no exception to this rule. It therefore seems likely that developing, poorer countries will be the last to receive access to Truvada as a preventive mechanism. And when they do begin to receive and distribute the drug for prevention, they certainly they won’t receive anywhere near enough of it to distribute among the entire sexually active population. Yet in countries with generalized, wide-spread epidemics, universal availability would seem to be the desired level to which access to the drug should be scaled for maximum effectiveness. So, problems of inequality will abound, with the rich accessing the drug sooner, more consistently, and more easily, and the poor shut out from receiving the preventive pills, therefore reinforcing some of the very same social issues which are seen as underlying mechanisms perpetuating the HIV/AIDS epidemic.
Another important issue to ponder is the unlikelihood that the drug will reduce disease transmission by anywhere near 90%, as its promise of being “more than 90% effective” seems to suggest, even if the drug were somehow supplied to or available to everyone. As we all know, birth control pills are more than 99% effective, if used correctly. In practice, however, we have learned that “if used correctly” is a big “if”. We have ample evidence that inconsistent and incorrect use of something as simple as a daily birth control pill can result in pregnancies among more than 8% of women during their first year taking it (contracept.org), despite its 99% effectiveness estimate. And this finding holds in the United States, where relatively few barriers to access exist for those attempting to obtain this drug. It seems logical then, that we can expect an amplified version of this trend for the effectiveness of a daily dose of Truvada, once we factor in its initially lower effectiveness rate, its likelihood to be inconsistently accessed, and its necessity to be taken over many years. We should expect that the “typical use” effectiveness rate of Truvada, then, will be substantially lower than 90%.
It’s certainly nice to look into the future and see a world in which we all take a little Truvada pill in the morning and don’t trouble our thoughts with worries of disease or trouble our romances with conversations of monogamy and safe sex practices. But in my opinion, it’s not realistic. Long-term, universal, daily use of an HIV-prevention drug is simply not economically sustainable. And even if it were, it seems unlikely that Truvada’s effectiveness for preventing HIV infection will be anywhere near as high as suggested by the initial study findings. Condoms have a higher efficacy rate for HIV prevention than does Truvada. So, if we humans have provided ample evidence that we will not consistently wear condoms to prevent HIV infection or even consistently adhere to treatment once we actually become HIV-positive, then why does Gilead Sciences expect us to believe that they can solve our problems and save us with a daily dose of an expensive drug (that many of us simply won’t take with enough consistency to do any good)? Perhaps the answer is not in the “silver bullet” promise, but in the silver Gilead Sciences expects to be paid.