Sean Philpott: Preparing for PrEP
An estimated 34 million people around the world are infected with HIV, the virus that causes AIDS. Most of these individuals live in developing countries, but approximately 1.2 million Americans are infected. At least of third of those living with HIV/AIDS in the US are unaware of their status.
Most of those infected with HIV globally are socially or economically marginalized. In the United States, for example, almost two-thirds of all new HIV infections occur among gay and bisexual men. In regions of the world like Africa and Asia, by contrast, many are women who lack the resources to leave relationships that put them at risk.
This marginalization often makes the current set of HIV prevention tools – condoms, abstinence or mutual monogamy – inaccessible to those most at risk. Given this, HIV prevention researchers are working on developing new, inexpensive and user-controlled tools that will enable these individuals to protect themselves, and have recently achieved some measure of success.
Four large-scale clinical trials in the United States, Latin America, Africa and Asia have demonstrated the effectiveness of pre-exposure prophylaxis (also known as PrEP) for HIV prevention. PrEP involves use of an antiviral drug like Truvada – already on the market as a treatment for HIV – by otherwise healthy individuals who are at increased risk of contracting the virus. Studies suggest that a daily dose of Truvada can cut an individual’s risk of HIV infection by 40 to 75 percent.
Based on the results of these studies, many doctors in the United States and Europe are already prescribing it to their patients for prevention. The manufacturer of Truvada has also applied to the US Food and Drug Administration for approval to market the drug for HIV prevention as well as treatment, a position that was supported by a panel of FDA experts. The FDA is expected to issue its ruling in early September.
Not all HIV/AIDS advocacy groups, however, support the widespread use of an antiretroviral drug like Truvada for prevention. The AIDS Healthcare Foundation, the largest non-profit provider of HIV treatment and care in the US, fears that these drugs pose an unacceptable health risk for otherwise healthy individuals. Known albeit rare side effects of Truvada can include kidney disease and liver failure. Those risks might be acceptable to someone living with HIV/AIDS who might otherwise be ravaged by the disease, but not to those using the drugs solely for prevention.
In addition, groups like the AIDS Healthcare Foundation worry that widespread use of drugs like Truvada for prevention could paradoxically increase the spread of HIV. PrEP is not 100% effective. Those using it must take their pill every day, must continue to engage in safer sex practices, and must get tested for HIV regularly. The fear is that those using PrEP could be lulled into a false sense of security, and thus engage in risky behaviors that make it more (not less) likely that they will acquire HIV. This fear is not misplaced. Several surveys found that a significant percentage of the gay and bisexual men who expressed an interest in using a drug like Truvada for HIV prevention also reported that they would decrease their condom use.
Despite these fears, current public health models suggest that PrEP can be an effective HIV prevention tool. According to these models, that the most cost-effective PrEP programs are those that target well educated, urban-dwelling gay and bisexual men specifically. The drugs themselves, and the follow up testing and counseling necessary to ensure their safe and appropriate use, will provided by primary care physicians and paid for by private insurance plans.
Unfortunately, such programs will miss the groups who most desperately need new HIV prevention tools like PrEP. Studies of PrEP use and acceptability found that those most likely to be willing to use antiviral drugs for HIV prevention are predominantly white. However, some of the highest rates of HIV infection occur among men of color. Nearly 60% of new infections now occur among black and Latino men, many of whom live in the rural South and do not self-identify as gay or bisexual. HIV prevention efforts that target gay and bisexual men specifically may overlook this key at-risk group.
Moreover, high rates of HIV infection among racial and ethnic minorities in the United States are not limited to gay and bisexual men. The rate of new infections in the African American community as a whole is almost ten times that of whites, and that of the Hispanic community is nearly three times that of whites. Hispanic and black Americans are also far less likely than whites to have health insurance or to have a usual source of medical care. These groups are in danger of being left behind by programs that fail to target them specifically or that they cannot access due to existing inequities in healthcare.
Despite these concerns, I do hold out hope that PrEP will be a useful new weapon in the fight against HIV/AIDS. Rates of new infection in the US have remained steady for the past decade, and have even increased among some groups, suggesting that current HIV prevention programs are of limited effectiveness. The challenge will be in incorporating PrEP into current programs in a way that not only enhances HIV prevention efforts but also addresses the needs of the most vulnerable and at risk groups, namely historically disadvantaged racial and ethnic minorities.
A public health researcher and ethicist by training, Dr. Sean Philpott is a professor of bioethics at Union Graduate College in Schenectady, New York. He is also the Chair of the US Environmental Protection Agency’s Human Studies Review Board, which reviews all research involving human participants submitted to the EPA for regulatory purposes.
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