Christopher Glazek in The New Yorker:

ScreenHunter_346 Oct. 05 13.25In November, 2010, the New England Journal of Medicine published the results of a three-year clinical trial, funded by the National Institutes of Health, announcing the arrival of a treatment that could reduce the risk of contracting H.I.V. by more than ninety per cent. The treatment involved a blue, oval pill containing emtricitabine and tenofovir. Marketed under the brand name Truvada, the pill was synthesized in 2004 by Gilead Sciences, the world’s largest producer of branded H.I.V. drugs, and has been used in combination with other antiretrovirals as a primary treatment for people living with AIDS. The N.I.H. team discovered that a daily dose of Truvada not only suppressed the virus in people who were already infected but also prevented healthy people from contracting H.I.V. in the first place. Following the N.I.H. study, which tracked gay men in Peru, Ecuador, Brazil, South Africa, Thailand, and the United States, additional trials showed the drug to be effective for heterosexual men and women, as well as forinjection-drug users. Researchers called the treatment “pre-exposure prophylaxis,” or PrEP for short. Others have called it “the new condom.”

On the day the N.I.H. announced the results of the PrEP study, the research team received a congratulatory phone call from President Obama. Shortly thereafter, Time put PrEP in the first slot on its list of the year’s top medical innovations. Dr. Robert Grant, a professor at the University of California San Francisco and the N.I.H. study’s lead scientist, braced for a stampede. He told me, “The evening before we announced, we had meetings with the leadership of public health in California, and they were thinking, as we were, that there was going to be a rush, that everyone was going to descend on the clinics.” The Centers for Disease Control issued interim usage guidelines, despite the fact that the treatment was more than a year away from formal F.D.A. approval. The C.D.C. knew that some doctors were already prescribing Truvada for prevention off-label, and it expected more to follow suit.

But, in fact, adoption of the drug has been slow.

More here.