SAN FRANCISCO - Over a cup of tea at a downtown Starbucks, Michael Rubio recalled how four friends became H.I.V. positive through unprotected sex, all within a year. The news shocked Mr. Rubio, a 28-year-old gay man, into trying a controversial new form of H.I.V. prevention: a daily pill that studies show is highly effective in protecting people from infection.
“With my inner circle so affected in the last year, it was a no-brainer to consider this for my life right now,” said Mr. Rubio, a front-office coordinator at the Positive Resource Center, a social service agency for people with H.I.V.
The very existence of that option represents a startling turn in the too-long history of the AIDS epidemic. Many health experts hoped that the medication — Truvada, a combination of two antiviral drugs that has been used to treat H.I.V. since 2004 — would be exuberantly embraced by H.I.V.-negative gay men. Instead, Truvada has been slow to catch on as an H.I.V. preventive in the 18 months since the strategy’s approval by the Food and Drug Administration. In some quarters, the idea that healthy gay men should take a medication to prevent infection — an approach called pre-exposure prophylaxis, or PrEP — has met with hostility or indifference.
“It’s gotten tons of attention at H.I.V. meetings as a new tool for prevention, and I consider it an important option for the right person,” said Dr. Lisa Capaldini, a primary care doctor here who treats many gay men. “And yet there’s been very little interest among my patients. There’s a fascinating disconnect.”
For 30 years, public health officials have aggressively promoted condom use during every sexual encounter as the only effective method, apart from abstinence, for preventing H.I.V. transmission. Still, 50,000 new infections are occurring annually in the United States; sexual transmission between men accounts for more than half of them, and a disproportionate number among African-Americans and other minorities.
Many experts hailed Truvada as an opportunity to reduce new infections among high-risk groups like young gay men, people in relationships with H.I.V.-positive partners, and prostitutes. The F.D.A. called for prescriptions to be accompanied by counseling, frequent H.I.V. testing, and continued promotion of safer sex, although research suggests that daily use of the pill alone confers close to full protection.
For many gay men, and for some public health officials, the new option has brought both hope and confusion.
“We’ve had several decades of the recommendation to use condoms,” said Dr. Kenneth H. Mayer, a professor of medicine at Harvard University and the medical research director at Fenway Health, a community center in Boston with many lesbian and gay patients. “Now we’re saying, ‘Here’s a pill that might protect you if you don’t use condoms.’ So it’s flying in the face of community norms.”
Certainly, fewer people have tried PrEP than many experts had anticipated. According to an analysis by Gilead Sciences, which makes the drug, data from more than half of retail pharmacies nationwide indicated that 1,774 people filled prescriptions for Truvada for H.I.V. prevention from January 2011 (it could be prescribed off-label before the F.D.A. approval) through March 2013. The numbers did not include the thousands already receiving the drug as research participants.
Almost half of the prescriptions were for women, a surprise to those who expected gay men to be the early adopters. Dr. Deborah Cohan, an obstetrician and gynecologist at the University of California, San Francisco, has prescribed it to several women with H.I.V.-positive partners, including one seeking to get pregnant.
“It’s beautiful that we have this intervention that works for women who need it,” Dr. Cohan said.
So why haven’t more gay men signed up?
Some men have reported receiving negative reactions from their health care providers when they brought it up. Use of the drug as a preventive can be stigmatizing among gay men as well: the term “Truvada whore” has been bandied about on some social networks.
And many simply may not know much about the strategy. Gilead has not launched a public campaign to market Truvada for prevention, but has instead sponsored activities by other organizations. Fenway Health, for example, has received Gilead funding for some PrEP-related education and research.
Potential side effects like kidney damage and a loss of bone density, although rare, are also a concern. And Truvada is expensive: more than $1,000 a month. So far, private and public insurers, including state Medicaid programs, have generally covered the drug for prevention. (Gilead also provides it to some patients who cannot afford it.)
But a generational shift in attitudes toward H.I.V. among gay men may also be playing a role, some experts say. With advances in treatment, many younger men who did not experience the worst years of the epidemic are less fearful of the consequences of infection. Moreover, current medications can lower viral levels in H.I.V.-positive people to the point where the risk of transmission is negligible, further reducing the perceived need for PrEP among H.I.V.-negative partners.
Damon Jacobs, a New York psychotherapist, began taking Truvada following the breakup of a long-term relationship. “I found that I was no longer as consistent with condom use as I had been in earlier days, and that scared me greatly,” said Mr. Jacobs, 42, who maintains a Facebook page promoting PrEP. He said that he has not missed a dose in two years; he also acknowledged that he was now much less likely to use condoms.
That sort of acknowledgment makes some health care experts nervous, despite Truvada’s efficacy when used daily. The AIDS Healthcare Foundation, a major H.I.V. services provider based in Los Angeles, lobbied against F.D.A. approval of Truvada for H.I.V. prevention, arguing that men taking the medication would be likelier to pursue riskier sexual practices.
Certainly, “condom fatigue” among gay men is real. The proportion who reported unprotected anal sex in the previous year rose to 57 percent in 2011 from 48 percent in 2005, according to the Centers for Disease Control and Prevention.
But a recent study found that men in a large clinical trial who believed they were taking Truvada rather than placebo did not increase their risky behavior. For his part, Mr. Rubio, the San Francisco coordinator, said he remained “adamant” about using condoms. “For me, this is a whole other layer of protection,” he said.
Adherence to the drug regimen is another thorny issue. The major trial that confirmed Truvada as an effective H.I.V. preventive among men who have sex with men, also found that many participants did not take the pill every day, leaving them more vulnerable to infection.
Michael Weinstein, president of the AIDS Healthcare Foundation, warned that drug adherence will continue to be a problem, likely leading to more infections and the emergence of drug-resistant H.I.V. strains. “If you don’t take the medication every day and you don’t use condoms, and you’re highly sexually active, you’re going to get infected,” Mr. Weinstein said.
Advocates for PrEP argue, without substantial evidence to date, that people now taking and starting Truvada for prevention may be more likely to follow instructions because they know that it works, unlike participants in the early clinical trials.
In any event, the protocol for pre-exposure prophylaxis is itself likely to undergo significant changes as findings emerge from current and upcoming research into other formulations of Truvada such as gels or injectables, less frequent dosing regimens, and the use of other medications altogether.
“People are not lining up, but I’m not pessimistic,” said Dr. Mayer of Fenway Health. “It’s going to take time. It’s really early days.”
This article has been revised to reflect the following correction:
Correction: December 31, 2013
An earlier version of this article referred incorrectly to Michael Weinstein, president of the AIDS Healthcare Foundation. Though he has an honorary doctorate degree, he is not a medical doctor and therefore is not Dr. Michael Weinstein.