Truvada has been approved for people who have been exposed to the virus but are not yet infected. (Joel Saget/AFP/Getty Images)

Nick Gourdine headed to his doctor’s office from his apartment in Southeast Washington one day in 2011 with HIV on his mind. He’d hooked up with a friend, someone he thought he knew but who turned out to have withheld a crucial bit of information: He was HIV-positive. Now Gourdine worried that he was, too.

His HIV test came back negative. To keep it that way, Gourdine, a 35-year-old youth program manager, became an early user of a combination drug to ward off HIV infection that has generated excitement and discussion among scientists and activists.

The drug, Truvada, and the prevention approach, called pre-exposure prophylaxis, or PrEP, are increasingly at the center of efforts to keep such people as Nick negative. While the Food and Drug Administration approved Truvada for PrEP in 2012, only a few thousand people currently take it, according to the drug’s maker, Gilead Sciences. The Centers for Disease Control and Prevention estimates that at least 500,000 could benefit from it.

About 50,000 Americans are diagnosed with HIV every year, according to CDC statistics from 2011. That year, the number included 959 people in the District.

And while some have worried that increased use of a pill to prevent HIV may encourage risky behavior, leading to decreased condom use and increases in other sexually transmitted infections, the approach is being embraced by government agencies that are funding campaigns to promote widespread use. This new phase of the prevention effort, spearheaded in states and municipalities including the District, Washington state, New York and California, is being watched by officials nationwide to see which efforts work.

The Centers for Disease Control and Prevention estimates that at least 500,000 people could benefit from early use of drugs such as Truvada. (Photo Illustration by Justin Sullivan/Getty Images)

“PrEP is a bullet train that, frankly, has already left the station,” said Terrance Moore, director of policy and health equity at the National Alliance of State and Territorial AIDS Directors, which helps guide HIV treatment and prevention policy. “Now it’s about setting up systems and educating people about PrEP — both people taking [Truvada] and providers.”

Truvada works by coating the cells of the immune system, blocking the HIV virus from gaining a foothold, said Christopher Chauncey Watson, clinical research site director in the Department of Epidemiology and Biostatistics at George Washington University.

A highly effective drug

It is more than 90 percent effective when taken daily. The CDC guidelines call for a negative HIV test before prescription — to avoid creating a strain of HIV resistant to at least one of the drugs in Truvada — as well as quarterly tests for HIV, STD, kidney function and, for women, pregnancy.

The drug is generally well tolerated. Nausea, dizziness and headaches usually subside in the first month; there’s also a mild risk of kidney damage and bone mineral density changes, said Dawn K. Smith, head of biomedical interventions activity in the epidemiology branch of CDC’s Division of HIV/AIDS Prevention.

“There hasn’t been any significant [kidney] disease seen in any of the thousands of participants in the trials,” Smith said. In a Thai study that followed people who used Truvada prophylactically for up to five years, Smith said, none of the participants developed kidney trouble.

About 2,300 Americans were prescribed Truvada for HIV prevention in 2012 and 2013, the latest period for which Gilead has released statistics. Of those, 48.8 percent were women, and 32 percent lived in the South.

This is important. Forty-five percent of new HIV diagnoses are in the South, more than any other part of the country, according to 2010 statistics from the CDC. African American women are 20 times as likely to contract HIV as white women due in part to many living in communities where HIV is poorly controlled or monitored. Gay African American men have almost as many HIV diagnoses as all new diagnoses among white gay and bisexual men combined, despite representing a far smaller proportion of the population, according to the CDC.

While a growing number of HIV diagnoses are happening in the South, it’s Northern agencies that so far are taking the lead on PrEP.

New York Gov. Andrew Cuomo (D) included access to PrEP as one approach to drastically cutting new HIV infections by 2020. Washington state is spending $2 million a year to cover PrEP costs for residents, whether insured or uninsured. Truvada can cost $13,000 a year, according to Gilead — and although the company will provide it for certain people without insurance, the process for getting that aid can be daunting and not everyone qualifies. Medicaid also covers the drug for some low-income people.

Very costly

Meanwhile, some people with insurance are finding that Truvada can be unaffordable. Last week, San Francisco’s Board of Supervisors voted to spend about $300,000 to provide staff to help people with high co-payments or high deductibles obtain maximum coverage for the drug.

Michael Kharfen is watching all this from his office at the D.C. Department of Health.

“We want to see how they do,” said Kharfen, senior deputy director of the department’s HIV/AIDS, Hepatitis, STD and TB Administration.“That’s the next phase — getting the pharmaceutical drug assistance piece. The first part will be educating and engaging the community.”

A 2012 study of gay men that the department conducted found that only a third had heard of PrEP, but once they knew about it, 78 percent said they’d be interested in using it.

The department awarded $300,000 to Whitman-Walker Health and Andromeda Trans­cultural Health last month to educate potential users and providers about PrEP, reach out to the people at highest risk for HIV and develop plans to address the risk of other sexually transmitted diseases.

Kharfen, the self-described “condom guy of D.C.,” sees PrEP as complementary to the wide distribution of condoms. His department distributed 6.9 million condoms last year, he said.

“This is not a question of if you [promote] PrEP, it’s the end of condoms, or ignore PrEP and do only condoms,” Kharfen said. “You’ve got to support people to do what works for them.”

When Nick Gourdine began Truvada, his provider peppered him with questions: How many people had he slept with? How often did he use condoms? How many of his partners were HIV-positive? How often did he not know his partner’s status?

The answers painted a “gruesome picture,” he said. (His insurer pays for the drug completely.)

For Gourdine, his use of Truvada coincided with mental health therapy and a growing comfort with his sexuality. He’s having sex with fewer people and is pickier about who they are.

“PrEP is helping to save lives,” he said. “It’s been a factor in saving my life, too — not just physically but also emotionally.”

Boerner is a journalist and the author of “Positively Negative: Love, Pregnancy, and Science’s Surprising Victory Over HIV.”