However, some experts argue that people taking Truvada for HIV prevention will forego condoms or that improper use of Truvada could lead to the emergence of resistant strains of HIV.
There's also headway being made in improving access and uptake of HIV testing. The goal: "Radically expanding testing so we don't have people who don't know their HIV status, and if you are HIV-positive, you are [then] linked to effective care," Vermund said.
Experts estimate that about one in five people who has HIV does not know it and three recent studies, including one by Vermund and his colleagues, found that only about one-quarter of people with HIV are keeping the virus in check with antiretroviral drugs. Data like that was "a wake-up call" that more needed to be done, Vermund said.
There's good reason to find out your HIV status early, since newer antiretroviral drugs now carry lower risk of side effects, noted Stephen Gange, a professor of epidemiology at Johns Hopkins University, in Baltimore. "I think everyone felt comfortable that they could be used fairly widely," he said.
Another milestone in HIV/AIDS care was achieved earlier this month, when the FDA approved the OraQuick In-Home HIV Test, the first test that can give a person rapid results on his or her HIV status in the privacy of their own home.
Better access to testing, better outcomes
San Francisco may be ahead of the curve in testing and treating, Vermund said. In 2010, the city announced that any resident living with HIV would be directed to antiretroviral therapy even before they show signs of advancing disease. New York is the only other city to have announced this policy, in December 2011.
Since 2010, the San Francisco Department of Public Health has intensified its efforts on routine HIV testing in emergency rooms, doctors offices and storefront testing sites in high-prevalence neighborhoods, unless patients want to opt out, said Dr. Moupali Das, director of research for the department's HIV Prevention Section. And if a person tests positive for HIV, the testing site and clinic now communicate with each other to ensure the person receives care, she added.
The result: the proportion of gay and bisexual men who did not know they were HIV-positive has dropped from about 20 percent in 2004 to only 8 percent in 2011, Das said.
"HIV in the U.S. is not a homogenous epidemic. It's lots of tiny little epidemics affecting different groups of people and different geographies in different ways," Das said.
In the United States, HIV has the biggest impact on gay and bisexual men. Black men in this group make up a quarter of new HIV cases. Among women infected HIV, black and Hispanic women made up more than three-fourths of new cases in 2005.
A new study is under way in the Bronx, in New York City, and in Washington to promote testing in these areas, with special messages for gay and bisexual men, and to determine whether incentives like receiving gift cards make people more likely to visit their clinic and take their medication as directed.
"Like many others, I would be delighted to have an AIDS-free generation, but I think we really need to think that we can't rely on [only] one strategy," Ganges said.
In the meantime, researchers seeking to adapt the cure of the "Berlin patient" are still in the early stages of trying to figure out how to target the appropriate cells without harming others, Johnston said.
A vaccine for HIV also remains a possibility, although no one expects it anytime soon. One 2009 vaccine trial in Thailand reduced HIV infection rates by about 30 percent, which is the first evidence that an HIV vaccine might be effective, said Rick King, vice president of AIDS vaccine design at the International AIDS Vaccine Initiative, in New York City.
More studies have to be done to get a better idea of how much protection this vaccine offers, as well as whether it would work in populations like the United States. But even if it all goes smoothly, it would probably be close to 10 years before this vaccine were deployed to the public, King said.