It is a matter of time before researchers wipe HIV from the continent, giving a lifeline to millions of victims.
For just the second time since the global epidemic began, a patient appears to have been cured of infection with HIV, the virus that causes Aids.
The news comes nearly 12 years to the day after the first patient known to be cured, a feat that researchers have long tried, and failed, to duplicate.
The surprise success now confirms that a cure for HIV infection is possible, if difficult, researchers said.
The investigators are to publish their report Tuesday in the journal Nature and to present some of the details at the Conference on Retroviruses and Opportunistic Infections in Seattle.
Publicly, the scientists are describing the case as a long-term “remission.” In interviews, most experts are calling it a cure, with the caveat that it is hard to know how to define the word when there are only two known instances.
Both milestones resulted from bone-marrow transplants given to infected patients. But the transplants were intended to treat cancer in the patients, not HIV.
Bone-marrow transplantation is unlikely to be a realistic treatment option in the near future.
Powerful drugs are now available to control HIV infection, while the transplants are risky, with harsh side effects that can last for years.
But rearming the body with immune cells similarly modified to resist HIV might well succeed as a practical treatment, experts said.
“This will inspire people that cure is not a dream,” said Dr. Annemarie Wensing, a virologist at the University Medical Center Utrecht in the Netherlands. “It’s reachable.”
Wensing is co-leader of IciStem, a consortium of European scientists studying stem cell transplants to treat HIV infection.
The consortium is supported by AMFAR, the American Aids research organisation.
The new patient has chosen to remain anonymous, and the scientists referred to him only as the “London patient.”
“I feel a sense of responsibility to help the doctors understand how it happened so they can develop the science,” he told The New York Times in an email.
Learning that he could be cured of both cancer and HIV infection was “surreal” and “overwhelming,” he added. “I never thought that there would be a cure during my lifetime.”
At the same conference in 2007, a German doctor described the first such cure in the “Berlin patient,” later identified as Timothy Ray Brown, 52, who now lives in Palm Springs, California.
That news, displayed on a poster at the back of a conference room, initially gained little attention.
Once it became clear that Brown was cured, scientists set out to duplicate his result with other cancer patients infected with HIV.
In case after case, the virus came roaring back, often around nine months after the patients stopped taking antiretroviral drugs, or else the patients died of cancer.