In the early 2000s — the beginning of the third decade of the AIDS epidemic--the world came together in an unprecedented global health effort to provide life-saving AIDS drugs to people even in the poorest corners of the world. It has been an overwhelming public health success story. In 2000, fewer than a million of the then 34.3 million people with AIDS were being treated with AIDS drugs, and almost all of them lived in wealthy countries. Today, 20.9 million of the 36.7 million people with AIDS receive treatment, according to UNAIDS, most of them living in the poor countries where the disease is most prevalent. In the view of the public health community, reducing the prices on AIDS drugs and setting up the infrastructure to distribute them to people in poor countries in less than two decades is seen as phenomenal and unprecedented.But that's treatment. Prevention efforts are a different story, and if the world doesn't figure out how to prevent new cases of HIV, stubbornly holding steady at about two million infections a year since 2005, according to a 2016 report in Lancet HIV, a resurgence in the epidemic is possible. That gloomy warning comes from a report by a new Lancet Commission led by the International AIDS Society and published in the July 19 Lancet justdays before the start of the 22nd International AIDS Conference on July 22 in Amsterdam. The report finds that efforts to prevent the spread of HIV have stalled, in part, because international funding for AIDS has begun to decline. What's more, a key finding of the report is that "the HIV pandemic is not on track to end, and the prevailing discourse on ending AIDS has bred a dangerous complacency and may have hastened the weakening of global resolve to combat HIV.""We're really not seeing the declines in new infections that people were hoping would happen by now," says Dr. Chris Beyrer, epidemiologist with the Johns Hopkins Bloomberg School of Public and an author of the report. "And there are worrisome signs of an expanding epidemic in some populations."The populations most at risk are the same groups that were considered at high risk at the start of the epidemic in the early 1980s: gay and bisexual men, transgender people, people who inject drugs, sex workers and the sex partners of people in those groups, according to the report. And those are the people most likely to resist going to the kinds of health centers that provide AIDS services. In many parts of the world, AIDS testing and care has been provided in stand-alone AIDS clinics, apart from other health services. But many people who are at highest risk for AIDS feel unwelcome, or simply will not go, to designated AIDS clinics because of stigma still surrounding the disease, says Beyrer. Or they don't go because the clinics won't address their complete health needs. "I met a guy in Ukraine who was dealing with addiction, HIV and TB. All the services he needed were in three centers,100 kilometers from each other," says Beyrer. "You have TB clinics that won't treat HIV; or HIV clinics that won't treat people who are high." People need health centers that will care for all their needs, the paper's authors argue. So the study's researchers used present-day statistics to project probable results of different types of care settings into the future. What if, for example, a country with high rates of diabetes and heart disease combined blood pressure and diabetes screening with HIV screening? What if a country with high rates of unplanned pregnancy screened women for HIV as they offered family planning services? What if areas of high IV drug use offered needle exchange programs alongside AIDS services? In Russia, for example, injection drug users are at high risk for AIDS. So researchers examined the potential benefits of combining AIDS services with clean needle exchange programs. In such a model, using data from needle exchange research, drug users found to be HIV infected could start antiretroviral treatment, or ART, which helps prevent transmissionof AIDS at the same time they used needle exchange services. Researchers showed that such a hypothetical combination of services could avert as many as half of new cases of HIV in the next ten years in the two areas of Russia they examined. And in Nigeria, researchers estimated what could happen if HIV services were provided in family planning centers. Nigeria accounts for about a third of all mother to infant HIV infections in the world. "It's a huge problem in Nigeria," says Beyrer. "And they also have an enormous unmet need for family planning. So it's not rocket science to integrate AIDS services with maternity care and family planning centers." Combining those health services, the study found, could prevent 300,000 new HIV infections over the next ten years in Nigeria.The report's finding that HIV prevention efforts are lagging sends an important warning to the world, says Dr. George Seage III, professor of epidemiology at the Harvard T.H. Chan School of Public Health. He was not involved in the new Lancet report. "It's important to dispel the assumption that the end of HIV is near. We're not there yet," he says. "The prevention initiatives have lacked funding and enthusiasm. Like any infectious disease, it doesn't take much to have it spike again, and [we would] lose all that we've gained." The report's recommendation that AIDS services begin to be offered alongside other health services might prove necessary, but it's risky, says Seage. "Whatever success we've had with slowing the epidemic with treatment might be diluted," he says. "What made it successful was the focus on HIV. If we start integrating testing and treatment into general health care, we might lose that laser focus."No one can afford to get complacent about AIDS, says Carl Sciortino, executive director of AIDS Action, a division of Fenway Health, in Boston. "We've seen an overall statewide decrease in infections of about 50 percent since 2000," he says. "But the reduction is not even. There are increasing rates of infection in young black and Latino people." And the opioid epidemic has hit parts of Massachusetts hard, Sciortino says, possibly accounting for a slight uptick reported by the Massachusetts Department of Public Health in the number of new HIV infections in IV drug users, from 32 in 2016 to 52 in 2017. "Our prevention efforts with IV drug users have been incredibly successful," he says. "This is the first sign that maybe those efforts are starting to be eroded."Millions of people are alive today because of the global response to the AIDS epidemic, which has made ART available throughout the world. "But we will not end this epidemic just with pills," said Dr. Peter Piot, director of the London School of Hygiene and Tropical Medicine and an author of the Lancet study, at a July 16 press conference about the report. "We are concerned that the world will declare victory long before the fight is over. This commission report is a call to action to reinvigorate the fight against AIDS and to pay as much attention to prevention as to treatment."Susan Brink is a freelance writer who covers health and medicine. She is the author of The Fourth Trimester, and co-author of A Change of Heart. Copyright 2018 NPR. To see more, visit http://www.npr.org/.