More than 20,000 people of all backgrounds – scientists, activists, policy-makers, people living with HIV and others – will soon arrive in Washington DC for the XIX International AIDS Conference, to be held at the Walter E. Washington Convention Center from July 22 to 27, 2012. This is the first time in 22 years that the Conference has been held in the United States. Previous U.S. visa restrictions on people living with HIV have been lifted, opening the way for the conference to be held in the United States for the first time since 1990. These International AIDS Conferences have served as milestones in the history of the HIV/AIDS pandemic. The first was held in Atlanta, home of the Centers for Disease Control and Prevention (CDC), in 1985. Dr. Jim Curran, head of CDC’s HIV/AIDS activities in the early years, commented later on CDC’s pride in organizing this event, and that only 1,000 people came (compared with more than 20,000 expected in 2012). Each of the 17 conferences since has had its own character and influence, but several have stood out as visible markers along our journey in the pandemic.

The conference in Berlin in 1993 may represent the nadir in our collective mood about HIV/AIDS. Epidemiology described HIV/AIDS emerging in new areas of the world; East and parts of Central and West Africa were aflame with AIDS, political commitment was lacking, and research offered no solutions. Results of the Concorde trial, sponsored by the UK Medical Research Council, showed that zidovudine monotherapy had no long term benefit. I had the privilege of delivering a plenary lecture on HIV-associated tuberculosis, perhaps the first time that the association of these two major infections had been highlighted at a major meeting. Multidrug-resistant tuberculosis was causing a public health emergency in New York City, and the implications of HIV-associated tuberculosis globally were only just beginning to be perceived, with no end in sight.

The contrast between Berlin in 1993 and Vancouver in 1996 could not have been greater. The International AIDS Conference in Vancouver is synonymous with the introduction of highly active antiretroviral therapy (HAART), now just referred to as ART. Elegant studies and trials showed that viral load predicted disease progression, that combination ART lowered viral load, and that lowering of viral load resulted in improved survival of HIV-infected persons. Delegates were stunned by presentations of individual case histories of patients dying of AIDS who were rescued by ART, colorfully referred to as “the Lazarus effect”. I delivered a plenary presentation summarizing the clinical track of the conference and noted perhaps the only perplexing aspect of the proceedings, that the conference theme of “One World, One Hope” hardly applied to the real universe that in reality was one of “worlds apart”. The scientific advance of ART was restricted to high-income countries.

How different our world is today. When the International Conference on AIDS was held in Durban in 2000, who could have imagined the achievements we take for granted in 2012? Durban was important because it brought home to delegates and decision makers the reality of HIV/AIDS in Africa, most severe by then in the southern part of the continent. Durban unquestionably resulted in political pressures and processes that culminated in the creation of the Global Fund, PEPFAR, and the World Health Organization’s “3x5” initiative that aimed to have 3 million persons on ART by end-2005.

Who in Durban could have dreamt that within a decade almost 7 million people worldwide, most of them in sub-Saharan Africa, would have accessed ART? Just as importantly, the Durban conference heralded a golden age in global health that extended beyond HIV/AIDS and increased funding for malaria and neglected tropical diseases, and refocused attention to maternal and child health. In addition, necessary attention was brought to bear on the overall need to strengthen health systems.

And now to Washington in 2012. The economic situation in the world is discouraging, the Euro is wobbling, and there is an overall reticence to seeing the bright side of life. And yet, how much has been achieved! How much more can be done, even if resources are not growing as they were some years ago! Biomedical science has delivered extraordinary results in showing that HIV treatment is prevention, that prevention of mother-to-child transmission of HIV is possible everywhere (and including through breast feeding), and that male circumcision is a once-only, effective intervention with huge potential to prevent heterosexual acquisition of HIV in men. Behavioral science remains critically important, including guiding us on how to use these gifts more effectively.

The global community combating HIV/AIDS is positioned to make major advances against this epidemic, and we must not squander these opportunities. On behalf of CDC’s Center for Global Health, I want to welcome attendees of the XIX International AIDS conference to Washington.

Editor's Note: For information on the US Government's activities at the conference please visit USG@AIDS2012.