LAUSR

Over the past few decades the world has witnessed the evolution of the HIV epidemic, from the initial reports on AIDS in 1982, through its rapid expansion with devastating global impacts, through the most recent period during which AIDS-related mortality and new infections among children have declined faster than new infections among adults [1]. At the SDG meeting in September 2015 the global community committed to ending the AIDS epidemic by 2030 [2], and at the High Level Meeting on HIV and AIDS in June 2016 this same community aimed to reduce new infections to less than 500,000 by 2020 [3]. Modelling analyses underlie these commitments, demonstrating that major reductions in HIV incidence and AIDS-related deaths by 80–90% are possible by 2030 [4]. The global community has taken a strong commitment to build on the past momentum and realise these goals. As we look ahead, many lessons are to be learned from the past AIDS response. Some of the major contributions over the past decade and a half of leadership, advocacy, financing, country ownership, partnerships, civil society, rights and social justice, science and data have already been highlighted recently [5]. Across this time frame, the AIDS response has grown in maturity and sophistication, built on robust collaboration and singular purpose. The science of HIV has grown and dramatically influenced our understanding of the impact of available interventions, and epidemiological and monitoring data have been a foundation of the entire response to the epidemic. Data on the changing epidemiology have been important to shape and target programmes to where HIV transmission is most intense and to leave nobody behind [6]. Programmatic data have served the ongoing management of specific responses and allowed for adaptation and realignment of the programmatic effort. In the aggregate, data have been instrumental to the progress, accountability and success of the entire global AIDS response. The HIV response has been able to translate commitments into funding, programmes and results. The current supplement aims to bring together papers on the approaches, indicators and data systems that have been used to monitor the AIDS response to date. The first two papers describe how UNAIDS (including WHO, UNICEF and other co-sponsors), and The Global Fund to fight AIDS, Tuberculosis and Malaria have defined indicators and designed data collection systems and reporting mechanisms to ensure accountability within their respective results frameworks and distil lessons for future monitoring [7, 8]. A second set of papers takes a country perspective on monitoring the AIDS response, covering Nigeria, Ukraine, and the United Kingdom [9–11]. Countries with different types of epidemics and different health systems have rightfully adapted the global frameworks to their local situation, providing a tailored system consistent with their epidemics. The ability to translate global commitments and targets into country accountability has been a critical part of the AIDS response. Topic-specific papers describe the monitoring of the care CASCADE, of programmes for the prevention of mother-to-child transmission, and of programmes for key & Peter D. Ghys [email protected]