Diffusion of Innovations and HIV/AIDS JANE T. BERTRAND Bloomberg School of Public Health, Center for Communication Programs, Johns Hopkins University, Baltimore, Maryland, USA As the HIV/AIDS epidemic continues its relentless spread in many parts of the world, DOI provides a useful framework for analyzing the difficulties in achieving behavior change necessary to reduce HIV rates. The DOI concepts most relevant to this question include communication channels, the innovation-decision process, homo- phily, the attributes of the innovation, adopter categories, and opinion leaders. The preventive measures needed to halt the transmission of HIV constitute a ‘‘preventive innovation.’’ This article describes the attributes of this preventive innovation in terms of relative advantage, compatibility, complexity, trialability, and observability. It reviews studies that incorporated DOI into HIV/AIDS behavior change interventions, both in Western countries and in the developing world. Finally, it discusses possible reasons that the use of DOI has been fairly limited to date in HIV/AIDS prevention interventions in developing countries. The Challenge of HIV/AIDS HIV/AIDS has emerged as the greatest public health challenge in contemporary times. Given the lack of a vaccine or cure, behavior change is the only means to curb the further spread of this epidemic. In the vast majority of afflicted countries, the primary route of transmission is sexual. In response, many countries have instituted prevention efforts focused on the ABCs: abstinence, being faithful, and condom use. However, transmission by injection drug use has fueled the epidemic in other parts of the world, especially in the former Soviet Union and parts of Asia, including India and China. Needle exchange programs—to avoid the reuse of infected needles—are the response of choice to reduce the rate of infection in such countries. The epidemic initially spreads within subgroups of the population with high-risk behaviors, including commercial sex workers, migrant workers, truck drivers, and injection drug users. As HIV rates increase among these groups, the epidemic slowly progresses into the general population through sexual transmission from these groups to spouses, casual partners, and others. Indeed, once the HIV prevalence rate reaches five percent in a given country, the epidemic has generalized into the larger population and becomes much more difficult to contain. The HIV/AIDS epidemic continues to advance at a relentless pace. Over 40 million persons were infected with the HIV virus as of 2002; over 70% live in sub-Saharan Africa. Five African countries have an HIV prevalence of over 20%. The two demo- graphic giants in Asia—China and India—have relatively low prevalence rates, but the number of persons infected runs into the millions (UNAIDS, 2002). Eastern Europe and Central Asia have the fastest growing regional epidemics, with the number skyrocketing from an estimated 5000 cases in 1990 to 1 million in 2001 (Lamptey, Wigley, Carr, Colleymore, 2002). Journal of Health Communication, Volume 9: 113–121, 2004 Copyright # Taylor & Francis Inc. ISSN: 1081-0730 print/1087-0415 online DOI: 10.1080/10810730490271575 113