HIV/AIDS surveillance and prevention studies in Japan: summary and recommendations.

Japan is considered to have a low prevalence of HIV/AIDS, with a cumulative number of 2,556 AIDS cases and 5,140 HIV cases reported by the end of 2002. However, the recent trend of HIV cases shows a substantial increase, particularly among men who have sex with men and youth/young adults. The epidemiology of HIV/AIDS cases in Japan and a summary of current HIV prevention studies are presented based on surveillance data, research papers, and the Japanese government's annual reports on HIV behavioral and intervention studies of MSM, youths, and Japanese nationals who visit or are temporarily staying in the United States or Thailand. Recommendations and suggestions are presented for future HIV prevention research and structural changes in the Japanese government system, which funds HIV/AIDS care and prevention studies.