David Celentano, ScD '77, MHS '75, is Professor and Charles Armstrong Chair of the Department of Epidemiology, with joint appointments in International Health, Health, Society and Behavior and Medicine (School of Medicine). His research integrates behavioral science theory and research with epidemiology methods in the study of behavioral and social epidemiology. While originally trained in a chronic disease paradigm (alcoholism and cancer control), he began his research in HIV/AIDS and STDs in the early 1980s. He has worked on some of the major cohort studies (ALIVE, MACS) in HIV epidemiology, as well as conducted intervention research in the USA for heterosexual men and women, injection drug users, and young men who have sex with men. He turned to international research in 1990, when he began a long-term collaboration with Chiang Mai University in northern Thailand. He has worked on and directed numerous HIV/AIDS and STD epidemiological investigations and preventive interventions. He and his collaborators have demonstrated that a behavioral intervention with young military conscripts lead to a 7-fold reduction in incident STDs and halved the HIV incidence rate. In addition, the role of STDs and alcohol use on HIV acquisition has been documented. More recently, his group has conducted a prospective study of hormonal contraception in relation to HIV seroconversion, a study with significant family planning policy and health implications. He recently completed four NIH-supported studies in Thailand, focusing on interventions to influence the association between opiate use, methamphetamine use, and other drugs on HIV. The focus of these interventions was to harness indigenous peer networks for risk reduction.He was the Thailand PI of Project Accept/HPTN 043, which showed the strong influence of community mobilization, HIV counseling and testing at the village level with post-test support services reduced behavioral risk and increased HCT to 72% of at-risk villagers in three years. Other work addressed the use of antiretroviral treatment as HIV prevention (HPTN 052) that demonstrated a >90% reduction in HIV transmission and opioid substitution therapy as HIV prevention (NPTN 058) for persons who inject drugs. On-going research includes a community-randomized trial of methods to link men who have sex with men with needed health and psychological health services in India. He is a mentor to several DrPH students from Abu Dhabi, UAE and is doing public health practice in the State of Qatar with Ministry of Health funding.