The effect of Abstinence, Being faithful to one partner, and Condom use (ABC) messages on HIV infection among youth in UgandaByJohn Paul EkwaruDoctor of Philosophy in EpidemiologyUniversity of California, BerkeleyProfessor Arthur Reingold, ChairUganda has suffered a devastating epidemic of HIV/AIDS for the last two and a half decades, with an estimated 2.6 million people becoming infected by 2005, half of whom had died by the end of that year. In 2009 an estimated 1.2 million people were living with HIV/AIDS in Uganda, including 120,000 who became infected in 2009. A campaign for abstinence from sex, being faithful to one sexual partner and condom use (ABC) became a pillar of HIV/AIDS prevention efforts in Uganda. Though there are indications that this intervention played a role in reducing the prevalence of HIV in Uganda, there are no data with which to estimate the impact of this intervention. It is important to determine the effect of this intervention, particularly among youth, who are thought to be a window of hope for changing the course of the HIV pandemic. There is also a need to explore the relationship between stigma and risky sexual behavior. While it has been shown that stigma affects uptake of voluntary counseling and testing (VCT), it is possible that stigma may also have effects on sexual behavior. While reluctance to take up VCT may be due to fear of being stigmatized when found to be HIV positive, it is also possible that fear of being stigmatized may lead to safer sexual behavior. Exploring the relationship between HIV/AIDS-related stigma and sexual behavior requires a valid measure of HIV/AIDS related stigma, but there is currently no such instrument that has been validated for use among youth in Uganda.The aims of this dissertation were to estimate the effects of the abstinence, being faithful, and condom use messages (ABC) on risky sexual behavior and HIV infection among youth in Uganda and to develop an instrument for measuring HIV/AIDS-related stigma among youth in Uganda.Chapter 1 presents an overview of HIV/AIDS and prevention efforts in Uganda.Chapter 2 utilizes data from the Uganda National HIV sero and behavioral Survey of 2004/2005 to estimate the effect of the ABC messages on the prevalence of HIV infection among youth in Uganda.Chapter 3 also utilizes data from the Uganda National HIV zero and behavioral Survey of 2004/2005 to estimate the effect of the ABC messages on risky sexual behavior among youth in Uganda.Chapter 4 presents a report on the development process for and psychometric properties of an instrument that was developed to measure HIV/AIDS-related stigma among youth in Uganda. Chapter 5 presents a summary of study findings, conclusions and implications for public health and future research