Despite ongoing HIV prevention efforts since the early days of the HIV epidemic, HIV transmission has remained steady, with an estimated 50,000 new HIV cases every year. The metropolitan Washington, DC area has a high proportion of inhabitants (2.4%) with HIV infection in 2011. There are drastic differences in affected groups, with 75% of new HIV diagnoses being amongst African Americans. When considered by sexual categories, the hightest proportion of new diagnoses (37.5%) was seen among men who have sex with men, while 31.4% of new infections were attirbuted to heterosexual transmisison.
Public health efforts to prevent HIV transmission are tailored to the local epidemic, with specific interventions geared to specifc risk groups. HIV reporting captures reported risk factors for HIV, but the risk for HIV is heavily influenced not only by individuals' behavior, but also by social and sexual contacts. Risk of transmission is not uniform - for example, 'high risk' sexual activity may not result in HIV transmission if all involved parties are HIV- and are not in the 'window period' during which identification of HIV infection requires special testing. However, high risk behavior within a group with a high proportion of HIV+ individuals is more likely to resul in a transmission event.
Further characterizing HIV transmission networks to identify large HIV transmission clusters by studying the virus will increase our understanding of the local HIV epidemic, and could potentially guide HIV prevention strategies. This project aims to study the patters of HIV transmission and transmitted drug resistance in Washington, DC. Identification of large HIV clusters can inform public health efforts for targeted interventions to interrupt ongoing HIV transmisison using newer HIV treatment and prevention methods, including treatment as prevention of HIV+ individuals and the use of pre-exposure prophylaxix (PrEP) among HIV- individuals. Information about primary drug resistance within the District of Columbia is needed to guide regional clinical practice and judicious use of antiretroviral therapy regimens.