UCSF

The focus of this dissertation is estimating the distribution of behavioral patterns prior to HIV infection---including behaviors such as serosorting and use of pre-exposure prophylaxis---among newly HIV-infected San Francisco MSM. These quantities have been surprisingly elusive, particularly for the complex behavioral patterns considered in our studies. Though officials and researchers have hypothesized---and sometimes assumed---that HIV infection primarily occurs among high-risk MSM, it is alternatively possible that infection mostly occurs among relatively low-risk MSM, since there are more low-risk MSM in San Francisco than high-risk MSM. Understanding of these quantities could help identify what groups of San Francisco MSM should be reached by HIV prevention.

The 2nd chapter of this dissertation examines per-act risks for HIV transmission, which are a crucial basis for a mathematical model we developed and used to estimate the distribution of prior behavioral patterns among newly HIV-infected San Francisco MSM. The 3rd chapter presents the model and its findings. Finally, the 4th chapter examines possible barriers to intervening on the risk group identified via the model.