The prevention of HIV in the United States is in a transformational era. In just a decade since the first finding of efficacy for daily oral PrEP, there has been a proliferation of new PrEP agents, including long-acting injectable PrEP, and regimens, including "event-driven" (also called "on demand" or 2-1-1 dosing) PrEP. There has also been new knowledge about the impact of antiretrovirals (ARVs) on the treatment of HIV, and an emergent understanding that people living with HIV who take ARVs and maintain a suppressed viral load are incapable of transmitting HIV to their sexual partners. In this context, the idea of "protected" sex - which historically meant sex protected by condoms - has become much more complex.6 Men who have sex with men (MSM) and others at risk for acquiring HIV are now making decisions about how to reduce their risks of HIV infection in a world where there are many more options to reduce risks of infection, and where those options also interact with the HIV status and viral suppression status of their sex partners. Understanding men's preferences for prevention products and strategies and what choices are being made by men with varying risk profiles is critical to public health responses and programs to reduce new HIV infections.

MSM are the most highly impacted groups by HIV in the US, with transmission largely driven by high per-act risk MSM. Among MSM, Black/African American (Black) and Hispanic/Latino (Hispanic) men experience nested health inequities: in 2020 Black men comprised 13% of US men and 38% of MSM diagnosed with HIV, and Hispanic men comprised 19% of US men and 33% of MSM diagnosed with HIV. Uptake of daily oral PrEP use by Black and Hispanic MSM has been slow and the extent of PrEP use among these men has not been equitable in light of their disproportionate impact in the HIV epidemic. Similarly, HIV incidence is concentrated in young MSM of all races. Thus, research to increase our understanding of men's awareness of, attitudes for and use of new prevention options must prioritize the equitable engagement of Black, Hispanic, and younger MSM.

The next 5 years will be a period of rapid changes in the fallout of new PrEP options and will likely see the introduction of new PrEP modalities (e.g., long-acting injectable PrEP, lower frequency oral dosing). Understanding the choices and patterns of PrEP use and the reasons and motivations for those choices among geographically, racially, and ethnically diverse groups of MSM will be a critical part of monitoring the public health response and informing public health programs and messaging. Ideally, public health messaging will be driven by up-to-date information about the perceptions, preferences, and practices of those MSM at the highest risk of HIV acquisition. During this era of rapid change in the available PrEP options, it is critical to have a robust system of real-time monitoring for PrEP preferences, what prevention options men are choosing, and what messages might be most impactful to support the appropriate uptake of PrEP and persistence on PrEP. Because the investigators expect numerous changes in the availability of PrEP products and treatment guidelines, it is also critical to be able to process and interpret these data in a timely way, to best support nimble decisions in prevention messaging and programs in response to a changing landscape of prevention options