Sample composition and HIV prevention indicator differences using physical vs. virtual venue recruitment of men who have sex with men in San Francisco.

During the COVID-19 pandemic, the sampling method for the National HIV Behavioral Surveillance (NHBS) in San Francisco changed from physical venue time-location sampling (TLS) to online or virtual venue TLS for men who have sex with men (MSM). We present differences in the samples of MSM recruited using physical venue TLS in 2017 and virtual venue TLS in 2021. We further assess changes in preventive and risk behaviors from 2017 to 2021 after controlling for differences in the sample compositions with multivariable Poisson models using GLM with robust standard errors. Both sampling methods exceeded their targeted sample size of 500 (physical venue TLS n=502, virtual venue TLS n=505). Compared to physical venue TLS, the virtual venue TLS sample had fewer persons experiencing homelessness and incarceration, and more persons with health insurance and post-graduate degrees. After adjusting for these differences and age, race, and employment status, PrEP use increased from 2017 to 2021. The use of several non-injection drugs also increased, namely marijuana, poppers, ketamine, psilocybin, and LSD. We found virtual venue recruitment of MSM to be a viable approach for tracking trends in HIV-related behaviors, with notable appeal given possible future pandemic lockdowns of physical venues and changing socialization patterns.