Estimating the influence of Twitter on pre-exposure prophylaxis use and HIV testing as a function of rates of men who have sex with men in the United States

Objective(s):Acceptance of pre-exposure prophylaxis (PrEP) and testing for HIV is likely to vary as a function of the norms and communications within a geographic area. This study examined associations involving county tweets, in person communications, and HIV prevention and testing in regions with higher (vs. lower) estimated rates of men who have sex with men (MSM).Design and Methods:Ecological analyses examined (a) tweets about HIV (i.e. tweet rates per 100 000 county population and topic probabilities in 1959 US counties); (b) individual-level survey data about HIV prevention and testing and communications about PrEP and HIV (N = 30 675 participants); and (c) estimated county-level MSM rates (per 1 000 adult men).Results:In counties with higher rates of MSM, tweet rates were directly associated with PrEP use and HIV testing (rs = .06, BF10 > 10). Topics correlated with PrEP use (rs = -0.06 to 0.07, BF10 > 10) and HIV testing (rs = -0.05 to 0.05, BF10 > 10). Mediation analyses showed that hearing about and discussing PrEP mediated the relations between tweet rates and PrEP use (bi∗ = 0.01-0.05, BF10 > 100) and between topics and PrEP use (bi∗ = -0.04- 0.05, BF10 > 10). Moreover, hearing about PrEP was associated with PrEP use, which was in turn associated with tweet rates (bi∗ = 0.01, BF10 > 100) and topics (bi∗ = -0.03 - 0.01, BF10 > 10).Conclusions:Rates of MSM appear to lead to HIV tweets in a region, in person communications about PrEP, and, ultimately, actual PrEP use. Also, as more men hear about PrEP, they may use PrEP more and may tweet about HIV.