Impact of “absolute” versus “relative” HIV risk communication on pre-exposure prophylaxis interest in Canada: a randomized survey

The way human immunodeficiency virus (HIV) acquisition risk is communicated can shape individuals' perceptions and their interest in using pre-exposure prophylaxis (PrEP). This study examined two risk communication strategies among non-PrEP-using gay, bisexual, and other men who have sex with men (GBM) in Canada. In 2022, adult GBMs in Ontario and British Columbia completed an online survey and were randomly assigned to receive HIV risk messages tailored to their risk assessment scores. Messages were framed in either absolute terms ("Your risk is XX%") or relative terms ("Your risk is XX times that of other GBM"). Participants compared this with their self-rated HIV risk and indicated whether it increased their interest in PrEP. Logistic regression models were applied to analyze the data. Among 461 participants, 64.2% perceived themselves as low risk and 51.0% met clinical indications for PrEP. Of 428 participants, 56.9% in the "absolute" group versus 43.1% in the "relative" group reported increased PrEP interest (difference=13.8%, p=0.071). In multivariable analyses, absolute risk message framing was associated with higher, though non-significant, PrEP interest in the model adjusted for clinical indication (AOR:1.74, 95%CI:0.86-3.59) and in the model adjusted for prior PrEP use (AOR:1.49, 95%CI:0.95-2.35). These findings suggest that individualized risk framing in absolute terms may encourage PrEP interest, but addressing PrEP stigma and structural barriers such as cost remains essential to expand PrEP use.