Investigating the effect of undetectable = untransmittable message frames on HIV stigma: an online experiment.

People living with HIV who maintain an undetectable viral load by adhering to antiretroviral therapy cannot transmit the virus to others. The present pre-registered study sought to investigate whether messages about this fact have the potential to decrease HIV stigma, drawing on the framework of the Elaboration Likelihood Model to test variations in message framing, and measuring issue involvement as a covariate. Participants (N = 314) were randomised to one of three conditions: control message, opinion-based message, and evidence-based message. Using a between-subjects one-way ANOVA, it was found that there was no significant effect of the U = U message on perceived risk or perceived accuracy of the message. When controlling for issue involvement, operationalised as the extent to which participants felt that they can empathise with people living with HIV, participants who received the evidence-based U = U message reported lower stigmatising attitudes than those who received the opinion-based message. These adjusted results suggested that evidence-based framing was more effective than opinion-based framing and an unrelated control message.