Background: Stigmatising attitudes and behaviours by others can have a range of negative effects for population groups and individual people affected by blood borne viruses. The reduction of stigma is a major goal within current Australian national health strategies, however, there is a lack of evidence regarding effective interventions to achieve this goal. Drawing on Allport's (1954) intergroup contact theory, this study aimed to evaluate the effectiveness of an online stigma reduction intervention implemented with the Australian public. ods: The study was conducted between February and May 2020. Australian adults recruited via Facebook advertising were randomly allocated to a control group (n= 316) or one of five intervention groups: people living with HIV (n= 320), people living with hepatitis C (n= 347), people living with hepatitis B (n= 333), people who inject drugs (n= 316), or sex workers (n= 296). Participants viewed a short video depicting lived experiences of their assigned group. Participants completed attitudinal measures about the group before and immediately after the video, and then at three-month follow-up. These measures related to overall attitudes towards the group, controllability of the stigmatised condition/behaviour, desire to maintain personal distance from the group, and opinions regarding treatment of the group in health care and public policy. Longitudinal changes in attitudes were analysed using a mixed effects regression model with maximum likelihood estimation. Results: Across each of the intervention groups, reductions in negative attitudes were found immediately after watching the videos on almost all outcome measures. By three-month follow-up, the HIV intervention group demonstrated long-term improvements in relation to personal distance compared to the control group, and the hepatitis B intervention group demonstrated long-term improvements in relation to attitudes and personal distance compared to the control group. Across intervention and control groups, long-term reductions in negative attitudes were found in relation to HIV controllability, hepatitis B controllability and opinions, hepatitis C controllability and opinions, and injecting drug use attitudes and opinions. Conclusion: Brief online videos depicting priority populations groups demonstrated positive results in terms of reducing some stigmatising attitudes towards those groups amongst members of the Australian public. Online contact interventions have the potential to be scaled up and rolled out across jurisdictions at national and international levels. These findings suggest that these interventions could be an effective way to contribute to the reduction of stigma and discrimination towards populations affected by blood borne viruses.
