Effectiveness of tailored COVID-19 messages for vulnerable Australians: A study protocol.

Multiple approaches can be used to communicate public health messages through mass media. It is unclear which approaches are superior for meeting the needs of the general community along with vulnerable population subgroups. To compare different public health strategy communication approaches for influencing the COVID-safe behavioural intentions of both community and vulnerable population subgroups. This study will conduct three concurrent 'helix' randomised controlled trials with Latin square sequencing and factorial intervention allocation to assess the effectiveness of different communication strategies amongst the Australian general community and six subgroups that are considered vulnerable to contracting, transmitting or experiencing severe consequences of COVID-19 infection. Communication approaches being compared include: the format of communication (written versus video), who is providing information (general practitioner, politician, community-representative), what is said and how it is delivered (direct information provision versus conversational approach) and the visual content of video messaging (animation versus 'talking head'). Recruited participants will be randomly allocated to receive a specific combination of health messaging strategies using six different COVID-19 context areas. Outcomes will be assessed in a survey using behaviour intention questions, and questions surrounding level of agreement with feeling represented in the health messaging strategy. These trials will use a unique research approach to provide an experimental evidence base to help guide development of impactful and inclusive COVID-19 and related public health messaging. All three trials are registered with the Australian New Zealand Clinical Trials Registry (ANZCTR). Trial 1: Update and impact of Government recommendations about COVID-19 (coronavirus)-Stage 3, Trial 1, vulnerable subgroup populations (ACTRN12622000606785). Trial 2: Update and impact of Government recommendations about COVID-19 (coronavirus)-Stage 3, Trial 2, community group (ACTRN12622000605796). Trial 3: Update and impact of Government recommendations about COVID-19 (coronavirus)-Stage 3, Trial 3, What communication strategy is most effective for both vulnerable and community group populations? (ACTRN12622000617763).