Methods of communications and the nature of messaging are critically important in influencing public behavior. The COVID-19 pandemic has resulted in major disruptions to all aspects of life globally and has triggered multiple approaches of health messaging to the general public to communicate COVID-19 preventative measures. This study aimed to identify: (1) differences between age groups in the main avenues used by people to obtain COVID-19 related information; and (2) whether age and information sources were associated with correct interpretation of government messaging relating to how people understand or interpret the terms “self-isolation” and “social distancing.” An online survey was conducted in 2020. Participants were aged over 18 years and grouped into age group decades. Differences in sources of COVID-19 information were compared visually between age groups. Logistic regression was used to determine whether age and each of the various methods of communication of COVID-19 information were independently associated with correct response to the self-isolation, or the social distancing statements. There were 3,300 survey respondents 85% female; age sub-groups: 18–29 (7.4%); 30–39 (10.6%); 40–49 (17.6%); 50–59 (22.9%); 60–69 (25.9%); 70–79 (13.9%); and 80+ (1.7%). People accessed public health messaging information from a wide variety of sources that changed as they aged (e.g., older people were more likely to be exposed to COVID-19 information via television news programs and less likely via social media platforms). Age was frequently associated with whether the message key terms were interpreted correctly or incorrectly, but in some cases, it promoted more correct responses whereas in others, fewer correct responses. There was no difference between being exposed to COVID-19 information via mainstream media, compared with social media, or compared with Government sources of information, in terms of whether COVID-19 messages were interpreted correctly. In order to improve future public health messaging, there is a need for multiple avenues of communication to meet the needs and preferences across and within age groups. Further investigation is warranted into the clarity of the content and method of delivery of public health messages, to ensure optimal understanding of public health messages by vulnerable populations and across the community.

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).