Evaluating the World Health Organization's health promotion strategies: Sentiments, health beliefs, and the COVID-19 pandemic.

Based on the Health Belief Model (HBM), this study examined what messages about COVID-19 were presented on the World Health Organization (WHO)'s Facebook posts, and evaluated WHO's health promotion strategies by examining the public engagement and sentiment stimulated by different health promotion constructs. One issue with previous studies on HBM and social networking sites is that many researchers considered positive "online engagements" as evidence of "effective health promotion". However, online engagement measures such as shares and comments cannot reflect the sentiment's valence. Another limitation in previous studies is that they often failed to differentiate between sentiments towards health measures and sentiments towards the disease. We utilized Facebook's emojis to explore the public's distinct sentiments towards the WHO's COVID-19-related health measures and sentiments towards COVID-19. We used content analysis to examine the all the COVID-19-related Facebook posts published by the WHO in 2020, the first year of the pandemic when the COVID-19 vaccines were not generally available to the public. In general, the use of HBM constructs was successful in capturing users' attention and generating engagement. However, regarding the effect of the use of HBM constructs on the beliefs in COVID-19-related health measures, the results were complex. The mentioning of the beliefs about a disease (perceived susceptibility and severity) tend to induce people's negative sentiments. The mentioning of ways to increase self-efficacy and cues to actions significantly reduced people's online engagements and sentiment (either positive or negative). Benefits only stimulated users' negative reactions while barriers could not stimulate any reactions. Video and text posts generally attracted more Facebook engagement than image and text posts, while text-only posts generally received the least Facebook engagement. We demonstrated that certain health promotion strategies can backfire and even induce negative reactions. Policymakers should be alert to this phenomenon when mentioning certain constructs during health promotions.