Facebook's Shared Articles on HPV Vaccination: Analysis of Persuasive Strategies

"Knowledge about the range of persuasive appeals that parents encounter online will better prepare physicians and health communicators to anticipate and address parental concerns about HPV vaccination."

Because human papillomavirus (HPV) vaccination is recommended at age 11 or 12, parents and guardians are often the primary decision-makers regarding HPV vaccination. Parents considering vaccines for their children often turn to the internet and social media for information. In the United States (US), Facebook is the most frequently used social media platform among parents whose children are ages 9-14. However, information that parents consume via Facebook may be susceptible to inaccuracy. This study analysed the persuasive strategies used in HPV vaccine-relevant information in articles shared on Facebook between 2019 and 2021 that discuss the HPV vaccine.

Existing research about public online discourse about the HPV vaccine has noted the use of several persuasive strategies. For example, the following arguments and tactics have been documented in online anti-HPV vaccine discourse: downplaying individual susceptibility to HPV; appealing to civil liberties in opposition to vaccine mandates; using personal narratives as a form of evidence; referencing doctors or other medical authority figures as a form of evidence; appealing to mistrust of Western countries (specific to platforms in Eastern countries); and appealing to mistrust of institutions, such as government or pharmaceutical companies. Conversely, online public discourse portraying the HPV vaccine positively may also contain persuasive strategies, such as referencing peer-reviewed publications and government health sites or telling personal narratives.

The Elaboration Likelihood Model (ELM), a cognitive processing theory, was selected to guide the study because its integrative framework encompasses a wide range of research findings from persuasion research. ELM describes message elements that enhance persuasion when message consumers carefully attend to the content of persuasive messages (high elaboration), or when message consumers quickly process messages without deep thinking (low elaboration). During high elaboration, the presentation of evidence and argument quality are key drivers of persuasion. ELM also outlines several message elements, known as heuristic cues, that may bolster persuasion when message consumers are engaging in low elaboration.

Using Buzzsumo.com, the researchers collected 138 articles shared on Facebook between 2019 and 2021 with the highest "engagement scores", or total number of reactions, comments, and shares. A content analysis methodology revealed that 72 articles had a positive valence toward the HPV vaccine, 48 had a negative valence, and 18 were mixed-valence or neutral.

Pro-vaccine articles primarily originated from national and local news sources, and they presented a variety of evidence types in support of benefits of HPV vaccination, including: statistics (n = 68 articles), public health authority figures (n = 63), links to other sources (n = 57), scientific research (n = 54), and scientific authority figures (n = 36). Persuasive tactics were not frequent among pro-vaccine articles. When articles included hyperlinks to other sources, they were often presented to bolster the credibility of claims or statements of fact presented in the article by providing a link to a credible source, such as a government organisation or scientific research. The primary topic of discourse involved cancer prevention, which typically invoked a "gain" frame by describing cancer prevention as a key benefit of HPV vaccination. When describing the vaccine and HPV, positive-valence articles also often included information about sexual transmission of HPV.

Anti-vaccine articles combined presentation of evidence with persuasive arguments and strategies, such as mistrust of institutions, fear appeals, ideological appeals, presenting a high number of arguments or detail (at a glance conveying the sense that the article is written by someone with in-depth knowledge and enhancing the perceived credibility of the source), and minimising the severity of HPV. Personal narratives described stories about side-effects someone experienced after receiving the HPV vaccine. Stories often emphasised life-altering side-effects and often accompanied information about lawsuits filed against pharmaceutical companies for damages. Anti-vaccine articles strategically used hyperlinks to create the appearance of ample evidence in support of vaccine harms or inefficacy, embedding hyperlinks throughout many of the article's claims without providing context about the hyperlinks' destinations. Cancer prevention discourse within these articles repeated misinformation claims that the HPV vaccine causes cervical cancer, rather than preventing it. Discourse about the sexual transmission of HPV emphasised the idea that it is inappropriate to vaccinate children for a sexually transmitted disease. Three sources were responsible for producing 62.5% of all anti-vaccine articles in the dataset. ("Future research should continue to explore strategies for targeting the spread of misinformation originating from a small number of unmoderated websites, that is then shared on social media platforms.")

Mixed-valence or neutral articles mixed cancer prevention discourse with ideological appeals about protecting parental rights, and they were mostly produced by local news outlets. It seems likely that local journalists, who perceive creating a community forum as an important function of local news, would be more likely to seek out and report "both sides" of the debate about HPV vaccination. Mixed-valence/neutral articles primarily focused on proposed legislation that, if passed, would require HPV vaccination for school attendance.

Per the researchers, paediatricians and health communicators can use the results from this study to anticipate the concerns or perspectives that vaccine-hesitant parents may have encountered online. Recommendations include:

• Given the prevalence of ideological appeals warning about suppression of questions or concerns about the HPV vaccine in the dataset, it may be prudent to thoughtfully hear out and address hesitant parents' concerns and questions.
• Paediatricians and health communicators should be prepared to address concerns about lawsuits claiming vaccine damages and about the reliability of existing evidence about the vaccine's safety. Pharmaceutical companies and government-associated public health organizations were sometimes treated with suspicion, but anti-vaccine articles usually presented evidence from scientific research, scientific authority figures, and medical authority figures as trustworthy. It may be useful to highlight these information sources in patient-provider conversations and in educational literature.
• The lack of persuasive tactics and arguments present in pro-vaccine articles highlights a missed opportunity that health communicators should address by integrating persuasive appeals into HPV vaccine messaging.