Introduction

HPV vaccination is recommended for all children beginning at age nine for the prevention of several types of cancer. Many parents turn to social media for health information and Facebook is the most commonly used social media platform by parents of children aged 9-14. Interviews with pediatricians in our CPRIT project confirmed that parents shared concerns about HPV vaccination seen on Facebook and that providers were unsure about what was being shared via the social media site. The purpose of the study is to describe changes in HPV vaccine-related articles linked on Facebook before and during the COVID-19 pandemic.

Methods

HPV-related articles shared on Facebook (2019-2021) were collected using Buzzsumo, a web-crawling platform that indexes social engagement data. Articles were prioritized by engagement scores, defined as the total number of reactions, comments, and shares. Articles with engagement scores <1,000 were excluded. Articles were coded using both a priori and inductive coding of their evidence quality, persuasive strategies, and topic. Authors LAS, AM, EA coded an initial subset of 20 articles (Krippendorf’s alpha=0.811). The remaining articles were then independently coded in Atlas.ti Web.

Results

Included articles (n=138) had mainly positive valence towards the HPV vaccine (n=71;51%) with 36% (n=49) having negative valence, and 13% (n=18) having mixed valence (containing both pro- and anti-vaccine sentiment). This distribution differed by year, with a higher percentage of articles shared in 2021 having positive HPV vaccine messaging (72% in 2021 vs. 44% in both 2019 and 2020; chi-square p<0.01). Similarly, more articles were shared in 2019 having misinformation (50% in in 2019 vs 44% in 2020, 24% in 2021). Common sources of misinformation included linking HPV vaccines to: neurological side effects (“14-Year-Old Active Girl in Wisconsin Suffers Over 300 Seizures After Gardasil Vaccine,” 2019), death (“The verdict is now inescapable: Gardasil is killing girls,” 2020), and infertility (“It’s outrageous that a vaccine that robs women of the chance to have children…continues to be pushed on the masses,” 2019).

Prevalence of persuasive strategies (e.g., ideological assertions, fear appeals, promoting mistrust of institutions, and minimized severity of HPV-related outcomes) was greater in 2019 than in 2020 and 2021. For example, 52% of articles shared in 2019 promoted mistrust of institutions (“If you’re a pediatrician I would ask you to actually look at the science and not resort to appeals to authority because…all of those agencies and organizations have been corrupted by pharmaceutical industry money”) versus 20% of articles in 2020 and 15% in 2021.

Conversely, articles shared in later years were more likely to site scientific research (48% in 2019, 58% in 2020, 68% in 2021). For example, a 2021 article included the statement, “Cervical cancer rates fell by 87% in women who had HPV vaccine, U.K. study finds.”

Conclusion

Findings indicate less engagement with HPV-related articles posted on Facebook in 2021 than in years prior to COVID, and that shared articles tended to be more positive and included less misinformation, though almost a quarter of articles shared in 2021 still included misinformation. These findings are counter-intuitive, given the rise of vaccine misinformation circulating online in response to COVID. Still, our results can inform strategies for communicating with parents about the HPV vaccine, by anticipating the quality of information parents may have encountered online.