Abstract PR10: Examining the #HPV vaccine on Instagram: An analysis of post context, imagery, and sentiment
Authors: Kearney Matthew , Selvan Preethi , Hauer Michael , Leader Amy , Massey Philip 
Published: June 2022

Abstract
Introduction: We aimed to characterize publicly available Instagram posts about the human papillomavirus (HPV) vaccine and the impact of sentiment and context on post popularity via likes.
Methods: Using Netlytic, 3,378 publicly available English-language posts were collected using the search terms “HPV,” “HPVVaccine,” and “Gardasil.” A sub-sample of posts were randomly selected (n=288) and qualitatively coded to categorize aspects of a relevant post’s image, caption text, user, sentiment, and vaccine information. Coding and assessment of inter-rater reliability were facilitated by NVivo 12 (QSR Software), and discrepancies were resolved through group consensus. Descriptive and bivariate statistical analyses were conducted using StataIC 15.
Results: Four out of ten posts (n=114; 39.7%) depicted age-eligible individuals for the HPV vaccine. Girls were shown more than boys (26.6% versus 8.7%). One in four posts depicted the HPV vaccine (e.g., needle injection; n=70; 24.4%). Few posts included parents/caregiver figures (n=13; 4.6%) or health care professionals (n=41; 14.4%). User type was split evenly between individual and nonindividual users (51.2% individual versus 48.8% nonindividual). A majority of posts contained actionable information/resources (63.4%), compared to featuring personal narrative elements (36.62%). Posts were equally likely to be positive (50.9%) versus negative (46.0 %). Images showing males or females separately were more negative than positive, but males and females shown together were overwhelming positive (p = .0017). Nonindividual users posted positively significantly more than individual users (p &lt; .001). Personal narratives were significantly more negative than informational posts (p &lt; .001). The prototypic “most popular” post would have been antivaccine, shown a vaccine and a vaccine-eligible male, featured a combination of text and imagery, and included personal narrative elements. The average number of likes was 54 (SD = 143). Provaccination posts were liked significantly less than antivaccination posts (21 versus 93 likes; p = .0419).
Conclusion: In the era of “fake news,” HPV vaccination on Instagram is a topic characterized by emotionally charged expressions of personal beliefs, personal narratives, information, and misinformation. Personal narratives about HPV vaccination skewed towards antivaccine sentiment and were produced more often by individual users. Provaccine narratives tended to show individuals who had recently received the vaccine, but rarely provided long-term details about their experience with vaccination, starkly contrasting with the depth and scope of details included in antivaccine personal narrative posts. Unlike other social media, Instagram posts were more evenly divided between pro- and antivaccine expressions, creating an opportunity for provaccine individuals and organizations to promote HPV vaccination through the use of effective content, such as narrative-style posts.
Citation Format: Matthew Kearney, Preethi Selvan, Michael Hauer, Amy Leader, Philip Massey. Examining the #HPV vaccine on Instagram: An analysis of post context, imagery, and sentiment [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr PR10.