Characterizing HPV Vaccine Sentiments and Content on Instagram.

With its growing popularity, inclusion of image and text, and user-friendly interface, Instagram is uniquely positioned for exploring health behaviors and sources and types of informational exposure related to the human papillomavirus (HPV) vaccine. To characterize public Instagram posts about the HPV vaccine and quantify the impact of sentiment and context on engagement via likes. Using Netlytic, 3,378 publicly available English-language posts were collected using the search terms "#HPV," "#HPVVaccine," and "#Gardasil." We randomly selected 1,200 posts to content analyze. Our final analytic sample included 360 posts after excluding posts whose links were no longer active ( = 221) or that were not relevant ( = 619). A higher proportion of posts were pro-vaccine (55.8%) than anti-vaccine (42.2%). Pro-HPV vaccination posts were liked significantly less than anti-vaccination posts (24 vs. 86 likes; < .001). More posts contained actionable information/resources (63.9%) than personal narrative elements (36.1%). Less than one in three posts (30.0%) came from health-related sources. Pro-vaccine posts were more prevalent on Instagram, and anti-vaccine posts had higher engagement and typically included misleading information about the HPV vaccine. Personal narratives skewed toward anti-vaccine sentiments and most were produced by individual users. Pro-vaccine narratives portrayed individuals who received the vaccine, but provided limited details on vaccine experiences, starkly contrasting with the depth of details in anti-vaccine personal narrative posts. On Instagram, individuals and organizations have an opportunity to promote HPV vaccination by continuing to provide informational resources in addition to creating more narrative-style posts.