Vaccine movements on social media : a visual and network analysis

Vaccines are considered one of the most effective public health interventions, but they have been subject to opposition since they were first proposed. Anti-vaccine activists disseminate and sensationalise objections to vaccinations through various channels, including the internet and social media outlets, such as Twitter. These means allow them to reach the public directly and potentially influence their intention to vaccinate. Twitter allows users to share short textual messages and images. Although, images have strong communicative power, there is a lack of research on the networks and actors sharing vaccine images. Moreover, there are no studies on the meaning and messages of these images. Therefore, this study aimed to investigate the dissemination, content, and meaning of anti- and pro-vaccine images in relation to their respective Twitter networks. A mixed methods approach was used to address the research aims, comprising social network analysis, visual content analysis, semiotics and visual social semiotics analyses. Anti-vaccine users re-shared images with each other; they provided support and strengthened their anti-vaccination beliefs. Some key actors, primarily activists and parents, influenced the information flow within the community. Anti-vaccine images claimed that vaccines are not safe, advocated against mandatory vaccinations and promoted vaccine conspiracy theories. They also provided alternative sources of information or pseudoscientific evidence supporting their messages while increasing distrust in traditional experts. The pro-vaccine users form loose connections that favour the dissemination of new vaccine information and networking. In this network, Non-Governmental Organisations (NGOs) and public health organisations influenced the dissemination of images, and the images mostly featured NGO campaigns and achievements in developing countries or promoted the flu vaccine in Western countries. In conclusion, anti- and pro-vaccine networks are insular and share different images in different ways; they use different visual communication strategies to reach their audiences. This resulted in a lack of a middle ground in visual communication of vaccines on Twitter. Addressing this gap could be an opportunity for future immunisation campaigns.