An Analysis of Pro-Vaccine and Anti-Vaccine Information on Social Networks and the Internet: Visual and Emotional Patterns

A high percentage of the population looks for health information on the internet, making their decisions accordingly. Interaction and discussion through social networks mean that the information received from search engines or certain persons is perceived as reliable without being more rigorously researched. This phenomenon is concerning in light of data showing a decrease in recent years in the vaccination of children against certain viruses, as well as the outbreak of diseases already eradicated. In that context, the objective of this research is to analyse the type of information on vaccines that exists on the internet: sources, references, themes, and tone (positive, negative, or neutral). In addition, the study analyses the flows of communication in the social networks Facebook and Twitter.

The methodology of Social Network Analysis (SNA) allows for the collection of data through web scraping techniques, enabling the monitoring and analysis of social networks and helping to identify those agents or nodes that centre around vaccines. Digital opinion leaders (DOLs) can be detected - being those who direct the conversation - as well as intrinsic characteristics such as the number of relationships established. In the same way, possible clusters can be detected that allow for the identification of groups within the network of nodes, based on different variables such as the topics of interest, or frames (specific diseases or vaccines). It is also possible to measure emotional weight and popularity of different groups within the network and between nodes. These implicit variables such as emotion and engagement can be analysed by neuro-communication techniques (eye-tracking, facial expression, and galvanic skin response, or GSR) that enable the registration of the psychological or automatic responses of the subjects against pro- and anti-vaccine information.

The following research questions (RQs) were raised:

• RQ1: What is the speech that is being broadcast by digital media, either from official sources, or from associations or individuals, about vaccines on the internet? More specifically: What are the most relevant issues, the sources and the tone, and treatment of the information?
• RQ2: What are the most relevant pro- and anti-vaccine tendencies on the internet and on Facebook?
• RQ3: What are the most relevant DOLs for and against vaccines on Twitter, and what communication flows do they disseminate?
• RQ4: Will a diachronic analysis of these information and communication flows of the last four years show evolutions or changes of significant trends?
• RQ5: Are there differences in the way of looking and structuring the information (visual gaze and heatmaps) between websites or information that fall in the pro- or anti-vaccine camps? In addition, will the gender variable cause differences in these visual patterns?

The article outlines the methodology in detail but, in brief, a descriptive analysis was developed for publications about vaccines on the sites (websites, blogs, digital press) and social networks Facebook and Twitter, in the months of April 2015, 2016, 2017, and 2018. For the analysis of the implicit variables carried out by means of neuro-communication techniques, a sample of 18 subjects voluntary participated, chosen randomly among students and administration and services staff of the Universidad Complutense de Madrid (Spain). The following variables were evaluated: emotion, attention, visual path, and engagement. The subjects were exposed to two screenshots of two websites with opposite positions towards vaccines (Redacción médica, pro-vaccine, and Buscando la verdad, anti-vaccine). Both images show a web portal with an upper header, a news with headline and image, and a module in the shape of a banner for the latest news.

In brief, the research found that the flow of communication was not constant, both in the press and on websites (376 news items in 2015, 74 in 2016, 69 in 2017 and, 268 in 2018). The tone used by the media in websites and digital press towards vaccines usually trends towards being neutral, followed by pro-vaccine. The number of media platforms talking about vaccines has diversified, making it difficult for those reporting about vaccines to be specialists on the subject. In fact, 80% came from non-professional sources (only 17% were written by a journalist and 3% by a health specialist). With this increase in information about vaccines, there is a lack of reference sites in relation to information sources.

With regard to social networks, anti-vaccine Facebook messages and groups were identified, and a mapping of influencers is presented. The analysis of the DOLs shows two common denominators: (i) the ability to combine different digital platforms, such as a main web page of a more informative nature with frequent publications in social networks; and (ii) the importance of constancy in publishing and activity through time. Analysis of the temporal evolution (years 2015 to 2018) of communicative flows showed that anti-vaccine posts decreased. For instance, in 2015 most Facebook groups in Spanish focused on public health were anti-vaccine, while in 2018 a greater diversity was found: 60% against, 30% in favour, and 10% neutral. While on a general level, there is a greater popularity of pro-vaccine profiles, this trend varies in the case of Spanish pages, the most popular being anti-vaccines, especially the page of Miguel Jara, which has maintained popularity over time. Social media spaces lack the presence of specialists and tend to have a negative or fearful tone towards vaccines, even if they are "neutral".

With regard to RQ5, the headline of the anti-vaccine page attracted more attention from the subjects than did the pro-vaccine one. However, emotional responses and engagement did not show differences between pro-vaccine and anti-vaccine websites. This deviates from expectations, given that the original hypothesis held that anti-vaccines use messages that mobilise "limbic resonances" rather than more objective and less emotional messages of the pro-vaccine information sources. The results raise a new perspective, where persuasion would not occur as much through the emotional route but over cognitive stimuli. This way, people with determined prior beliefs - take, for example, beliefs in conspiracy theories - would use the representational heuristic, thus avoiding full reasoning about events that involve uncertainty, probability, and risk. Gender differences appeared in the visual exploration of information sources and in the provoked emotion responses (GSR and facial expression). In pro-vaccine pages, women looked at the headline first, while men looked at the photograph. According to the researchers, more empirical work on gender differences in the way of looking at and structuring information is needed to understand its possible effects on the cognitive processing of individuals.

The researchers conclude with the contention that these data could be useful for the design of future communication campaigns accompanying vaccine interventions, health education, and programmes of primary prevention in the field of public health.

Click here to read the 17-page article in Spanish (PDF).