Analysis of the AntiVaccine Movement in Twitter. A perspective from Latin America

We are in the presence of a very worrying social phenomenon that, especially in recent years − and even more so in the wake of the COVID-19 pandemic − has become highly relevant: science denialism, that is ‘the rejection of the scientific consensus, often in favor of a radical and controversial point of view’ (Scudellari, 2010). The existence of doubts in society about the efficacy and safety of vaccines (Mallapaty, 2021) and the anthropogenic contribution to climate change (Björnberg et al., 2017; Strozewski, 2021) are examples of the gap between what the scientific community considers reasonably corroborated or refuted, on the one hand, and what outside the scientific community is seen as ‘controversial’ on the other.

Among science denialism in general, the anti-vaccine trend poses a serious threat to public health since it hinders the achievement of herd immunity. According to the Strategic Advisory Group of Experts on Immunization (SAGE), the term ‘vaccine hesitancy’ refers to ‘delay in acceptance or refusal of vaccination despite availability of vaccination services’ (MacDonald, 2015). This is such an impending issue that the World Health Organization (WHO) has identified it as one of the top threats to global health (WHO, 2019). The reasons behind vaccine hesitancy are complex, but they can be analyzed in terms of what is called the ‘epidemiologic triad’: environmental factors (such as health policies and messages in the media), agent factors (perception of vaccine safety and effectiveness, etc.) and host factors (knowledge and previous experience, among others) (Kumar et al., 2016; Sallam, 2021).

An extensive review by Sallam (2021) found that the lowest vaccine acceptance rates in 2020 were in Kuwait (23.6%), Jordan (28.4%) and Italy (53.7). According to another study by Steinert et al. (2022) the vaccine hesitancy in European countries ranged from 6.4% of adults in Spain to 61.8% in Bulgaria (Steinert et al., 2022). In general, the phenomenon of COVID-19 vaccine hesitancy was found to be more pronounced in the Middle East/North Africa, Europe and Central Asia, and Western/Central Africa (Sallam et al., 2022).

Latin America has current vaccine acceptance rates that are, on average, greater than those in Europe or the United States, typically around 70% (Sallam et al., 2022; Urrunaga-Pastor et al., 2021). Despite this and though vaccination coverage is higher than in other regions, it is still lower than what the Pan American Health Organization (PAHO) sets as an ideal (Guzman-Holst et al., 2020).

To counteract the anti-scientific discourses, among other initiatives, it is necessary to understand their motivations and arguments. In its document How to respond to vocal vaccine deniers in public, the WHO highlights that ‘Listening to [vocal vaccine deniers’] arguments and analyzing their common structure provides you with the necessary knowledge on how to effectively respond’ (2016, p. 26). In this line, various classifications of anti-science discourse have been proposed (Diethelm & McKee, 2009; Hansson, 2017) and mentioned extensively in studies that analyze anti-vaccine groups’ discourses.

However, while there are many studies that survey the antivaxxers’ messages on social networks in Europe and the United States (Ortiz-Sánchez et al., 2020; Wawrzuta et al., 2021), there are very few studies that analyze misinformation spread in Spanish-speaking countries (García & Aguilar, 2018).

In this article, we will analyze the discourse of the principal anti-vaccine groups in Latin America on the social network Twitter, categorize their types of reasoning, the content of their messages and compare our findings to uncover differences and similarities among these countries. The ultimate goal is to be able to develop tools that will allow us to counteract anti-scientific discourses.