AUTHOR=Machado Júnior Celso , Mantovani Daielly Melina Nassif , de Sandes-Guimarães Luísa Veras , Romeiro Maria do Carmo , Furlaneto Cristiane Jaciara , Bazanini Roberto 

TITLE=Volatility of the COVID-19 vaccine hesitancy: sentiment analysis conducted in Brazil

JOURNAL=Frontiers in Public Health

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2023.1192155

DOI=10.3389/fpubh.2023.1192155

ISSN=2296-2565

ABSTRACT=Background: Vaccine hesitancy is a phenomenon that can interfere with the expansion of vaccination coverage and is positioned as one of the top ten global health threats. Previous studies have explored factors that affect vaccine hesitancy, how it behaves in different locations, and the profile of individuals in which it is most present. However, few studies have analyzed the volatility of vaccine hesitancy.
Objective: Identify the volatility of vaccine hesitancy manifested in social media.
Methods: Twitter's academic application programming interface was used to retrieve all tweets in Brazilian Portuguese mentioning the COVID-19 vaccine in three months (October 2020, June 2021, and October 2021), retrieving 1,048,576 tweets. A sentiment analysis was performed using the Orange software with the lexicon Multilingual sentiment in Portuguese.
Results: The feelings associated with vaccine hesitancy were volatile within one month, as well as throughout the vaccination process, being positioned as a resilient phenomenon. The themes that nurture vaccine hesitancy change dynamically and swiftly and are often associated with other topics that are also affecting society.  
Conclusion: People that manifest the vaccine hesitancy present arguments that vary in a short period of time, what demand that government strategies to mitigate vaccine hesitancy effects be agile and counteract the expressed fear, by presenting scientific arguments. Contribution to the field statement
Contribution to the field statement
Vaccine hesitancy has a major impact on the health of the population, as it is among the top ten threats to global health. Although vaccine hesitancy is dynamic and manifests itself under the influence of many variables, no study to date has analyzed the volatility of this phenomenon through social network analysis. The data resulting from this research positions vaccine hesitancy as a volatile phenomenon that manifests itself combined with other themes being discussed by society. The association of vaccine hesitancy with other social themes implies a constant change of arguments to justify the fear of being vaccinated. This alternation of social issues that are embodied in vaccine hesitancy can be observed in intervals of days and months.