{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,19]],"date-time":"2025-12-19T18:38:05Z","timestamp":1766169485369,"version":"3.48.0"},"reference-count":61,"publisher":"Public Library of Science (PLoS)","issue":"12","license":[{"start":{"date-parts":[[2025,12,19]],"date-time":"2025-12-19T00:00:00Z","timestamp":1766102400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["P20GM113109"],"award-info":[{"award-number":["P20GM113109"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>In this work, we study English-language vaccine discourse in social media posts, specifically posts on X (formerly Twitter), in seven years before the COVID-19 outbreak (2013 to 2019) and three years after the outbreak was first reported (2020 to 2022). Drawing on theories from social cognition and the stereotype content model in Social Psychology, we analyze how English speakers talk about vaccines on social media to understand the evolving narrative around vaccines in social media posts. To do that, we first introduce a novel dataset comprising 18.7 million curated posts on vaccine discourse from 2013 to 2022. This extensive collection\u2014filtered down from an initial 129 million posts through rigorous preprocessing\u2014captures both pre-COVID and COVID-19 periods, offering valuable insights into the evolution of English-speaking X users\u2019 perceptions related to vaccines. Our analysis shows that the COVID-19 pandemic led to complex shifts in X users\u2019 sentiment and discourse around vaccines. We observe that negative emotion word usage decreased during the pandemic, with notable rises in usage of surprise, and trust related emotion words. Furthermore, vaccine-related language tended to use more warmth-focused words associated with trustworthiness, along with positive, competence-focused words during the early days of the pandemic, with a marked rise in negative word usage towards the end of the pandemic, possibly reflecting a growing vaccine hesitancy and skepticism.<\/jats:p>","DOI":"10.1371\/journal.pone.0337911","type":"journal-article","created":{"date-parts":[[2025,12,19]],"date-time":"2025-12-19T18:33:39Z","timestamp":1766169219000},"page":"e0337911","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["The shifting landscape of vaccine discourse: Insights from a decade of pre- to post-COVID-19 vaccine posts on social media"],"prefix":"10.1371","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7801-2958","authenticated-orcid":true,"given":"Nikesh","family":"Gyawali","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6440-0914","authenticated-orcid":true,"given":"Doina","family":"Caragea","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cornelia","family":"Caragea","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Saif M.","family":"Mohammad","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2025,12,19]]},"reference":[{"issue":"12","key":"pone.0337911.ref001","doi-asserted-by":"crossref","first-page":"865","DOI":"10.1038\/nri3085","article-title":"Vaccines for the twenty-first century society","volume":"11","author":"R Rappuoli","year":"2011","journal-title":"Nat Rev Immunol."},{"issue":"4","key":"pone.0337911.ref002","doi-asserted-by":"crossref","first-page":"308","DOI":"10.1177\/1754073915590621","article-title":"This time, it\u2019s real: affective flexibility, time scales, feedback loops, and the regulation of emotion","volume":"7","author":"T Hollenstein","year":"2015","journal-title":"Emotion Review."},{"issue":"6","key":"pone.0337911.ref003","doi-asserted-by":"crossref","first-page":"1042","DOI":"10.1037\/a0020962","article-title":"Feelings change: accounting for individual differences in the temporal dynamics of affect","volume":"99","author":"P Kuppens","year":"2010","journal-title":"J Pers Soc Psychol."},{"key":"pone.0337911.ref004","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.copsyc.2017.06.004","article-title":"Emotion dynamics","volume":"17","author":"P Kuppens","year":"2017","journal-title":"Curr Opin Psychol."},{"issue":"1","key":"pone.0337911.ref005","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1177\/0963721416666518","article-title":"No time like the present","volume":"26","author":"EL Hamaker","year":"2017","journal-title":"Curr Dir Psychol Sci."},{"issue":"8","key":"pone.0337911.ref006","doi-asserted-by":"crossref","first-page":"1121","DOI":"10.1080\/02699930441000030","article-title":"Language use of depressed and depression-vulnerable college students","volume":"18","author":"S Rude","year":"2004","journal-title":"Cognition & Emotion."},{"key":"pone.0337911.ref007","doi-asserted-by":"crossref","unstructured":"Ekman P. Facial expressions. The handbook of cognition and emotion. John Wiley & Sons; 1999.","DOI":"10.1002\/0470013494.ch16"},{"key":"pone.0337911.ref008","unstructured":"Plutchik R. The emotions. University Press of America; 1991."},{"key":"pone.0337911.ref009","doi-asserted-by":"crossref","unstructured":"Bandura A. Social cognitive theory: an agentic perspective on human nature. John Wiley & Sons; 2023.","DOI":"10.1002\/9781394259069"},{"issue":"6","key":"pone.0337911.ref010","doi-asserted-by":"crossref","first-page":"878","DOI":"10.1037\/0022-3514.82.6.878","article-title":"A model of (often mixed) stereotype content: competence and warmth respectively follow from perceived status and competition.","volume":"82","author":"ST Fiske","year":"2002","journal-title":"Journal of Personality and Social Psychology."},{"key":"pone.0337911.ref011","doi-asserted-by":"crossref","unstructured":"Bodenhausen GV, Kang SK, Peery D. Social categorization and the perception of social groups. The SAGE Handbook of Social Cognition. SAGE Publications Ltd.; 2012. p. 311\u201329. https:\/\/doi.org\/10.4135\/9781446247631.n16","DOI":"10.4135\/9781446247631.n16"},{"issue":"2","key":"pone.0337911.ref012","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1177\/0963721417738825","article-title":"Stereotype content: Warmth and competence endure","volume":"27","author":"ST Fiske","year":"2018","journal-title":"Curr Dir Psychol Sci."},{"key":"pone.0337911.ref013","doi-asserted-by":"crossref","first-page":"1810","DOI":"10.3389\/fpsyg.2016.01810","article-title":"Facets of the fundamental content dimensions: agency with competence and assertiveness-communion with warmth and morality","volume":"7","author":"AE Abele","year":"2016","journal-title":"Front Psychol."},{"issue":"8","key":"pone.0337911.ref014","doi-asserted-by":"crossref","first-page":"8521","DOI":"10.3758\/s13428-024-02489-y","article-title":"Validating a brief measure of four facets of social evaluation","volume":"56","author":"A Koch","year":"2024","journal-title":"Behav Res Methods."},{"key":"pone.0337911.ref015","unstructured":"Fiske STT, Taylor SE. Social cognition: from brains to culture. SAGE Publications Ltd.; 2020."},{"issue":"2","key":"pone.0337911.ref016","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.jcps.2011.10.003","article-title":"Brands as relationship partners: Warmth, competence, and in-between","volume":"22","author":"S Fournier","year":"2012","journal-title":"J Consum Psychol."},{"key":"pone.0337911.ref017","doi-asserted-by":"crossref","unstructured":"Teodorescu D, Mohammad S. Evaluating emotion arcs across languages: bridging the global divide in sentiment analysis. In: Findings of the Association for Computational Linguistics: EMNLP 2023 . 2023. p. 4124\u201337.","DOI":"10.18653\/v1\/2023.findings-emnlp.271"},{"issue":"9","key":"pone.0337911.ref018","article-title":"Revealing public opinion towards COVID-19 vaccines with Twitter data in the United States: spatiotemporal perspective","volume":"23","author":"T Hu","year":"2021","journal-title":"J Med Internet Res."},{"key":"pone.0337911.ref019","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1016\/j.eswa.2018.09.009","article-title":"Monitoring the public opinion about the vaccination topic from tweets analysis","volume":"116","author":"E D\u2019Andrea","year":"2019","journal-title":"Expert Systems with Applications."},{"key":"pone.0337911.ref020","doi-asserted-by":"crossref","first-page":"1236","DOI":"10.1609\/icwsm.v16i1.19374","article-title":"VaccinEU: COVID-19 vaccine conversations on Twitter in French, German and Italian","volume":"16","author":"MD Giovanni","year":"2022","journal-title":"ICWSM."},{"key":"pone.0337911.ref021","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.ijid.2021.05.059","article-title":"An analysis of COVID-19 vaccine sentiments and opinions on Twitter","volume":"108","author":"S Yousefinaghani","year":"2021","journal-title":"Int J Infect Dis."},{"issue":"2","key":"pone.0337911.ref022","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1016\/j.dsx.2021.02.031","article-title":"Analyzing the attitude of Indian citizens towards COVID-19 vaccine - A text analytics study","volume":"15","author":"SV Praveen","year":"2021","journal-title":"Diabetes Metab Syndr."},{"issue":"8","key":"pone.0337911.ref023","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1016\/j.healthpol.2021.06.006","article-title":"The early weeks of the Italian Covid-19 outbreak: sentiment insights from a Twitter analysis","volume":"125","author":"S De Rosis","year":"2021","journal-title":"Health Policy."},{"issue":"2","key":"pone.0337911.ref024","doi-asserted-by":"crossref","first-page":"14","DOI":"10.3390\/bdcc4020014","article-title":"#lockdown: network-enhanced emotional profiling in the time of COVID-19","volume":"4","author":"M Stella","year":"2020","journal-title":"BDCC."},{"issue":"10","key":"pone.0337911.ref025","doi-asserted-by":"crossref","DOI":"10.2196\/40323","article-title":"Emotions and topics expressed on twitter during the COVID-19 pandemic in the United Kingdom: comparative geolocation and text mining analysis","volume":"24","author":"H Alhuzali","year":"2022","journal-title":"J Med Internet Res."},{"key":"pone.0337911.ref026","doi-asserted-by":"crossref","first-page":"118715","DOI":"10.1016\/j.eswa.2022.118715","article-title":"Covid-19 vaccine hesitancy: text mining, sentiment analysis and machine learning on COVID-19 vaccination Twitter dataset","volume":"212","author":"M Qorib","year":"2023","journal-title":"Expert Syst Appl."},{"key":"pone.0337911.ref027","first-page":"1","article-title":"Sentiment analysis tracking of COVID-19 vaccine through tweets","author":"A Sarirete","year":"2022","journal-title":"J Ambient Intell Humaniz Comput."},{"issue":"33","key":"pone.0337911.ref028","doi-asserted-by":"crossref","first-page":"4844","DOI":"10.1016\/j.vaccine.2023.06.058","article-title":"Public perception of COVID-19 vaccines through analysis of Twitter content and users","volume":"41","author":"SN Saleh","year":"2023","journal-title":"Vaccine."},{"key":"pone.0337911.ref029","doi-asserted-by":"crossref","DOI":"10.2196\/41319","article-title":"Dynamics of the negative discourse toward COVID-19 vaccines: topic modeling study and an annotated data set of Twitter posts","volume":"25","author":"G Lindel\u00f6f","year":"2023","journal-title":"J Med Internet Res."},{"key":"pone.0337911.ref030","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1609\/icwsm.v17i1.22213","article-title":"VaxxHesitancy: a dataset for studying hesitancy towards COVID-19 vaccination on Twitter","volume":"17","author":"Y Mu","year":"2023","journal-title":"ICWSM."},{"issue":"1","key":"pone.0337911.ref031","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1080\/21548455.2023.2185829","article-title":"Understanding communication about the COVID-19 vaccines: analysis of emergent sentiments and topics of discussion on Twitter during the initial phase of the vaccine rollout","volume":"14","author":"E Burwell","year":"2023","journal-title":"International Journal of Science Education, Part B."},{"issue":"6","key":"pone.0337911.ref032","article-title":"COVID-19 vaccine-related discussion on Twitter: topic modeling and sentiment analysis","volume":"23","author":"JC Lyu","year":"2021","journal-title":"J Med Internet Res."},{"issue":"3","key":"pone.0337911.ref033","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0318544","article-title":"Modelling the mitigation of anti-vaccine opinion propagation to suppress epidemic spread: a computational approach","volume":"20","author":"S Alahmadi","year":"2025","journal-title":"PLoS One."},{"key":"pone.0337911.ref034","doi-asserted-by":"crossref","first-page":"1276","DOI":"10.1609\/icwsm.v18i1.31388","article-title":"How COVID-19 has impacted the anti-vaccine discourse: a large-scale Twitter study spanning pre-COVID and post-COVID era","volume":"18","author":"S Poddar","year":"2024","journal-title":"ICWSM."},{"issue":"5","key":"pone.0337911.ref035","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0268784","article-title":"COVID-19 vaccine: a 2021 analysis of perceptions on vaccine safety and promise in a U.S. sample","volume":"17","author":"VC Osuji","year":"2022","journal-title":"PLoS One."},{"key":"pone.0337911.ref036","unstructured":"Aggarwal J, Rabinovich E, Stevenson S. Exploration of gender differences in COVID-19 discourse on reddit. In: Verspoor K, Cohen KB, Dredze M, Ferrara E, May J, Munro R, et al. editors. Proceedings of the 1st Workshop on NLP for COVID-19 at ACL 2020 . Online: Association for Computational Linguistics; 2020. https:\/\/aclanthology.org\/2020.nlpcovid19-acl.13\/"},{"issue":"5","key":"pone.0337911.ref037","doi-asserted-by":"crossref","first-page":"1596","DOI":"10.1177\/0265407521998460","article-title":"Examining the language of solitude versus loneliness in tweets","volume":"38","author":"WE Hipson","year":"2021","journal-title":"Journal of Social and Personal Relationships."},{"issue":"1","key":"pone.0337911.ref038","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1111\/josi.12210","article-title":"Warmth-competence tradeoffs in impression management across race and social-class divides","volume":"73","author":"JK Swencionis","year":"2017","journal-title":"Journal of Social Issues."},{"key":"pone.0337911.ref039","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.copsyc.2017.07.033","article-title":"How social-class stereotypes maintain inequality","volume":"18","author":"F Durante","year":"2017","journal-title":"Curr Opin Psychol."},{"issue":"6","key":"pone.0337911.ref040","doi-asserted-by":"crossref","first-page":"973","DOI":"10.1002\/ejsp.595","article-title":"Two dimensions of interpersonal attitudes: liking depends on communion, respect depends on agency","volume":"39","author":"B Wojciszke","year":"2009","journal-title":"Euro J Social Psych."},{"key":"pone.0337911.ref041","doi-asserted-by":"crossref","unstructured":"Fiske ST, Durante F, et al. Never trust a politician? Collective distrust, relational accountability, and voter response. Power, politics, and paranoia: why people are suspicious of their leaders. 2014. p. 91\u2013105.","DOI":"10.1017\/CBO9781139565417.009"},{"key":"pone.0337911.ref042","doi-asserted-by":"crossref","unstructured":"Fiske ST, Durante F. Stereotype content across cultures. Handbook of Advances in Culture and Psychology, Volume 6. Oxford University Press; 2016. p. 209\u201358. https:\/\/doi.org\/10.1093\/acprof:oso\/9780190458850.003.0005","DOI":"10.1093\/acprof:oso\/9780190458850.003.0005"},{"key":"pone.0337911.ref043","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.jecp.2015.08.009","article-title":"The development of stereotype content: the use of warmth and competence in assessing social groups","volume":"141","author":"G Roussos","year":"2016","journal-title":"J Exp Child Psychol."},{"key":"pone.0337911.ref044","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.riob.2011.10.004","article-title":"The dynamics of warmth and competence judgments, and their outcomes in organizations","volume":"31","author":"AJC Cuddy","year":"2011","journal-title":"Research in Organizational Behavior."},{"key":"pone.0337911.ref045","doi-asserted-by":"crossref","unstructured":"Abele AE, Wojciszke B. Communal and agentic content in social cognition: a dual perspective model. In: Advances in experimental social psychology. vol. 50. Elsevier; 2014. p. 195\u2013255.","DOI":"10.1016\/B978-0-12-800284-1.00004-7"},{"issue":"32","key":"pone.0337911.ref046","doi-asserted-by":"crossref","first-page":"11087","DOI":"10.1073\/pnas.0805664105","article-title":"The functional basis of face evaluation","volume":"105","author":"NN Oosterhof","year":"2008","journal-title":"Proc Natl Acad Sci U S A."},{"issue":"2","key":"pone.0337911.ref047","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.tics.2006.11.005","article-title":"Universal dimensions of social cognition: Warmth and competence","volume":"11","author":"ST Fiske","year":"2007","journal-title":"Trends Cogn Sci."},{"issue":"2","key":"pone.0337911.ref048","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1037\/0022-3514.93.2.234","article-title":"Group virtue: the importance of morality (vs. competence and sociability) in the positive evaluation of in-groups","volume":"93","author":"CW Leach","year":"2007","journal-title":"J Pers Soc Psychol."},{"key":"pone.0337911.ref049","unstructured":"Wang W, Wei F, Dong L, Bao H, Yang N, Zhou M. MiniLM: deep self-attention distillation for task-agnostic compression of pre-trained transformers. In: Advances in Neural Information Processing Systems. vol. 33. Curran Associates, Inc.; 2020. p. 5776\u201388. https:\/\/proceedings.neurips.cc\/paper_files\/paper\/2020\/hash\/3f5ee243547dee91fbd053c1c4a845aa-Abstract.html"},{"key":"pone.0337911.ref050","unstructured":"Vishnubhotla K, Mohammad SM. Tweet emotion dynamics: emotion word usage in Tweets from US and Canada. In: Proceedings of the Thirteenth Language Resources and Evaluation Conference. Marseille, France: European Language Resources Association; 2022. p. 4162\u201376. https:\/\/aclanthology.org\/2022.lrec-1.442\/"},{"issue":"9","key":"pone.0337911.ref051","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0256153","article-title":"Emotion dynamics in movie dialogues","volume":"16","author":"WE Hipson","year":"2021","journal-title":"PLoS One."},{"key":"pone.0337911.ref052","unstructured":"Mohammad S, Turney P. Emotions evoked by common words and phrases: using mechanical turk to create an emotion Lexicon. In: Proceedings of the NAACL HLT 2010 Workshop on Computational Approaches to Analysis and Generation of Emotion in Text. Los Angeles, CA: Association for Computational Linguistics; 2010. p. 26\u201334. https:\/\/aclanthology.org\/W10-0204"},{"issue":"3","key":"pone.0337911.ref053","doi-asserted-by":"crossref","first-page":"436","DOI":"10.1111\/j.1467-8640.2012.00460.x","article-title":"Crowdsourcing a word\u2013emotion association lexicon","volume":"29","author":"SM Mohammad","year":"2012","journal-title":"Computational Intelligence."},{"key":"pone.0337911.ref054","doi-asserted-by":"crossref","unstructured":"Mohammad S. Obtaining reliable human ratings of valence, arousal, and dominance for 20,000 English words. In: Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). Melbourne, Australia; 2018. p. 174\u201384. http:\/\/aclweb.org\/anthology\/P18-1017","DOI":"10.18653\/v1\/P18-1017"},{"key":"pone.0337911.ref055","doi-asserted-by":"crossref","unstructured":"Mohammad SM. Words of Warmth: trust and sociability norms for over 26k English words. In: Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2025. p. 18830\u201350. https:\/\/doi.org\/10.18653\/v1\/2025.acl-long.922","DOI":"10.18653\/v1\/2025.acl-long.922"},{"issue":"7","key":"pone.0337911.ref056","doi-asserted-by":"crossref","first-page":"984","DOI":"10.1177\/0956797610372634","article-title":"Emotional inertia and psychological maladjustment","volume":"21","author":"P Kuppens","year":"2010","journal-title":"Psychol Sci."},{"issue":"5","key":"pone.0337911.ref057","doi-asserted-by":"crossref","first-page":"739","DOI":"10.1037\/emo0000384","article-title":"A multivariate statistical model for emotion dynamics","volume":"18","author":"T Krone","year":"2018","journal-title":"Emotion."},{"key":"pone.0337911.ref058","doi-asserted-by":"crossref","unstructured":"Kilgarriff A. Word senses. Text, speech and language technology. Netherlands: Springer; 2007. p. 29\u201346. https:\/\/doi.org\/10.1007\/978-1-4020-4809-8_2","DOI":"10.1007\/978-1-4020-4809-8_2"},{"issue":"10","key":"pone.0337911.ref059","doi-asserted-by":"crossref","first-page":"7243","DOI":"10.1007\/s10994-024-06587-y","article-title":"Evaluating large language models for user stance detection on X (Twitter)","volume":"113","author":"M Gambini","year":"2024","journal-title":"Mach Learn."},{"key":"pone.0337911.ref060","unstructured":"Dubey A, Jauhri A, Pandey A, Kadian A, Al-Dahle A, Letman A, et al. The llama 3 herd of models. arXiv preprint arXiv:240721783. 2024."},{"key":"pone.0337911.ref061","doi-asserted-by":"crossref","unstructured":"Renze M. The effect of sampling temperature on problem solving in large language models. In: Findings of the Association for Computational Linguistics: EMNLP 2024 . 2024. p. 7346\u201356.","DOI":"10.18653\/v1\/2024.findings-emnlp.432"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0337911","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,19]],"date-time":"2025-12-19T18:33:53Z","timestamp":1766169233000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0337911"}},"subtitle":[],"editor":[{"given":"Carlos","family":"Carrasco-Farr\u00e9","sequence":"first","affiliation":[],"role":[{"role":"editor","vocabulary":"crossref"}]}],"short-title":[],"issued":{"date-parts":[[2025,12,19]]},"references-count":61,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2025,12,19]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0337911","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,19]]}}}