biostudies-literatureUnknown18(1)Fues Wahl HMSDVaccine hesitancy is listed as one of the top 10 global health threats by the WHO. Existing studies investigating the relationship between vaccine hesitancy and social media have found that misinformation and vaccine concerns on social media can cause significant declines in vaccine coverage rates. The objective of this study was to provide insight into the dynamics of vaccine messages on Twitter in Scandinavia (Denmark, Norway, Sweden), by analyzing tweets in local languages during 2019. A validated measure, the 5C scale, was used to map relevant predictors of vaccination behavior, capturing the factors <i>confidence</i> (in vaccines and the system that delivers them), <i>complacency</i> (not perceiving diseases as high risk), <i>constraints</i> (structural and psychological barriers), <i>calculation</i> (engagement in extensive information searching) and <i>collective responsibility</i> (willingness to protect others). A total of 1794 tweets met the inclusion criteria (DK: 48%, NO: 15%, SE: 37%), predominantly tweeted by private users (86%). The HPV vaccine was mentioned in 81% of tweets. Tweets were classified as expressing <i>confidence</i> (61%), <i>complacency</i> (18%), <i>constraints</i> (15%), <i>calculation</i> (15%), and <i>collective responsibility</i> (4%). C<i>onfidence</i> in vaccines and the system that delivers them was expressed in 57%. A lack of <i>confidence</i> was expressed in 4% of all tweets, in combination with <i>calculation</i> in 39%. Analyzing public sentiment toward vaccination on Twitter is a useful tool to leverage for better understanding of the dynamics behind vaccine hesitancy. This analysis could provide actionable information for healthcare professionals and public health authorities to mitigate online misinformation and public vaccine concerns.Human vaccines & immunotherapeutics2026711https://www.ebi.ac.uk/biostudies/studies/S-EPMC8993101biostudies-literatureAnalysis of vaccine messages on social media (Twitter) in Scandinavia.PMC8993101Sahlin CNyaku MBencina GFues Wahl HWikman Erlandson BfalseAnalysis of vaccine messages on social media (Twitter) in Scandinavia.Vaccine hesitancy is listed as one of the top 10 global health threats by the WHO. Existing studies investigating the relationship between vaccine hesitancy and social media have found that misinformation and vaccine concerns on social media can cause significant declines in vaccine coverage rates. The objective of this study was to provide insight into the dynamics of vaccine messages on Twitter in Scandinavia (Denmark, Norway, Sweden), by analyzing tweets in local languages during 2019. A validated measure, the 5C scale, was used to map relevant predictors of vaccination behavior, capturing the factors <i>confidence</i> (in vaccines and the system that delivers them), <i>complacency</i> (not perceiving diseases as high risk), <i>constraints</i> (structural and psychological barriers), <i>calculation</i> (engagement in extensive information searching) and <i>collective responsibility</i> (willingness to protect others). A total of 1794 tweets met the inclusion criteria (DK: 48%, NO: 15%, SE: 37%), predominantly tweeted by private users (86%). The HPV vaccine was mentioned in 81% of tweets. Tweets were classified as expressing <i>confidence</i> (61%), <i>complacency</i> (18%), <i>constraints</i> (15%), <i>calculation</i> (15%), and <i>collective responsibility</i> (4%). C<i>onfidence</i> in vaccines and the system that delivers them was expressed in 57%. A lack of <i>confidence</i> was expressed in 4% of all tweets, in combination with <i>calculation</i> in 39%. Analyzing public sentiment toward vaccination on Twitter is a useful tool to leverage for better understanding of the dynamics behind vaccine hesitancy. This analysis could provide actionable information for healthcare professionals and public health authorities to mitigate online misinformation and public vaccine concerns.2022-01-01T00:00:00Z2022 Dec2025-04-04T07:33:39.925Z2025-04-04T07:33:39.925ZS-EPMC89931013510357910.1080/21645515.2022.2026711