{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,12]],"date-time":"2026-03-12T09:49:53Z","timestamp":1773308993520,"version":"3.50.1"},"reference-count":51,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2021,10,11]],"date-time":"2021-10-11T00:00:00Z","timestamp":1633910400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/PSI\/01662\/2020"],"award-info":[{"award-number":["UIDB\/PSI\/01662\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Do people want to be vaccinated against COVID-19? Herd immunity is dependent on individuals\u2019 willingness to be vaccinated since vaccination is not mandatory. Our main goal was to investigate people\u2019s intention to be vaccinated and their intentions to vaccinate their children. Moreover, we were interested in understanding the role of the personal characteristics, psychological factors, and the lockdown context on that decision. Therefore, we conducted an online survey during the lockdown in Portugal (15 January 2021 until 14 March 2021). Participants completed a socio-demographic questionnaire, questions about their intentions of being vaccinated, concerns about the vaccine, a COVID-19 attitudes and beliefs scale, a COVID-19 vaccine attitudes and beliefs scale, and the Domain-Specific Risk-Taking (DOSPERT) Scale. Our results showed that from the 649 participants, 63% of the participants reported being very likely to have the vaccine, while 60% reported being very likely to vaccinate their children. We conducted two linear regression models, explaining 65% of the variance for personal vaccination and 56% of the variance for children vaccination. We found that the COVID-19 vaccine general beliefs and attitudes were the main determinants of vaccination intention. Additionally, our proposed artificial neural network model was able to predict with 85% accuracy vaccination intention. Thus, our results suggest that psychological factors are an essential determinant of vaccination intention. Thus, public policy decision makers may use these insights for predicting vaccine hesitancy and designing effective vaccination communication strategies.<\/jats:p>","DOI":"10.3390\/vaccines9101161","type":"journal-article","created":{"date-parts":[[2021,10,11]],"date-time":"2021-10-11T21:45:32Z","timestamp":1633988732000},"page":"1161","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":53,"title":["Predicting COVID-19 Vaccination Intention: The Determinants of Vaccine Hesitancy"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1959-7671","authenticated-orcid":false,"given":"Nuno","family":"Fernandes","sequence":"first","affiliation":[{"name":"Psychology Research Center (CIPsi), School of Psychology, University of Minho, 4710-057 Braga, Portugal"}]},{"given":"Daniela","family":"Costa","sequence":"additional","affiliation":[{"name":"Psychology Research Center (CIPsi), School of Psychology, University of Minho, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4995-0539","authenticated-orcid":false,"given":"Diogo","family":"Costa","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8105-9148","authenticated-orcid":false,"given":"Jos\u00e9","family":"Keating","sequence":"additional","affiliation":[{"name":"Psychology Research Center (CIPsi), School of Psychology, University of Minho, 4710-057 Braga, Portugal"}]},{"given":"Joana","family":"Arantes","sequence":"additional","affiliation":[{"name":"Psychology Research Center (CIPsi), School of Psychology, University of Minho, 4710-057 Braga, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,11]]},"reference":[{"key":"ref_1","unstructured":"Chriscaden, K. (2021, May 13). Impact of COVID-19 on People\u2019s Livelihoods, Their Health and Our Food Systems. Available online: https:\/\/www.who.int\/news\/item\/13-10-2020-impact-of-covid-19-on-people\u2019s-livelihoods-their-health-and-our-food-systems."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1016\/S1473-3099(20)30120-1","article-title":"An interactive web-based dashboard to track COVID-19 in real time","volume":"20","author":"Dong","year":"2020","journal-title":"Lancet. Infect. Dis."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41541-020-0188-3","article-title":"COVID-19 vaccines: Breaking record times to first-in-human trials","volume":"5","author":"Kim","year":"2020","journal-title":"NPJ Vaccines"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1718","DOI":"10.1080\/10410236.2020.1838096","article-title":"Considering emotion in COVID-19 vaccine communication: Addressing vaccine hesitancy and fostering vaccine confidence","volume":"35","author":"Chou","year":"2020","journal-title":"Health Commun."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Thunstrom, L., Ashworth, M., Finnoff, D., and Newbold, S. (2020). Hesitancy towards a COVID-19 vaccine and prospects for herd immunity. SSRN, 1\u201351.","DOI":"10.2139\/ssrn.3593098"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"977","DOI":"10.1007\/s10198-020-01208-6","article-title":"Once we have it, will we use it? A European survey on willingness to be vaccinated against COVID-19","volume":"21","author":"Varghese","year":"2020","journal-title":"Eur. J. Health Econ."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1038\/s41562-021-01056-1","article-title":"Measuring the impact of COVID-19 vaccine misinformation on vaccination intent in the UK and USA","volume":"5","author":"Piatek","year":"2021","journal-title":"Nat. Hum. Behav."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1126\/science.372.6537.14","article-title":"Side effect worry grows for AstraZeneca vaccine","volume":"372","author":"Vogel","year":"2021","journal-title":"Science"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1289","DOI":"10.1126\/science.abi6488","article-title":"Volatility of vaccine confidence","volume":"371","author":"Larson","year":"2021","journal-title":"Science"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4180","DOI":"10.1016\/j.vaccine.2015.04.040","article-title":"Strategies for addressing vaccine hesitancy\u2014A systematic review","volume":"33","author":"Jarrett","year":"2015","journal-title":"Vaccine"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1136\/bmjgh-2020-004206","article-title":"Social media and vaccine hesitancy","volume":"5","author":"Wilson","year":"2020","journal-title":"BMJ Glob. Health"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"7002","DOI":"10.1016\/j.vaccine.2020.09.041","article-title":"Intention to participate in a COVID-19 vaccine clinical trial and to get vaccinated against COVID-19 in France during the pandemic","volume":"38","author":"Detoc","year":"2020","journal-title":"Vaccine"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1612","DOI":"10.1080\/21645515.2020.1846397","article-title":"COVID-19 vaccination intention in the UK: Results from the COVID-19 vaccination acceptability study (CoVAccS), a nationally representative cross-sectional survey","volume":"17","author":"Sherman","year":"2021","journal-title":"Hum. Vaccin. Immunother."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"263","DOI":"10.2307\/1914185","article-title":"Prospect theory: An analysis of decision under risk","volume":"47","author":"Kahneman","year":"1979","journal-title":"Econometrica"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"113642","DOI":"10.1016\/j.socscimed.2020.113638","article-title":"Correlates and disparities of COVID-19 vaccine hesitancy","volume":"272","author":"Callaghan","year":"2021","journal-title":"Soc. Sci. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1007\/s40797-019-00089-w","article-title":"Vaccination as a trade-off between risks","volume":"5","author":"Crainich","year":"2019","journal-title":"Ital. Econ. J."},{"key":"ref_17","first-page":"3","article-title":"The effect of frames on COVID-19 vaccine hesitancy","volume":"3","author":"Palm","year":"2021","journal-title":"MedRxiv"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/0749-5978(91)90020-T","article-title":"The theory of planned behavior","volume":"50","author":"Ajzen","year":"1991","journal-title":"Organ. Behav. Hum. Decis. Process."},{"key":"ref_19","first-page":"151","article-title":"Social Influence: Social Norms, Conformity and Compliance","volume":"Volume 2","author":"Gilbert","year":"1998","journal-title":"The Handbook of Social Psychology"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/0010-0285(73)90033-9","article-title":"Availability: A heuristic for judging frequency and probability","volume":"5","author":"Tversky","year":"1973","journal-title":"Cogn. Psychol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1093\/cid\/ciaa1425","article-title":"Warp speed for COVID-19 vaccines: Why are children stuck in neutral?","volume":"73","author":"Anderson","year":"2020","journal-title":"Clin. Infect. Dis."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1016\/0895-4356(96)00007-8","article-title":"Cognitive processes and the decisions of some parents to forego pertussis vaccination for their children","volume":"49","author":"Meszaros","year":"1996","journal-title":"J. Clin. Epidemiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"7789","DOI":"10.1016\/j.vaccine.2020.10.027","article-title":"Parents\u2019 and guardians\u2019 views on the acceptability of a future COVID-19 vaccine: A multi-methods study in England","volume":"38","author":"Bell","year":"2020","journal-title":"Vaccine"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1017\/S1930297500000334","article-title":"A Domain-Specific Risk-Taking (DOSPERT) scale for adult populations","volume":"1","author":"Blais","year":"2006","journal-title":"Judgm. Decis. Mak."},{"key":"ref_25","unstructured":"Silva, R. (2012). Risk Profiling and the DOSPERT Scale: An Approach Using Prospect Theory. [Master\u2019s Thesis, Universidade T\u00e9cnica de Lisboa]. Available online: http:\/\/hdl.handle.net\/10400.5\/10351."},{"key":"ref_26","unstructured":"(2021, January 07). Qualtrics. Qualtrics, Provo, UT, USA. Available online: https:\/\/www.qualtrics.com."},{"key":"ref_27","unstructured":"R Core Team (2021, September 05). R: A Language and Environment for Statistical Computing, Available online: https:\/\/www.R-project.org\/."},{"key":"ref_28","unstructured":"RStudio Team (2021, September 05). RStudio: Integrated Development Environment for R. RStudio, PBC, Boston, MA, USA. Available online: http:\/\/www.rstudio.com\/."},{"key":"ref_29","first-page":"2825","article-title":"Scikit-learn: Machine learning in Python","volume":"12","author":"Pedregosa","year":"2011","journal-title":"J. Mach. Learn. Res."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"200742","DOI":"10.1098\/rsos.200742","article-title":"Changes in risk perception and self-reported protective behaviour during the first week of the COVID-19 pandemic in the United States","volume":"7","author":"Wise","year":"2020","journal-title":"R. Soc. Open. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Ripley, B.D. (1996). Pattern Recognition and Neural Networks, Cambridge University Press.","DOI":"10.1017\/CBO9780511812651"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s41256-020-00175-y","article-title":"Application of artificial neural networks to predict the COVID-19 outbreak","volume":"5","author":"Niazkar","year":"2020","journal-title":"Glob. Health Res. Policy"},{"key":"ref_33","first-page":"53","article-title":"Forecasting of Covid-19 cases based on prediction using artificial neural network curve fitting technique","volume":"6","author":"Tamang","year":"2020","journal-title":"Glob. J. Environ. Sci. Manag."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Soares, P., Rocha, J.V., Moniz, M., Gama, A., Laires, P.A., Pedro, A.R., Dias, S., Leite, A., and Nunes, C. (2021). Factors associated with COVID-19 vaccine hesitancy. Vaccines, 9.","DOI":"10.3390\/vaccines9030300"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1158\/2159-8290.CD-20-1817","article-title":"Priority COVID-19 vaccination for patients with cancer while vaccine supply is limited","volume":"11","author":"Ribas","year":"2021","journal-title":"Cancer Discov."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Kelkar, A.H., Blake, A.J., Cherabuddi, K., Cornett, H., McKee, B.L., and Cogle, C.R. (2020). Vaccine enthusiasm and hesitancy in cancer patients and the impact of a webinar. Healthcare, 9.","DOI":"10.3390\/healthcare9030351"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1038\/s41562-020-0884-z","article-title":"Using social and behavioural science to support COVID-19 pandemic response","volume":"4","author":"Bavel","year":"2020","journal-title":"Nat. Hum. Behav."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2060","DOI":"10.1016\/j.vaccine.2021.03.018","article-title":"Social norms and vaccine uptake: College students\u2019 COVID vaccination intentions, attitudes, and estimated peer norms and comparisons with influenza vaccine","volume":"39","author":"Scott","year":"2021","journal-title":"Vaccine"},{"key":"ref_39","first-page":"2928","article-title":"Inoculating against fake news about COVID-19","volume":"11","author":"Roozenbeek","year":"2020","journal-title":"Front. Psychol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"e0250123","DOI":"10.1371\/journal.pone.0250123","article-title":"COVID-19 and vaccine hesitancy: A longitudinal study","volume":"16","author":"Fridman","year":"2021","journal-title":"PLoS ONE"},{"key":"ref_41","unstructured":"DGS (2021, May 29). Ponto de Situa\u00e7\u00e3o Atual em Portugal. Available online: https:\/\/covid19.min-saude.pt\/ponto-de-situacao-atual-em-portugal\/."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1002\/hec.3620","article-title":"Risk-taking in vaccination, surgery, and gambling environments: Evidence from a framed laboratory experiment","volume":"26","author":"Binder","year":"2017","journal-title":"Health Econ."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Guo, N., Wang, J., Nicholas, S., Maitland, E., and Zhu, D. (2020). Behavioral differences in the preference for hepatitis B virus vaccination: A discrete choice experiment. Vaccines, 8.","DOI":"10.3390\/vaccines8030527"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1287\/mksc.16.4.370","article-title":"A comparative analysis of neural networks and statistical methods for predicting consumer choice","volume":"16","author":"West","year":"1997","journal-title":"Mark. Sci."},{"key":"ref_45","unstructured":"Gu, Y. (2020, October 05). COVID-19 Projections Using Machine Learning. Available online: https:\/\/covid19-projections.com."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1177\/001872674700100103","article-title":"Frontiers in group dynamics: Concept, method and reality in social science; social equilibria and social change","volume":"1","author":"Lewin","year":"1947","journal-title":"Hum. Relat."},{"key":"ref_47","first-page":"843","article-title":"Do norms matter? Examining norm-based messages in HPV vaccination promotion","volume":"25","author":"Xiao","year":"2020","journal-title":"Health Commun."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1177\/001088040204300204","article-title":"The science and practice of persuasion","volume":"43","author":"Cialdini","year":"2002","journal-title":"Cornell Hosp. Q."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"m4944","DOI":"10.1136\/bmj.m4944","article-title":"Covid-19: What have we learnt about the new variant in the UK?","volume":"371","author":"Mahase","year":"2020","journal-title":"BMJ"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1021\/ci0342472","article-title":"The problem of overfitting","volume":"44","author":"Hawkins","year":"2004","journal-title":"J. Chem. Inf. Comput. Sci."},{"key":"ref_51","first-page":"360","article-title":"Potential limitations in COVID-19 machine learning due to data source variability: A case study in the nCov2019 dataset","volume":"28","author":"Romero","year":"2020","journal-title":"J. Am. Med. Inform. 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