Citation: Rogowska, A.M.; Chilicka, K.; Ochnik, D.; Paradowska, M.; Nowicka, D.; Bojarski, D.; Tomasiewicz, M.; Filipowicz, Z.; Grabarczyk, M.; Babi ´ nska, Z. Network Analysis of Well-Being Dimensions in Vaccinated and Unvaccinated Samples of University Students from Poland during the Fourth Wave of the COVID-19 Pandemic. Vaccines 2022, 10, 1334. https://doi.org/10.3390/ vaccines10081334 Academic Editor: François Meurens Received: 18 July 2022 Accepted: 15 August 2022 Published: 17 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Article Network Analysis of Well-Being Dimensions in Vaccinated and Unvaccinated Samples of University Students from Poland during the Fourth Wave of the COVID-19 Pandemic Aleksandra M. Rogowska 1, * , Karolina Chilicka 2 , Dominika Ochnik 3 , Maria Paradowska 4 , Dominika Nowicka 5 , Dawid Bojarski 4 , Maciej Tomasiewicz 6 , Zuzanna Filipowicz 7 , Maksymilian Grabarczyk 8 and Zuzanna Babi ´ nska 9 1 Institute of Psychology, University of Opole, 45-052 Opole, Poland 2 Department of Health Sciences, University of Opole, 45-040 Opole, Poland 3 Faculty of Medicine, University of Technology, 40-555 Katowice, Poland 4 Faculty of Psychology and Cognitive Studies, Adam Mickiewicz University in Poznan, 60-568 Poznan, Poland 5 Faculty of Sociology, University of Warsaw, 00-927 Warsaw, Poland 6 Faculty of Medicine,Wroclaw Medical University, 50-367 Wroclaw, Poland 7 Department of Pharmacology, Medical University of Bialystok, 15-089 Bialystok, Poland 8 Faculty of Medicine, Poznan University of Medical Sciences, 61-701 Poznan, Poland 9 Institute of the Middle and the Far East, Faculty of International and Political Studies, Jagiellonian University, 30-063 Krakov, Poland * Correspondence: arogowska@uni.opole.pl Abstract: Although numerous studies investigated the predictors of vaccination intention and decision, little is known about the relationship between vaccination and well-being. This study compares the physical and mental health dimensions among vaccinated and unvaccinated people. In a cross-sectional online survey, 706 university students from Poland (mean age of 23 years, 76% of women) participated in this study during the fourth pandemic wave (November–December 2021). Standardized questionnaires with a Likert response scale were included in the survey to measure spirituality, exposure to the COVID-19 pandemic, perceived physical health, stress, coronavirus- related PTSD, fear of COVID-19, anxiety, depression, and life satisfaction. Consistent with the fuzzy-trace theory, the unvaccinated sample was younger and scored significantly lower than the vaccinated group in exposure to COVID-19, perceived physical health, stress, coronavirus-related PTSD, fear of COVID-19, and depression, while higher in life satisfaction. The network analysis showed that mental health plays a crucial role in both groups, with the central influence of anxiety and stress on depression and life satisfaction. The message on vaccination to university students should focus on the benefits of vaccination in maintaining the status quo of good health and well-being. Campus prevention programs should primarily aim to reduce anxiety, stress, and negative emotions by teaching students coping strategies, relaxation techniques, and mindfulness. Keywords: mental health; network analysis; physical health; subjective well-being; university students; vaccination intention and decision 1. Introduction The COVID-19 pandemic significantly impacted well-being, deteriorating populations’ physical and mental health worldwide. Several restrictions were introduced during the lock- down, such as social distancing and isolation, wearing masks, periodically closing schools, universities, or workplaces, losing jobs, and deteriorating the economic situation of many people [1]. Symptoms of stress, anxiety, and depression significantly increased, while sleep quality and life satisfaction worsened during the successive waves of the pandemic [2–4]. Additionally, an increase in unhealthy lifestyles was observed in Italian adults, although they simultaneously presented a good level of knowledge about coronavirus prevention [5]. Vaccines 2022, 10, 1334. https://doi.org/10.3390/vaccines10081334 https://www.mdpi.com/journal/vaccines