Why did you do it? Reasons for vaccination and non-vaccination among young adults in Serbia

Background: We explored the reasons young people in Serbia give for getting or not getting vaccinated and whether these reasons correspond to the selfish-rational and social norms models of vaccination choices. Methods: 229 participants aged 18–35 (71% women) completed an online survey. In a fictitious disease scenario, n=89 ‘vaccinators’ reported they would definitely/probably get vaccinated, while n=140 ‘nonvaccinators’ would definitely/probably not. They rated a list of reasons for (non-)vaccination (‘completely/somewhat describes my reasons’ indicated endorsement); an open-ended question elicited reasons outside of the two models. Findings: While vaccinators reported not relying on others for protection (46%), non-vaccinators rarely endorsed free-riding (‘many people got vaccinated so I don’t have to’; 19%). What the majority was doing (descriptive norm) was relevant for vaccinators (47%) and they trusted the ‘wisdom of the common man’ (43%); others' behavior was less important for non-vaccinators (25% and 33%, respectively). Weighing personal benefits against risks of vaccination was a common reason for both vaccinators (85%) and non-vaccinators (73%). Vaccinators viewed vaccination as necessary to protect oneself (99%) and others (90%) and as a collective effort to stop the disease (91%). Non-vaccinators believed they did not need vaccination to protect their health (62%). A part of the survey about COVID-19 (n=213) replicated this pattern of results. Discussion: While the reasons stemming from the two theoretical models were less endorsed by non-vaccinators (perhaps due to distrust in vaccine effectiveness), the analysis of open ended responses revealed new reasons (e.g. conspiratorial beliefs). Overall, this study can inform more targeted communication interventions