Fig. 1: Effects of scenarios for a hypothetical vaccination campaign (experiment 1).

a–d, The manipulated attributes in this experiment included the severity of the circulating virus variant (decline, escalation, no change; ‘Virus_variant’); the availability of the protein subunit COVID-19 vaccine Novavax or the inactivated whole virus vaccine Valneva in addition to mRNA vaccines (mRNA + inactive, mRNA only; ‘Vaccines’); Omicron adaption (adapted, not adapted; ‘Omicron_adapted’); costs/incentives (a voucher with a value of 500 Euros, cash of the same amount, a fee of 20 Euros for getting vaccinated and the vaccination being free of charge; ‘Incentives’); and motivational campaign messages (‘Motivation’) regarding the protection of the healthcare system (‘Protect_health_system’), the reduction of the risk for a lockdown (‘Risk_lockdown’), the ability to contribute oneself (‘Self_efficacy’), the protection of friends (‘Protect_friends’), the protection of the community (‘Community_spirit’), the reduction of the risk for severe disease (‘Risk_severe_disease’), the risk for being unable to work (‘Risk_unable_to_work’) and the risk of re-infection (‘Risk_re-infection’). We calculated AMCEs. Data are presented as AMCE estimates ± 95% CIs. Exact P values are shown in Supplementary Files 5–8. In total, 6,357 respondents participated in this experiment (Austria: n = 3,187; Italy: n = 3,170).