Trust keeps anger at bay: Germany’s experience with the measles vaccine mandate – a longitudinal survey study

Vaccine mandates can increase uptake, yet their psychological effects remain underexplored. Psychological reactance theory suggests that mandates may prompt resistance and reduce acceptance of voluntary vaccination. We used multilevel modelling to examine changes in reactance and attitudes toward the measles vaccine mandate introduced in Germany in 2020, the extent to which reactance prompted attempts at freedom restoration, and the role of trust in mandate acceptance. An initial sample of 6901 participants was followed across six waves. Reactance levels were low but stable over time, while attitudes toward the mandate became increasingly negative. Higher trust was associated with lower reactance and more positive attitudes. Importantly, higher initial reactance predicted a lower likelihood of later uptake of voluntary vaccines. These findings suggest that reactance to public health policies may persist rather than fade and can shape downstream health behavior. Building trust and ensuring effective enforcement may help legitimize mandates and mitigate opposition.