Résumé : This research updates early studies on the intention to be vaccinated against the Covid-19 virus among a representative sample of adults in 6 European countries (France, Germany, Italy, Spain, Sweden, and the UK) and differentiated by groups of “acceptors”, “refusers”, and “ hesitant”. The research relies on a set of traditional logistic and more complex classification techniques such as Neural Networks and Random Forest techniques to determine common predictors of vaccination preferences. The findings highlight that socio-demographics are not a reliable measure of vaccination propensity, after one controls for different risk perceptions, and illustrate the key role of institutional and peer trust for vaccination success. Policymakers must build vaccine promotion techniques differentiated according to “acceptors”, “refusers”, and “ hesitant”, while restoring much larger trust in their actions upfront since the pandemics if one wishes the vaccination coverage to close part of the gap to the level of herd immunity.