Abstract
Government communication is central for raising awareness about policy decisions and influencing citizen behaviour. Social media allows public authorities to involve the population in policy actions via interactive exchanges. This article investigates the link between vaccination-related posts published by government bodies in five Central and Eastern European states on Facebook and citizen engagement during the COVID-19 pandemic. It uses innovative topic modelling and clustering techniques and tests the association between content and engagement. Our study reveals significant differences in social-media engagement across various vaccination communication strategies on Facebook. We found that rational types of content—relying on facts and data—led to the highest levels of citizen engagement.