Social media are increasingly envisioned by public health authorities as a new promising arena for public engagement. Against this backdrop, this article attends to how citizens confirm, debate and resist governmental framings of health information online. By drawing upon STS and affect theory, it centers on the digital mediation of feelings on a Facebook engagement site for HPV vaccination. While the public authorities framed HPV vaccination as a matter of love and fear, a wide register of positive and negative feelings were mediated on the site. The article proposes the notion of ‘digitalised literary devices’ to analyse how mundane literary habits, such as the use of punctuation, online have been transformed to digital devices that, for instance, mediate public feelings. By conceptualizing public engagement as ‘civic intensities’, it shows how digital devices, such as digitalised literary devices, mediate and intensify public feelings of engagement.