JMIR Publications

ABSTRACT

The impact of echo chambers and influential users on information dissemination in social networks is important for health communication to combat vaccine hesitancy. Assessing the temporal development of echo chambers, and the relation that influential users have on their growth, gives insight on effective communication for preventing rise in vaccine hesitancy. In this study, a Taiwanese forum dataset is used, and a multilayer network model is constructed to assess the existence of echo chambers. Each layer represents either pro-vaccination, vaccine hesitant, or anti-vaccination board posts, and their cross-commenting and comment-receiving behaviour is used to measure echo chambering. For understanding the behaviour of influential users – or key nodes – in the network, node degree and PageRank is used, in addition to the conceptualisations of these measurements on a multilevel network. The decreasing homophily between layers over time suggests that there is no existence of echo chambers. Instead, there are increasing cross-cutting exchanges between layers, supporting a “battleground” engagement from both polarised layers on vaccine hesitant boards. When looking at behaviour of hardliners – a type of influential node mostly commenting within their layer – anti-vaccination hardliners are more active in engaging with the vaccine hesitant layer than the pro-vaccination equivalent. When looking at behaviour of high PageRank nodes in a layer, they also mostly engage with the vaccine hesitant layer. The findings suggest that the pro-vaccination layer should increase its efforts to engage with vaccine hesitant individuals. In addition, efforts should be made to target hardliner and influential nodes in the anti-vaccination layer to reduce engagement with the vaccine hesitant layer, preventing sway in the battleground.