Mapping the Dutch vaccination debate on Twitter: Identifying communities, narratives, and interactions.

In recent years, vaccination rates in the Netherlands have declined slightly, but steadily. The Dutch National Institute for Public Health and the Environment (RIVM) commissioned a Committee for Vaccine Willingness (VWC) to study the societal context of the decline. One of the societal contexts is the Internet, where audiences discuss vaccination and refer to sources of health-related information of varying quality. Working for the VWC, we have explored the Dutch vaccination debate on Twitter in order to: (1) identify online communities in the vaccination debate, (2) identify vaccine-related narratives; and (3) understand how the online communities interact with each other. We identified seven different communities, including (public) health professionals, writers and journalists, anti-establishment, and international vaccination advocates. The debate is spearheaded by the writers & journalists community, while the health- and anti-establishment communities try to influence it. The health community circulates facts, figures and scientific studies, while negative messages about vaccination - either from a homeopathy or conspiracy perspective - are most prevalent in the anti-establishment. The facts and figures shared by the health community hardly reach other communities, whereas the myths introduced by the anti-establishment do spill over to other communities. Our study provides further evidence that negative perceptions about vaccination might be rooted in a wider sentiment of distrust of traditional institutions. We argue that Dutch health organizations should try to address questions, doubts, and worries among the general audience more actively, and present scientific information in a simpler and more attractive way.