At the beginning of the COVID-19 pandemic, fears grew that making vaccination
a political (instead of public health) issue may impact the efficacy of this
life-saving intervention, spurring the spread of vaccine-hesitant content. In
this study, we examine whether there is a relationship between the political
interest of social media users and their exposure to vaccine-hesitant content
on Twitter. We focus on 17 European countries using a multilingual,
longitudinal dataset of tweets spanning the period before COVID, up to the
vaccine roll-out. We find that, in most countries, users' exposure to
vaccine-hesitant content is the highest in the early months of the pandemic,
around the time of greatest scientific uncertainty. Further, users who follow
politicians from right-wing parties, and those associated with authoritarian or
anti-EU stances are more likely to be exposed to vaccine-hesitant content,
whereas those following left-wing politicians, more pro-EU or liberal parties,
are less likely to encounter it. Somewhat surprisingly, politicians did not
play an outsized role in the vaccine debates of their countries, receiving a
similar number of retweets as other similarly popular users. This systematic,
multi-country, longitudinal investigation of the connection of politics with
vaccine hesitancy has important implications for public health policy and
communication.Comment: 15 pages, 11 figure