  Societies worldwide have witnessed growing rifts separating advocates and
opponents of vaccinations and other COVID-19 countermeasures. With the rollout
of vaccination campaigns, German-speaking regions exhibited much lower
vaccination uptake than other European regions. While Austria, Germany, and
Switzerland (the DACH region) caught up over time, it remains unclear which
factors contributed to these changes. Scrutinizing public discourses can help
shed light on the intricacies of vaccine hesitancy and inform policy-makers
tasked with making far-reaching decisions: policies need to effectively curb
the spread of the virus while respecting fundamental civic liberties and
minimizing undesired consequences. This study draws on Twitter data to analyze
the topics prevalent in the public discourse. It further maps the topics to
different phases of the pandemic and policy changes to identify potential
drivers of change in public attention. We use a hybrid pipeline to detect and
analyze vaccination-related tweets using topic modeling, sentiment analysis,
and a minimum of social scientific domain knowledge to analyze the discourse
about vaccinations in the light of the COVID-19 pandemic in the DACH region. We
show that skepticism regarding the severity of the COVID-19 virus and towards
efficacy and safety of vaccines were among the prevalent topics in the
discourse on Twitter but that the most attention was given to debating the
theme of freedom and civic liberties. Especially during later phases of the
pandemic, when implemented policies restricted the freedom of unvaccinated
citizens, increased vaccination uptake could be observed. At the same time,
increasingly negative and polarized sentiments emerge in the discourse. This
suggests that these policies might have effectively attenuated vaccination
hesitancy but were not successfully dispersing citizens' doubts and concerns.
