  Twitter influences political debates. Phenomena like fake news and hate
speech show that political discourse on micro-blogging can become strongly
polarised by algorithmic enforcement of selective perception. Some political
actors actively employ strategies to facilitate polarisation on Twitter, as
past contributions show, via strategies of 'hashjacking'. For the example of
COVID-19 related hashtags and their retweet networks, we examine the case of
partisan accounts of the German far-right party Alternative f\"ur Deutschland
(AfD) and their potential use of 'hashjacking' in May 2020. Our findings
indicate that polarisation of political party hashtags has not changed
significantly in the last two years. We see that right-wing partisans are
actively and effectively polarising the discourse by 'hashjacking' COVID-19
related hashtags, like #CoronaVirusDE or #FlattenTheCurve. This polarisation
strategy is dominated by the activity of a limited set of heavy users. The
results underline the necessity to understand the dynamics of discourse
polarisation, as an active political communication strategy of the far-right,
by only a handful of very active accounts.
