  This study provides an in-depth analysis of a Twitter dataset around
AstraZeneca COVID vaccine development released as a part of Grand Challenge,
North American Social Network Conference, 2021. In brief, we show: i) the
presence of malicious and low credibility information sources shared on Twitter
messages in multiple languages, ii) the malicious URLs, often in shortened
forms, are increasingly hosted in content delivery networks and shared cloud
hosting infrastructures not only to improve reach but also to avoid being
detected and blocked, iii) potential signs of coordination to promote both
malicious and low credibility URLs on Twitter. We use a null model and several
statistical tests to identify meaningful coordination behavior.
