Misinformation has emerged as a major societal threat in the recent years in general; specifically in the context of the COVID-19 pandemic, it wrecked havoc, for instance, by fuelling vaccine hesitancy. Cost-effective, scalable solutions for combating misinformation are the need of the hour. This work explores how existing information obtained from social media and augmented with more curated fact-checked data repositories can be harnessed to facilitate automated rebuttal of misinformation at scale. While the ideas herein may be generalized and reapplied in the broader context of misinformation mitigation fusing a multitude of information sources and catering to a spectrum of social media platforms and audience in diverse languages, this work serves as a proof of concept, and is confined in its scope to only rebuttal of (English) tweets, and in the specific context of misinformation regarding COVID-19 vaccination.