The COVID-19 pandemic has exposed deep political fissures in public discourse. This talk presents findings from comprehensive analyses of COVID-19-related tweets, examining how political polarization manifests in social media discussions on contentious issues like the origins of the virus, masking, stay-at-home orders, and vaccines. Using computational methods, we explore the interplay of moral language, emotional dynamics, and elite influence across the political spectrum. Our research also reveals striking differences in communication strategies between public health experts and pseudo-experts, and introduces a novel framework for quantifying affective polarization. These insights shed light on the evolution of the partisan divides in  attitudes on contentious issues during the pandemic.