EDN1 and COVID-19: In the analysis stratified by prior COVID-19 exposure (Fig 2), ET-1 was elevated post-vaccination in both prior and no prior COVID-19 groups, although this increase was not sustained in the prior COVID-19 group post-dose 2.Lastly, a mild post-dose 1 increase (p = 0.027) was observed for PAI only in the prior COVID-19 group.