Hayashi et al. using an animal model revealed that defective NF-κB1 expression can be involved in the development of autoimmune myocarditis, especially after HBV vaccination, and that spontaneous myocarditis following mRNA-based SARS-CoV-2 vaccines should originate from allergic mechanisms and/or immune complex deposition [67]. Here, NFKB1 is linked to autoimmune myocarditis.