This study, using a virus-free mouse model, explores the pathogenic roles and novel mechanism of action of certain antibodies specific to the spike proteins of highly pathogenic coronaviruses such as the COVID-19 and the SARS-CoV viruses. These pathogenic antibodies, induced during a highly pathogenic infection such as the COVID-19 infection, target and bind to host vulnerable cells or tissues such as damaged lung epithelium cells, initiate a persistent self-attack immune response, and lead to serious conditions including ARDS, cytokine storms, and death. Moreover, the pathogenic antibodies may also be responsible for infection-related autoimmune diseases, including those experienced by COVID-19 long haulers. Furthermore, the pathogenic antibodies can bind to the unmatured fetal tissues and cause abortions, postpartum labors, still births, and neonatal deaths of pregnant females. Novel clinical interventions, through disrupting the binding of these pathogenic antibodies, can be developed to fight the COVID-19 pandemic. In addition, the new concept explored by this study may be applicable to other infectious diseases, such as the highly pathogenic influenza infections.