In a recent study, we reported that certain anti-spike antibodies of COVID-19 and SARS-CoV viruses can have a pathogenic effect through binding to sick lung epithelium cells and misleading immune responses to attack self-cells. We termed this new pathogenic mechanism “Antibody Dependent Auto-Attack” (ADAA). This study explores a drug candidate for prevention and treatment of such ADAA-based diseases. The drug candidate is a formulation comprising N-acetylneuraminic acid methyl ester (NANA-Me), an analog of N-acetylneuraminic acid. NANA-Me acts through a unique mechanism of action (MOA) which is repairment of the missing sialic acid on sick lung epithelium cells. This MOA can block the antibodies’ binding to sick cells, which are vulnerable to pathogenic antibodies. Our in vivo data showed that the formulation significantly reduced the sickness and deaths caused by pathogenic anti-spike antibodies. Therefore, the formulation has the potential to prevent and treat the serious conditions caused by pathogenic antibodies during a COVID-19 infection. In addition, the formulation has potential to prevent and treat the adverse reactions of COVID-19 vaccines because the vaccines can induce similar antibodies, including pathogenic antibodies. The formulation will be helpful in increasing the safety of the vaccines without reducing the vaccine’s efficacy. Compared to existing antiviral drugs, the formulation has a unique MOA of targeting receptors, broad spectrum of indications, excellent safety profile, resistance to mutations, and can be easily produced.