let's dive in the meat of the matter concerning unknown long term side effect for experimental mRNA "vaccines" and why vaccines for SARS and MERS have never been successful. key words are pathogenic priming and autoimmune disease.
decades of trying without success in animal trials for mRNA gene therapies. lab animals after mRNA jab would successfully generate desired antibodies. months later after being exposed to virus, trial animals would develop vaccine induced autoimmune disease, where the body would attack itself resulting in death.
Pathogenic priming likely contributes to serious and critical illness and mortality in COVID-19 via autoimmunity
Homology between human and viral proteins is an established factor in viral- or vaccine-induced autoimmunity. Failure of SARS and MERS vaccines in animal trials involved pathogenesis consistent with an immunological priming that could involve autoimmunity in lung tissues due to previous exposure to the SARS and MERS spike protein. Exposure pathogenesis to SARS-CoV-2 in COVID-19 likely will lead to similar outcomes. Immunogenic peptides in viruses or bacteria that match human proteins are good candidates for pathogenic priming peptides (similar to the more diffuse idea of "immune enhancement").