https://www.midwesterndoctor.com/p/yale-proved-covid-vax-injury-exists?r=4t5cs3&utm_campaign=post&utm_medium=web&showWelcomeOnShare=false
For example, the spike protein was the most reactive (immunogenic) part of the virus and necessary for SARS to infect cells, so it was an ideal vaccine target. However, it was also a terrible antigen to chose as:

•The spike protein had a significant overlap with human tissues so it was likely to trigger autoimmunity if produced throughout the body.

•The spike protein was highly toxic, so if it was mass produced within the body, it likely would injure the recipient.

•It was a rapidly mutating part of the virus, which guaranteed the circulating spike protein would quick evolve into a variant the vaccine did not work against it—leading to the remarkable situation where we mandated a vaccine for an extinct virus (which, in turn, caused those vaccinated to become more likely to catch COVID-19 as their immune systems were continually primed to respond to a different virus from that they were exposed to)—something best demonstrated by the Cleveland Clinic’s study of 51,011 people):