This was a new concept to me, that of “original antigeneic sin.” Consequent immune response depends a lot upon the original infection. “A narrow-spectrum vaccine with suboptimal antibodies that only recognise the spike protein of the virus and not the "N" or nucleocapsid part of the virus will interfere or trip up the natural immune response. The spike protein will cause B cells in those with the vaccine to learn to produce only spike protein antibodies. These antibodies are slower-acting and less sterilising than the N antibodies, which are faster and more effective.” This is the “original sin,” having a limited immune response due to the way the vaccine is supposed to work. As detailed below, it is one hypothesis advanced to account for the surge in breakthrough covid infections.