The mRNA and DNA injections (Moderna, Pfizer, and Johnson&Johnson) consist of genetic particles which invade your body and trick some of your cells into becoming spike protein factories. IMO, the “off switch” on that process doesn’t seem to work very well.
The Novoavax injection consists of spike protein molecules bound up in groups of three. The amount of spike protein to which you would be exposed is limited, and your body isn’t being abused as a spike protein factory.
In both cases, however, any immune response you might generate is specific to those spike proteins only ...
The development and testing of all three genetic material injections is tainted by the use of abortion-derived cell lines. I am unclear, but Novavax appears at first glance to be free of the abortion connection.