What is the difference in the effect on the body of preventive vaccinations and therapeutic serums?

Vaccination is the introduction of weakened microorganisms into the body. When they are introduced into the human body, an immune reaction begins: microorganisms are foreign bodies, antibodies begin to be produced against them, which quickly destroy weakened microorganisms. With the subsequent ingress of such microorganisms into the human body, ready-made antibodies are in the human body.

Serum differs from vaccination in that it contains ready-made antibodies, the body does not have to produce them itself.