Natural activity of the human immune system does not include adding Simian-40 DNA to the human body - but the pharmaceutical manufacturers have done that.
Do you have any reliable source that SV40 is being injected into the human body? By "reliable", I mean a source that is published within the medical literature, is catalogued in PubMed and is accepted as reliable by experts in various scientific disciplines?
First, an intact SV40 virus is not present at anywhere along the vaccine production process. The only part of the SV40 that is used is a tiny sequence of DNA whose only function is to signal to the RNA polymerases that here is the beginning of a gene that they need to transcribe (i.e. make an RNA copy). SV40 is widely used in molecular biology.
But what would happen if a tiny piece of SV40 promoter were to enter the human body? It would be destroyed almost immediately. Your body loves to destroy DNA. You have enzymes in your skin, your mucous membranes, your blood, etc., that exist for the sole purpose of destroying foreign DNA. Those DNA destroying enzymes are so prevalent and active that those of us who work with DNA are careful NEVER to touch any tubes, pipettes, etc., with our bare hands. Because we will destroy the DNA in our sample.