Here, educate yourselves - SV-40 is a polyoma virus, which literally means "multiple kinds of tumors".
It is a known human oncogen. Here is what NIH says about it:
"there is a significant excess risk of SV40 associated with human primary brain cancers, primary bone cancers, malignant mesothelioma, and non-Hodgkin's lymphoma"
The polyomavirus simian virus 40 (SV40) is a known oncogenic DNA virus which induces primary brain and bone cancers, malignant mesothelioma, and lymphomas in laboratory animals. Persuasive evidence now indicates that SV40 is causing infections in humans ...
www.ncbi.nlm.nih.gov
JC virus, the one I worked on, is also a polyoma virus. It works differently, has a different mechanism. However they all have something in common, they inhibit the body's natural DNA repair mechanisms.
In the case of SV-40, research has zeroed in on the p53 tumor suppressor protein (it "suppresses" tumors by repairing them). Ordinarily SV-40 is not excessively dangerous for HEALTHY humans, however it can be thoroughly fatal for immune compromised individuals - which includes anyone taking biologicals.
It can be fatal in SEVERAL ways. It attacks mesothelial cells, and it attacks the blood brain barrier. In the case of the JC virus, if the polyoma gets into the brain it's likely fatal, it causes PML which is a progressive leukoencephalopathy.
Polyoma viruses hang out in the kidneys and spleen (and the brain if they get there). They can remain dormant for long periods of time. They are a RISK.