DNA, RNA contaminants
[2012 Sept] Fragments of Foreign DNA and Other Substances From Vaccines Found in Disabled and Dying Children by Christina England
[2012 Sept] Unveiling the Culprit – Is Foreign DNA Contamination the Autistic Villain behind Biologic Vaccine Injuries? By Leslie Carol Botha
Genetically engineered vaccines 'Inherently unpredictable and possibly dangerous'
There is the problem of DNA & RNA contamination of vaccines