evidence: While certain vaccines are produced using fetal tissue cell lines, these cells are not included with the vaccine and regulations for vaccine safety ensure that only trace amounts of fragmented DNA remain in vaccines. It is not possible for vaccines to contain the entire genetic code for a human or cancer genes. Furthermore, people undergo much higher levels of exposure to foreign DNA and/or cells in their everyday lives (e.g. through food) than they do through vaccines, so there is no cause for concern about the minuscule level of DNA fragments in vaccines.