evidence: Specifically, these claims allude to SV40, which stands for Simian Virus 40, a naturally occurring DNA virus originating with monkeys. In the 1960s, some polio vaccines were found to be contaminated with infectious SV40 virus, exposing those receiving the contaminated vaccines to infectious virus. Infectious SV40 virus is not in the Pfizer-BioNTech COVID-19 vaccine. To make the spike mRNA in the COVID-19 vaccine, plasmid DNA is used as a building block, or what is called starting material. Non-infectious fractions of a SV40 sequence are present in the starting material used by Pfizer and BioNTech. The DNA starting material does not contain oncogenes, which are genes that may have the potential to cause cancer. Many vaccines contain small amounts of DNA, otherwise known as residual DNA, for which regulatory authorities have established limits. As is required for all vaccines, the amount of residual DNA present in the Pfizer-BioNTech COVID-19 vaccine is within the amount permitted by standard regulatory guidance. [...] - How to Address COVID-19 Vaccine Misinformation. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/covid-19/health-departments/addressing-vaccine-misinformation.html. Updated November 3, 2021. Accessed April 19, 2023. - Myths and Facts about COVID-19 Vaccines. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/facts.html. Last Updated February 16, 2023. Accessed April 19, 2023.