The Claim:
A cardiologist claims that mRNA vaccines contain the SV40 virus, and can therefore cause cancer.
The Facts:
SV40 is a virus found in monkey kidneys that can potentially cause cancer in humans via tumor (T) antigens. Unfortunately, batches of the polio vaccine became contaminated with SV40, and the methods used to inactivate the poliovirus did not reliably inactivate SV40. Importantly, epidemiological studies have found no increased risk of cancer in those who received these vaccines.
Since then, a promoter gene (a DNA sequence that starts RNA transcription) of SV40 has been found to promote a high level of gene expression for producing proteins in mammalian cells and has been used in developing DNA vaccines. The process uses just the promoter gene and not the virus itself or any part of the DNA sequence that encodes for the T antigen of SV40.
Right now, no evidence exists that mRNA COVID vaccines contain SV40 genes, aside from a single paper that has claimed to sequence the SV40 promoter gene from the Pfizer vaccine.
Disclaimer: Science is always evolving and our understanding of these topics may have evolved since this was originally posted. Browse the latest information posted in Just the Facts Topics.
Just the Facts Newsletter:
Correcting this week's disinformation
Sign up to get a weekly look at the latest vaccination facts as we debunk the latest false vaccination claims making the rounds on the internet.