EXCLUSIVE: Health Canada Confirms Undisclosed Presence of DNA Sequence in Pfizer Shot

The health regulator says Pfizer did not disclose the presence of the Simian Virus 40 (SV40) DNA sequence in its mRNA COVID-19 vaccine at the time of filing.

A sign is displayed in front of Health Canada headquarters in Ottawa in a file photo. Sean Kilpatrick/The Canadian Press

Health Canada has confirmed the presence of a Simian Virus 40 (SV40) DNA sequence in the Pfizer COVID-19 vaccine, which the manufacturer had not previously disclosed.

There is debate among scientists with regards to the significance of the finding, with some saying the DNA sequence has the potential to cause cancer, and others saying it poses little to no threat.