Health Canada Won’t Say If It Asked Pfizer to Remove SV40 Sequence in COVID Shots

Health Canada Won’t Say If It Asked Pfizer to Remove SV40 Sequence in COVID Shots
A sign is displayed in front of Health Canada headquarters in Ottawa on Jan. 3, 2014. (The Canadian Press/Sean Kilpatrick
Noé Chartier

Health Canada has refused on several occasions to confirm whether it made a request to Pfizer for the removal of the Simian Virus 40 (SV40) DNA regulatory sequence in its COVID-19 vaccines.

“Unfortunately we are unable to provide a response without disclosing the redacted content of the message, which is proprietary,” Health Canada spokesperson Anna Maddison told The Epoch Times on May 3 when asked about recently released internal emails and documents.

Heavily redacted records released through the access-to-information system detail Health Canada officials’ efforts to “remedy” the SV40 situation and saying Pfizer has been non-committal.

Health Canada says that any request it might have made to Pfizer on the matter would be considered proprietary. The Epoch Times has filed a complaint about the response with the Information Commissioner of Canada..

“Again, Health Canada is unable to share information via a media response that is proprietary and has been exempted under the Access to Information Act,” Ms. Maddison responded on May 8 after a follow-up request. A subsequent call to Ms. Maddison was not returned.

Some of the released correspondence indicates that Pfizer didn’t fulfill some requests made by Health Canada scientists when corresponding on the SV40 issue.

Health Canada was initially not aware of the presence of the SV40 enhancer-promoter in the Pfizer-BioNTech injections almost three years after it first authorized the distribution of the products.

The Epoch Times first contacted Health Canada on July 17, 2023, about DNA impurities in mRNA injections. The earliest apparent date on which Health Canada scientists discussed the matter is July 19, according to available records.

The issue of DNA impurities in mRNA shots was first discovered by genomics expert Kevin McKernan, who published his findings in a scientific preprint in April 2023.
According to the recently released records, a Health Canada official said Pfizer “apparently chose not to” inform national drug regulators about SV40.
The SV40 enhancer-promoter is a piece of biotechnology used to drive gene expression in mammalian cells. Pfizer and Health Canada say it serves no purpose in manufacturing the mRNA product, but this response doesn’t answer why the sequence is present.


After Health Canada found out about the SV40 sequence, it sent its first quality clarifax—a formal request for information—from Pfizer about its new shot for the Omicron XBB.1.5 variant on Aug. 4, 2023.
Health Canada told Pfizer that a sequence analysis of “plasmid [redacted] (XBB1.5) indicates the presence of the regulatory region sequence of Simian Virus (SV40).” The drug regulator asked for justification for the presence of the SV40 regulatory elements, and for Pfizer to provide data on the size of DNA fragments.
The size of fragments is related to the potential for genomic integration. Some scientists have warned about potential related cancer risks. Florida State Surgeon General Dr. Joseph A. Ladapo has called for a halt of mRNA shots over these risks.
Health Canada has previously stated that “any claims that the presence of the SV40 promoter enhancer sequence is linked to an increased risk of cancer are unfounded.”

In a heavily redacted response around Aug. 11, 2023, Pfizer wrote that the “SV40 regulatory elements are not relevant to mRNA production since mammalian cells are not used in this process.”

Pfizer also said that “since the SV40 promoter/enhancer DNA does not contain known oncogenes, infectious agents, or regions that could lead to functional transcripts, the DNA does not present any specific safety concerns.” Pfizer also committed to provide data on the DNA fragments.

Virologist Dr. David Speicher from the University of Guelph says the SV40 enhancer-promoter is only used for integration and transcription in mammalian cells.

“It should not have been in the plasmid as Pfizer was only dealing with a bacterial host,” he told The Epoch Times. “Injection of DNA fragments attached to an SV40 enhancer directly into the cell, as done with lipid nanoparticles, greatly increases the probability of integration compared to DNA vaccines.”

Dr. Speicher said that given there is no compendial pharmacopoeia, or quality standard, for mRNA vaccines, especially those with SV40 regulatory sequences, Health Canada did not know how to handle this situation.


The response from Pfizer on SV40 did not appear to satisfy Health Canada officials entirely, as they proceeded to coordinate with other national drug regulators on the matter and prepared additional clarifax for Pfizer.

Dr. Dean Smith, senior scientific evaluator in Health Canada’s Vaccine Quality Division, started emailing on Aug. 21, 2023, asking to have a “brief chat on SV40” with an undisclosed employee of the European Medicines Agency (EMA).

“This is a [public] topic now and we are approaching the next vaccination season for these vaccines,” wrote Dr. Smith, who wanted the issue to be addressed during a “Cluster meeting” with staff from other national regulating agencies, “just to [begin] to coordinate on that.”

On Aug. 23, Dr. Smith continued his work to coordinate with other national regulators. In an email to an undisclosed U.S. Food and Drugs Administration (FDA) official, he again raised discussing the SV40 issue at a cluster meeting.

Dr. Smith said this could “help inform potential exchanges between Agencies and Pfizer on the SV40 topic, as well as future actions we may collectively consider taking subsequently to encourage Pfizer to remedy the situation prior to a potential fall 2024 COVID-19 vaccine campaign.”

Dr. Smith did not link the desire to “remedy the situation” to health concerns, saying Health Canada did not consider it an “urgent risk topic,” but rather to the potential impact public knowledge of the issue could have on vaccine uptake.

The email from Dr. Smith to the FDA is the first indication in the released records that Health Canada wanted to “remedy” the situation of the SV40 regulatory element in the Pfizer shots.

While Dr. Smith was coordinating with foreign regulators, another Health Canada scientist was preparing a new request for information to Pfizer based on the previous response.

Dr. Tong Wu of Health Canada’s Vaccine Quality Division prepared the new clarifax for Pfizer. “Health Canada is not aware of any peer-reviewed scientific evidence that would raise safety concerns over [large block of redacted text] Please comment,” part of it says.

The clarifax also said Health Canada noted Pfizer’s commitment to provide data on the fragments.

‘Pfizer Didn’t Commit’

Pfizer responded on Aug. 25 to Dr. Wu’s clarifax, although much of the content was redacted in the publicly released document.

A few minutes after Health Canada received the response, Dr. Wu wrote an email to Dr. Smith and other colleagues with the subject line “SV40 sequence - Pfizer’s response” and a single short sentence in the body text: “As expected, Pfizer didn’t commit.”

The Epoch Times asked Health Canada specifically about this email from Dr. Wu and whether it relates to Health Canada asking for the SV40 sequence to be removed and Pfizer not committing. Health Canada refused to answer, saying the information is “proprietary.”

Dr. Smith responded to Dr. Wu’s email by saying that “not all is lost” given the cluster meeting of the previous day with the EMA and FDA.

“At least Pfizer’s reply acknowledges ‘minimal risk’ [redacted],” wrote Dr. Smith. Health Canada relies on information provided by manufacturers to evaluate safety and doesn’t do any testing itself, previous statements from the regulator indicate.

“It will still require FDA and EMA support, but that may still be achievable,” added Dr. Smith.

“And, as you pointed out before your clarifax [went] out, the negative reply supports our need to coordinate with our international partners,” said Dr. Smith. “In the current climate, that is a win for us and thank to you and your team for that!!”

‘Current Climate’

There is no additional information provided about the “current climate” Dr. Smith refers to, but other records point to Health Canada officials’ frustration with Pfizer.

“I agree with [Dr.] Dean [Smith] that we should not tell Pfizer our interaction with EMA and FDA on this (especially they do not seem to care much at this moment). However, we can not say nothing!” wrote Dr. Wu in an Aug. 29 email to Dr. Smith and Dr. Michael Wall, a senior biologist evaluator with Health Canada.

Dr. Wall moments earlier had prepared yet another draft clarifax to send to Pfizer on Aug. 29.

“Health Canada will continue to work with international regulatory partners to achieve harmonisation regarding removal of these sequence elements from the plasmid for future strain changes,” it said about SV40.

The clarifax that Health Canada sent to Pfizer on Aug. 30 is fully redacted and was framed only as a comment that didn’t require a response.

Another Health Canada comment for Pfizer that isn’t redacted and appears in the formal quality review of Pfizer’s Omicron XBB.1.5.5, produced by Dr. Wu on Sept. 5, says “the Sponsor [Pfizer] is reminded of the obligation to report OOS results for on-going stability monitoring of COMIRNATY vaccines.”

In the drug sector, when the results of laboratory tests show the product values are outside the specifications or acceptance criteria, it is said to be Out-of-Specification, or OOS.

Pfizer has not been responding to Epoch Times inquiries on this issue.