THE OLD GUARDIAN
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Health Canada’s internal documents show a myocarditis signal was detected in February 2021, confirmed as a probable link by May, and present in 657 Canadian cases by June 2022. The public was told something different.
By Chris Allen | The Old Guardian | September 2026
Primary source: ATI Release A-2025-001410, Health Canada, July 15, 2026
On February 15, 2021, Israel’s Ministry of Health flagged something to Pfizer. Eight weeks after the world’s most aggressive vaccine rollout began, Israeli health officials had noticed a pattern in young men. They called it myocarditis -- inflammation of the heart muscle. They believed the vaccine was connected. They wanted answers.
In Ottawa, Health Canada was listening.
What happened over the next four months -- what regulators concluded internally, what they told Pfizer, what they told each other, and what they told the Canadian public -- is now documented in 2,460 pages of internal Health Canada pharmacovigilance records obtained by The Old Guardian under federal Access to Information request A-2025-001410.
The documents reveal a gap. Not a conspiracy. Not a cover-up in the dramatic sense. Something more bureaucratic and in some ways more troubling: a documented difference between the strength of what regulators knew internally and the strength of what they communicated publicly, on a question that affected millions of Canadians who were rolling up their sleeves and trusting that the full picture was being shared with them.
It was not.
February to May 2021: What the Internal Record Shows
The myocarditis signal moved quickly through the regulatory system once Israel raised it. According to internal Health Canada documents, Pfizer was formally notified of the Israeli concern on February 15, 2021. Health Canada began its own internal review.
By May 15, 2021 -- three months after the Israeli flag -- Pfizer provided Health Canada with a cumulative global safety review of the myocarditis and pericarditis signal. The numbers in that review were significant. As of that date, 108 myocarditis cases and 92 pericarditis cases had been reported in the post-authorization database globally. Three deaths were recorded in the case series.
Seventy percent of the myocarditis cases occurred within seven days of the second dose. The pattern was consistent: young males, second dose, within a week.
Health Canada’s internal assessment concluded: ‘A possible link between the second vaccine dose and the onset of myocarditis among young men aged 16 to 30.’
That conclusion -- a possible link -- was dated May 2021. It was documented in Health Canada’s internal Summary Monthly Safety Report review. It was not a fringe concern from an anti-vaccine researcher. It was the working assessment of Canada’s federal drug regulator, derived from its own review of Pfizer’s global safety data.
Israel had already confirmed a rate higher than background in young males. Health Canada’s internal reviewers agreed the signal was real enough to characterize as a possible causal relationship with the second dose.
Source: ATI Release A-2025-001410, Health Canada internal SMSR review, May 2021. Page 62.
June 3, 2021: What the Public Was Told
On June 3, 2021 -- nineteen days after Health Canada’s internal reviewers had documented a possible link between the vaccine and myocarditis in young men -- the Public Health Agency of Canada and Health Canada issued a communique to health practitioners across Canada.
The communique stated that ‘no clear association has been established between myocarditis/pericarditis and mRNA vaccines, and to date, no regulatory action has been taken in Canada or internationally.’
That statement was technically accurate in a narrow regulatory sense. A possible link documented in an internal review is not the same as a formally established causal association. Health Canada had not yet issued a formal advisory. No regulatory action had been formally taken.
But consider what practitioners reading that communique on June 3 would have understood: that the relationship between myocarditis and mRNA vaccines was unclear, that it had not been established, that no action had been taken.
What they were not told: that Health Canada’s own internal reviewers had, nineteen days earlier, characterized the relationship as a possible link. That 108 myocarditis cases and 92 pericarditis cases had been recorded globally. That three deaths were in the case series. That 70 percent of cases occurred within seven days of the second dose in young males.
The public language and the internal language described the same signal in materially different terms.
Source: Health Canada / PHAC communique to health practitioners, June 3, 2021. ATI Release A-2025-001410, page 62.
June 25, 2021: The Advisement Letter
Ten days after the June 3 communique characterized the myocarditis relationship as unclear, Health Canada issued a formal Advisement Letter to Pfizer on June 25, 2021. The letter was triggered by what the internal BBRS Signal Tracking document describes as ‘local and international signal’ on myocarditis and pericarditis.
The advisement letter is significant for two reasons. First, it confirms that Health Canada had moved from internal assessment to formal regulatory action within weeks of the May 15 cumulative review. Second, it establishes a precise institutional timeline: Health Canada knew enough to formally advise Pfizer on June 25, but the public communique on June 3 had characterized the signal as unclear.
The sequence matters. The internal clock was running faster than the public clock.
Source: ATI Release A-2025-001410, BBRS Signal Tracking document 2020-2023, June 25, 2021 entry.
The Bell’s Palsy Parallel: A Documented Negotiation
The myocarditis story does not stand alone in these documents. Running parallel to it is the Bell’s Palsy signal -- facial paralysis cases following vaccination -- which illustrates how the relationship between Health Canada and Pfizer operated in practice when a safety signal was contested.
By the fifth and sixth Summary Monthly Safety Report review periods, 434 serious facial paralysis cases had been recorded in a single reporting interval. Health Canada formally disagreed with Pfizer’s assessment that this signal could be closed. The internal documents show Health Canada requested that Pfizer update the product monograph -- the label -- to reflect the facial paralysis signal.
Pfizer resisted including it in the clinical trial section of the product monograph. The internal documents record this disagreement explicitly. Health Canada’s position, documented in writing: ‘Health Canada’s position remains the same and the need for further risk mitigation will be discussed with our pre-market colleagues.’
This is not a regulator passively accepting whatever a manufacturer provided. Health Canada pushed back. The negotiation is documented. What is also documented is that the resolution of that negotiation -- what ultimately appeared on the label, and when -- took place in a process that the public had no visibility into.
Source: ATI Release A-2025-001410, SMSR review pages 62-63. BBRS Signal Tracking document, July 12-14, 2021 entries.
By June 2022: 657 Canadian Cases
Health Canada’s internal pharmacovigilance review dated June 24, 2022 provides the most comprehensive Canadian-specific adverse event data in the entire ATI release.
As of that date, across 58,112,512 Comirnaty doses administered in Canada, Health Canada’s internal tracking recorded 657 confirmed myocarditis and pericarditis cases in Canada for the Pfizer vaccine specifically.
To put that number in context: this is not a VAERS-style passive surveillance figure where anyone can submit a report. This is Health Canada’s own internal count of confirmed cases from its pharmacovigilance monitoring -- the most rigorous counting methodology available in Canada’s regulatory system.
657 confirmed Canadian myocarditis and pericarditis cases. Three deaths in the global case series. A signal detected in February 2021, internally characterized as a possible link by May 2021, formally acted upon in June 2021.
The public communication during this same period consistently used language like ‘rare,’ ‘mild,’ and ‘resolves quickly.’ Those characterizations may have been accurate on average. But ‘rare’ for an individual case is not the same as 657 confirmed Canadian cases in a regulatory database that the public had no direct access to.
Source: ATI Release A-2025-001410, Health Canada internal pharmacovigilance review, June 24, 2022. Page 198.
The Ad-Hoc Review and the Benefits-Outweigh-Risks Conclusion
The ATI documents contain a dedicated ad-hoc myocarditis review memo produced by Health Canada’s internal reviewers. The memo’s conclusion is the one that became Health Canada’s public position: the benefits of vaccination outweigh the risks of myocarditis.
That conclusion may well be correct. The evidence on COVID severity, hospitalization rates, and vaccine effectiveness in reducing both -- particularly in the early pandemic waves -- supports the benefits side of that ledger for most age groups.
But the memo reaches that conclusion while simultaneously documenting three deaths in the myocarditis case series, a 70 percent rate of cases within seven days of second dose in young males, and an Israeli confirmation of a rate higher than background.
The question this document raises is not whether the conclusion was wrong. The question is whether Canadians who were being asked to receive a second dose -- particularly young males between 16 and 30 -- were given the same information that Health Canada’s internal reviewers were working from when they reached that conclusion.
The internal memo had the numbers. The public advisories had the conclusion.
Source: ATI Release A-2025-001410, ad-hoc myocarditis review memo. Page 97.
What This Means
The myocarditis signal was real. Health Canada knew it was real. Health Canada eventually said so publicly -- in language that came later and landed softer than the internal assessment.
The gap documented in these records is not fabricated, not inferred, and not speculative. It is a dateable sequence of internal documents and public communications that used materially different language to describe the same signal at the same time.
February 15, 2021: Israel flags the signal.
May 15, 2021: Health Canada’s internal reviewers conclude ‘possible link.’
June 3, 2021: Health Canada’s public communique says ‘no clear association established.’
June 25, 2021: Health Canada issues a formal advisement letter to Pfizer.
June 2022: 657 confirmed Canadian cases in the internal pharmacovigilance database.
This is not a story about malicious intent. It is a story about institutional communication standards -- what regulators owe the public they serve when the internal picture and the public picture diverge.
657 Canadians with confirmed myocarditis or pericarditis in Health Canada’s own database. Each of them made a decision about a second dose while the public language said no clear association had been established. Each of them deserved to know what Health Canada’s internal reviewers already knew.
The internal memo had the numbers. The public advisories had the conclusion. Canadians were given one but not the other.
Editor’s Notes and Primary Sources
All findings in this piece are drawn directly from ATI Release A-2025-001410, a 2,460-page PDF and 81 Excel files released by Health Canada to The Old Guardian on July 15, 2026, under the federal Access to Information Act. The release covers Health Canada’s internal COVID-19 vaccine pharmacovigilance records from 2020 through 2023.
Specific documents cited in this piece:
ATI p.62
Internal SMSR review documenting Israel signal (Feb 15, 2021), Pfizer cumulative review (May 15, 2021), Health Canada internal conclusion of ‘possible link,’ 70% within 7 days of second dose, three deaths in case series.
ATI p.62-63
Bell’s Palsy/facial paralysis signal -- 434 serious cases in one reporting interval, documented disagreement between Health Canada and Pfizer on signal closure and label language.
ATI p.97
Ad-hoc myocarditis review memo concluding ‘benefits outweigh risks’ -- reached while three deaths were in the case series.
ATI p.198
Health Canada internal pharmacovigilance review, June 24, 2022 -- 657 confirmed myocarditis/pericarditis cases in Canada for Comirnaty across 58.1 million doses.
BBRS Signal Tracking (ATI Excel file)
Internal project tracking log (2020-2023) -- June 25, 2021 advisement letter to Pfizer on myocarditis/pericarditis; July 12-14, 2021 Bell’s Palsy memo and advisement letter entries documented.
Public record
Health Canada / PHAC communique to health practitioners, June 3, 2021 -- ‘no clear association has been established between myocarditis/pericarditis and mRNA vaccines.’
The Old Guardian’s full series What They Knew examines Health Canada’s internal COVID-19 vaccine pharmacovigilance records across six parts, publishing in September 2026 in conjunction with the Allison Inquiry hearings at Parliament Hill.
If you or a family member experienced a serious adverse event following COVID-19 vaccination, contact The Old Guardian at tips@theoldguardian.ca. Source confidentiality is protected. Verification is required.
The Old Guardian | theoldguardian.ca | tips@theoldguardian.ca | ATI File: A-2025-001410