Asystole
#19,097
(Spoiler alert: They didn't find any)
Long before the first COVID vaccine was rolled out to the public (Dec 2020) we were seeing evidence that SARS-CoV-2 infection was driving a sharp spike in sudden cardiac deaths.
In early April 2020, the NYC Fire Department reported a 400% increase in sudden cardiac arrest death calls beginning in late March (see NBC affiliate Massive Spike in NYC ‘Cardiac Arrest’ Deaths Seen as Sign of COVID-19 Under counting).
Since then, the evidence of serious cardiac damage from COVID infection has only increased (see European Society of Cardiology: Major Consensus Statement Released on Long-Term Cardiovascular Impact of COVID Infection).
Yet somehow, the COVID vaccine has been made the villain by countless internet influencers, conspiracy theorists, and clickbait-driven social media accounts. As a result, today COVID infection is treated as trivial by most of the public, while the vaccine is largely shunned.
While no vaccine can claim to be 100% safe in 100% of the population, serious side effects from the COVID vaccine remain rare, and vaccination has been shown to reduce both deaths and disability from COVID (see ECDC Rapid Review: Does COVID-19 Vaccination Reduce the Risk and Duration of Post COVID-19 Condition?).
Meanwhile, COVID still kills tens of thousands of Americans each each year (see EID Journal: Thrombotic Events and Stroke in the Year After COVID-19 or Other Acute Respiratory Infection). But we no longer count or report COVID deaths, so few take notice.
Instead, social media seems to focus on every young sudden cardiac death, and tries to link it to receipt of the COVID vaccine.
While I doubt any amount of scientific evidence is going to sway public opinion, we've another study which finds no credible link between receipt of the COVID vaccine and sudden cardiac death.
They did, however, find a strong link between recent COVID infection and an increased risk of sudden cardiac death. They authors reported:
A documented positive SARS-CoV-2 PCR test within 90 days of the index date was associated with higher odds of death (aOR = 2.36; 95%CI [1.84,3.02]; p<0.001), while a positive SARS-CoV-2 PCR test greater than 90 days before the index date was associated with lower odds of death (aOR = 0.83; 95%CI [0.72,0.95]; p=0.006).
I've reproduced the author's summary below. Follow the link to read it in its entirety. I'll have a bit more after the break.
Husam Abdel-Qadir ,Hardil Anup Bhatt ,Sarah Swayze,Michael Paterson,Dennis T. Ko,David N. Juurlink,Jeffrey C. Kwong
Published: March 19, 2026
https://doi.org/10.1371/journal.pmed.1004924
Background
COVID-19 vaccines can cause rare but serious adverse events such as myocarditis and immune thrombotic thrombocytopenia. Despite a lack of strong evidence, concerns have been expressed that COVID-19 vaccination might lead to sudden death in younger healthy adults. We studied the association between COVID-19 vaccination and sudden death in apparently healthy people aged 12–50 years.
Methods and findings
We conducted a population-based case-control study using linked administrative datasets of residents of Ontario, Canada who were alive as of April 1, 2021. We excluded individuals aged >50 years and those with documented cardiovascular disease, mental illness, or diseases that predispose to adverse outcomes from COVID-19. We defined cases as those with out-of-hospital death, or death within 24 hours of presentation to hospital with a final diagnosis of cardiac arrest between April 1, 2021 and June 30, 2023. We matched each case with five controls on age, sex, region of residence, and neighborhood income quintile. We used conditional logistic regression to assess the association between sudden death and previous COVID-19 vaccination after adjusting for multiple potential confounders (positive severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] tests, number of SARS-CoV-2 polymerase chain reaction (PCR) tests, influenza vaccination, common comorbidities). Sensitivity analyses were conducted with different definitions of the exposure and subsets of cases (with their matched controls). Another sensitivity analysis utilized a modified self-controlled case series (SCCS) of vaccinated individuals meeting the case definition during the study period with up to three doses of any COVID-19 vaccine.
Of 6,365,451 eligible individuals, we identified 4,963 (0.08%) cases meeting our definition of sudden death (median age 36 years, 74.4% male). In the primary analysis, COVID-19 vaccination was associated with a lower risk of sudden death (adjusted odds ratio [aOR] = 0.57; 95% confidence interval (CI) [0.53,0.61]; p < 0.001). The findings were consistent for COVID-19 vaccination within six weeks before death (aOR = 0.63; 95%CI [0.55,0.72]; p < 0.001) and in sensitivity analyses limited to people aged <40 years (aOR = 0.53; 95%CI [0.48,0.58]; p < 0.001), those who died in hospital or in the emergency department (aOR = 0.71; 95%CI [0.55,0.91]; p = 0.006), and after exclusion of opioid-related deaths (aOR = 0.57; 95%CI [0.51,0.64]; p < 0.001).
The SCCS sensitivity analysis showed no significant difference in the rate of sudden death in the 6 weeks following first (relative incidence (RI) 0.87; 95%CI [0.54,1.40]; p = 0.57), second (RI 0.94; 95%CI [0.57,1.57]; p = 0.82), or third (RI 0.87; 95%CI [0.37,2.05]; p = 0.10) dose of the COVID-19 vaccine. Study limitations include the inability to confirm the cause of out-of-hospital deaths and residual confounding due to differences in health-seeking behaviors for the case-control analysis.
Conclusions
These findings do not support the hypothesis that COVID-19 vaccines increase the risk of sudden cardiac death in young healthy adults.
Author summary
Why was this study done?
COVID-19 vaccines were received by a large segment of the population as part of the public health response to the pandemic
There are emerging concerns that COVID-19 vaccines are responsible for sudden death in younger healthy individuals despite a lack of evidence to support this claim
What did the researchers do and find?
A case-control study was conducted involving Ontario residents aged 12–50 years without documented comorbidities predisposing to premature death between April 1, 2021 and June 30, 2023 to examine the association between COVID-19 vaccination and sudden death
The primary outcome was sudden death; the exposure of interest was any COVID-19 vaccination
Among 6,365,451 eligible individuals, 4,806 cases who experienced sudden death were matched to 24,030 controls who were alive on the date of sudden death for each corresponding case
Receipt of COVID-19 vaccination was not associated with increased odds of sudden death
What do these findings mean?
These findings do not support the hypothesis that COVID-19 vaccines increase the risk of sudden cardiac death in younger healthy adults
A limitation of this study was the inability to confirm the cause of out-of-hospital deaths
Three months ago, in WHO Statement: COVID-19 Still Causes Severe Disease & Renewed Vaccination Recommendations, we looked at the ongoing legacy of COVID infection, and yet another plea for the public to protect themselves.
In 2025, we also looked at a number of studies which continue to show long-term impacts from (even mild) COVID infection. A few of many include:
EHJ: Accelerated Vascular Ageing After COVID-19 Infection: The CARTESIAN Study
