Question explored with the scientific record
Covid shot and afib
The short version: case reports and animal studies show a plausible mechanism for COVID-19 vaccine-triggered atrial fibrillation, but the one large population study found no statistically significant association after adjustment.
The evidence here is a mix of case reports and one large Korean cohort study. The case reports describe patients developing AF within days of various COVID-19 vaccines [1, 2, 3]. Some had clear triggers like vaccine-induced hyperthyroidism [3] or pericarditis [2]. A mouse study showed that the spike protein alone, even without the virus, causes inflammatory damage to heart tissue and increases atrial arrhythmias [10]. That is a plausible mechanism: spike-induced inflammation disrupts the electrical connections between heart cells.
The Korean study of over 2 million vaccinated people compared to 334,000 unvaccinated found that after adjusting for age, sex, and health conditions, the association between vaccination and new-onset AF was not statistically significant [4]. The same study did find a clear increase in myocarditis, especially in younger males with mRNA vaccines [4]. A separate VAERS analysis found that arrhythmia reports were highest for the Pfizer COVID-19 vaccine, at 1,442 reports per 100,000 total VAERS reports [11]. But VAERS is a passive system that captures only a fraction of real events and cannot prove causation.
| Outcome | Vaccinated vs Unvaccinated (Korean cohort) | Source |
|---|---|---|
| Atrial fibrillation | No significant association after adjustment | [4] |
| Myocarditis | HR ~3.92 (elevated, especially mRNA in young males) | [4] |
| Pulmonary thromboembolism | HR ~0.55 (lower in vaccinated) | [4] |
The case reports establish that AF can occur after vaccination in susceptible individuals, and the mouse study gives a mechanism. But the only large controlled study found no population-level excess. The evidence is not strong enough to say the vaccines cause AF in the general population, but it is also not strong enough to rule it out for individuals with underlying risk factors like thyroid disease or a history of pericarditis.
My call: the evidence for a causal link between COVID-19 vaccines and new-onset AF is weak at the population level but plausible in specific individuals with predisposing conditions.
Sources examined 24
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Atrial Fibrillation After mRNA-1273 SARS-CoV-2 Vaccination: Case Report with Literature Review
This case report describes a 55-year-old woman who developed atrial fibrillation three days after receiving the mRNA-1273 COVID-19 vaccine, highlighting potential cardiac complications associated with vaccination.
DOI: 10.2147/RMHP.S402007 -
Atrial fibrillation as a precursor of mRNA-1273 SARS-CoV-2 vaccine-induced pericarditis
This study describes a case of a healthy 49-year-old male who developed atrial fibrillation and subsequent pericarditis following the mRNA-1273 SARS-CoV-2 vaccination, highlighting the potential cardiac complications associated with COVID-19 vaccinations.
DOI: 10.1007/s43678-021-00250-4 -
A Case of Exacerbation of Subclinical Hyperthyroidism after First Administration of BNT162b2 mRNA COVID-19 Vaccine
This case report describes a 64-year-old Japanese woman who developed exacerbation of subclinical hyperthyroidism, complicated by atrial fibrillation and heart failure, following her first dose of the BNT162b2 mRNA COVID-19 vaccine.
DOI: 10.3390/vaccines9101108 -
The early impact of COVID-19 vaccines on major events in cardiac, pulmonary, and thromboembolic disease: a population-based study
A large population-based retrospective cohort study in Seoul, Korea, comparing short-term (1 week to 3 months) incidence of myocarditis, MI, atrial fibrillation, interstitial lung disease, pulmonary thromboembolism, deep vein thrombosis, and cerebrovascular disease between adult…
DOI: 10.3904/kjim.2025.056 -
Risk Factors for COVID-19–Related Hospitalization and Death in Patients With Cancer
A large prospective cohort of 1572 adults with cancer and a first positive SARS-CoV-2 test identifies factors linked to COVID-19–related hospitalization and death, showing chemotherapy and thrombotic history increase risk while vaccination reduces it, and documenting substantial…
DOI: 10.1001/jamaoncol.2025.2010 -
Rapidly progressive IgA nephropathy with membranoproliferative glomerulonephritis-like lesions in an elderly man following the third dose of an mRNA COVID-19 vaccine: a case report
This case report describes a 77-year-old man who developed rapidly progressive IgA nephropathy with membranoproliferative glomerulonephritis-like lesions following the third dose of an mRNA COVID-19 vaccine, highlighting potential renal complications associated with COVID-19 vac…
DOI: 10.1186/s12882-023-03169-3 -
Immune thrombocytopenia associated with COVID-19 mRNA vaccine tozinameran – a clinical case and global pharmacovigilance data
This study reports a clinical case of immune thrombocytopenia (ITP) in a 77-year-old man following the first dose of the COVID-19 mRNA vaccine tozinameran, along with an analysis of global pharmacovigilance data indicating a higher than expected incidence of ITP post-vaccination.
DOI: 10.4414/smw.2021.w30084 -
Retinal Vein Occlusion Following Two Doses of mRNA-1237 (Moderna) Immunization for SARS-Cov-2: A Case Report
This case report describes a 74-year-old woman who experienced a hemispheric retinal vein occlusion 48 hours after receiving the second dose of the mRNA-1237 (Moderna) vaccine for SARS-CoV-2, highlighting the need for further research into potential ocular adverse events associa…
DOI: 10.1007/s40123-021-00441-3 -
Genetic proxies for clinical traits are associated with increased risk of severe COVID-19
This study investigates the integration of polygenic risk scores (PRS) with traditional risk factors to assess their association with severe COVID-19 outcomes in a large cohort from the UK Biobank, revealing that certain PRS remain significant predictors even after adjusting for…
DOI: 10.1038/s41598-025-86260-z -
SARS-CoV-2 spike protein-induced inflammation underlies proarrhythmia in COVID-19
This study demonstrates that inflammatory signaling triggered by SARS-CoV-2 spike protein, even in the absence of direct viral infection of the heart, induces vascular leak and intercalated disc remodeling in mice, increasing atrial arrhythmia burden and suggesting spike-induced…
DOI: 10.1038/s41598-025-12807-9 -
Cardiac adverse events post-vaccination
A VAERS-based retrospective analysis identifies multiple cardiac adverse-event associations with vaccines, notably bradycardia/cardiac arrest in infants and myocarditis/pericarditis across several vaccines, and posits histamine/immune signaling–related etiologies with mitigation…
DOI: 10.36922/bh.5747 -
New-onset Diabetes Patients Need Pancreatic Cancer Screening?
This study investigates the characteristics of new-onset diabetes patients with pancreatic cancer and proposes screening criteria based on age, weight loss, and body mass index to identify those at higher risk for pancreatic cancer.
DOI: 10.1097/MCG.0b013e318238348c -
Application of machine learning algorithms in predicting new onset hypertension: a study based on the China Health and Nutrition Survey
This study utilizes machine learning algorithms to predict new onset hypertension based on data from the China Health and Nutrition Survey, identifying key risk factors and demonstrating the superior performance of the AMFormer model compared to traditional methods.
DOI: 10.1265/ehpm.24-00270 -
Association of the body roundness index with new-onset cardiovascular disease in middle-aged and older adults with and without diabetes: evidence from the China Health and Retirement Longitudinal Study
This study investigates the association between the body roundness index (BRI) and new-onset cardiovascular disease (CVD) in middle-aged and older adults with and without diabetes, revealing a significant positive correlation particularly in non-diabetic individuals.
DOI: 10.1186/s13098-025-01705-9 -
Effect of Pitavastatin Compared with Atorvastatin andRosuvastatin on New-Onset Diabetes Mellitus in PatientsWith Acute Myocardial Infarction
This study investigates the impact of moderate-intensity pitavastatin compared to atorvastatin and rosuvastatin on the incidence of new-onset diabetes mellitus in patients with acute myocardial infarction, finding that pitavastatin is associated with a significantly lower incide…
DOI: 10.1016/j.amjcard.2018.06.017 -
Triglyceride-glucose index in predicting the risk of new-onset diabetes in the general population aged 45 years and older: a national prospective cohort study
This study investigates the association between the triglyceride-glucose index (TyG) and the risk of new-onset diabetes in Chinese adults aged 45 and older, finding a significant correlation and a nonlinear relationship that suggests TyG can be a predictive factor for diabetes r…
DOI: 10.1186/s12902-025-01848-w -
Prospective study of new-onset seizures presenting as status epilepticus in childhood
This study characterizes children with new-onset seizures presenting as status epilepticus at a tertiary care children's hospital, revealing key demographics, etiologies, and the utility of diagnostic imaging.
DOI: 10.1212/WNL.0b013e3181d0cca2 -
Diagnosis of epileptic syndrome after a new onset seizure and its correlation at long-term follow-up: Longitudinal study of 131 patients from the emergency room
This longitudinal study of 131 patients with new-onset seizures demonstrates the reliability of diagnosing epilepsy in the emergency room using CT scans and video-EEG, revealing that 94.1% of those diagnosed with epilepsy were confirmed as such during follow-up, while also highl…
DOI: 10.1016/j.eplepsyres.2011.06.013 -
Rabies encephalitis presenting with new-onset refractory status epilepticus (NORSE)
This case study details a 15-year-old girl who developed new-onset refractory status epilepticus due to rabies encephalitis, highlighting the challenges in diagnosis and the rapid progression of the disease.
DOI: 10.1212/CPJ.0000000000000372 -
New onset diabetes predicts clinical outcomes in patients with pancreatic adenocarcinoma
This multi-center retrospective cohort study investigates the prevalence and impact of new onset diabetes (NOD) on clinical outcomes in patients with pancreatic adenocarcinoma (PDAC), revealing that NOD is associated with worse overall survival and progression-free survival in b…
DOI: 10.21037/jgo-24-570 -
Meta-analysis: Inhibition of renin-angiotensin system prevents new-onset atrial fibrillation
This meta-analysis evaluates the effectiveness of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in preventing new-onset atrial fibrillation, finding an overall 18% risk reduction across trials, particularly in patients with heart failure.
DOI: 10.1016/j.ahj.2006.01.007 -
Risk of New-Onset Diabetes Mellitus Versus Reduction in Cardiovascular Events With Statin Therapy
This study investigates the risk of new-onset diabetes mellitus (NODM) and the reduction of major adverse cardiovascular events (MACE) in prediabetic patients undergoing statin therapy, finding that while statins increase the risk of NODM, they significantly reduce MACE, suggest…
DOI: 10.1016/j.amjcard.2013.10.043 -
Inflammatory activation in an unselected population of subjects with atrial fibrillation: links with structural heart disease, atrial remodeling and recent onset
This study investigates the levels of C-reactive protein (CRP) in patients with new onset atrial fibrillation, revealing that elevated CRP levels are associated with structural heart disease and atrial remodeling.
DOI: 10.1007/s11739-011-0557-z -
New-onset pain in the early phase and three months following stroke – data from a multicenter study
This study investigates the prevalence and distribution of new-onset pain in stroke patients initially and three months post-stroke, finding that anxiety symptoms are associated with increased pain occurrence.
DOI: 10.2147/jpr.s165482