Cardiac Adverse Events after Vaccination—A Systematic Review

Influenza associated cardiac arrhythmia- a systematic review

BACKGROUND

Influenza infection is rarely associated with cardiac conduction disorder. Cardiac arrhythmias due to such an infection have a full spectrum with ventricular arrythmias being the most common.

METHODS

In our systematic review from PubMed, OVID Medline and EMBASE we have identified 23 articles describing arrythmias associated with different influenza infection. Most of them were case reports where ventricular arrhythmias were the most common.

RESULTS

Complete heart block after influenza infection is usually temporary and a permanent pacemaker is rarely needed. There are reports of Influenza associated with arrhythmias in adults, neonates, and even fetuses in pregnant woman. Different mechanisms were described in literatures by which influenza causes arrhythmias such as interleukin 6 & tumor necrosis factor-alpha mediated inflammatory response, sympathetic overactivation, focal myocarditis and cleavage of angiotensin converting enzyme 2 protein which is cardioprotective.

CONCLUSIONS

ACE 2 binder influenza viruses have more prone to be associated with cardiac conduction disorder. Oseltamivir for influenza infection is also associated with bradycardia and can shorten or lengthen QT segment. Influenza vaccination has found to be protective from cardiac arrhythmia.

Sex Differences in Serious Adverse Events Reported Following Booster Doses of COVID-19 Vaccination in Thailand: A Countrywide Nested Unmatched Case-Control Study

A booster dose of a COVID-19 vaccine has been proven effective in restoring vaccine effectiveness and is currently recommended for use in some populations at risk of severe COVID-19 infection. Since sex differences in adverse events are significant in response to the vaccines, the safety of booster selection must be studied to avoid serious adverse events (SAE), such as life-threatening diseases. First, this study aimed to identify sex differences in SAE incidences using a prospective cohort design. Second, a nested unmatched case-control study was used to identify factors associated with reported SAE within 30 days after the booster shot. Multivariable logistic regression indicated the adjusted odds ratio by accounting for host and vaccine variables, thus, policy effects. The findings confirmed that SAE was rare and that age-sex-dominated disease classifications differed. Specific to SAE following the booster dose, we found that females aged 12-40 had a higher risk of being reported with SAE than males of the same age, while males over 50 had a higher risk than females. Other risk factors identified were the presence of metabolic syndrome and the use of certain vaccine brands. Mechanisms could be explained by individual host responses rather than the vaccines' direct effect. Therefore, SAE could be preventable by age-sex-specific vaccine selection, post-vaccination precautions, and early symptom detection. Future vaccine development should aim to limit host-specific reactogenicity for safety concerns.

SARS-CoV-2 vaccines and myocarditis

The development of safe and effective vaccines against severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) was a major turning point in the fight against the Coronavirus 2019 (COVID-19) pandemic. However, pharmacovigilance has revealed a small but significant incidence of cardiac inflammation manifesting clinically as myocarditis or pericarditis, particularly in younger vaccine recipients. The incidence is the highest among men under age 40 within a week of receiving the second dose of the mRNA vaccine. In this review, we summarise the evidence for, and guidelines in relation to, SARS-CoV2 vaccine-related myocarditis.

Vaccination-Associated Myocarditis and Myocardial Injury

SARS-CoV-2 vaccine-associated myocarditis/myocardial injury should be evaluated in the contexts of COVID-19 infection, other types of viral myocarditis, and other vaccine-associated cardiac disorders. COVID-19 vaccine-associated myocardial injury can be caused by an inflammatory immune cell infiltrate, but other etiologies such as microvascular thrombosis are also possible. The clinical diagnosis is typically based on symptoms and cardiac magnetic resonance imaging. Endomyocardial biopsy is confirmatory for myocarditis, but may not show an inflammatory infiltrate because of rapid resolution or a non-inflammatory etiology. Myocarditis associated with SARS-COVID-19 vaccines occurs primarily with mRNA platform vaccines, which are also the most effective. In persons aged >16 or >12 years the myocarditis estimated crude incidences after the first 2 doses of BNT162b2 and mRNA-1273 are approximately 1.9 and 3.5 per 100 000 individuals, respectively. These rates equate to excess incidences above control populations of approximately 1.2 (BNT162b2) and 1.9 (mRNA-1273) per 100 000 persons, which are lower than the myocarditis rate for smallpox but higher than that for influenza vaccines. In the studies that have included mRNA vaccine and SARS-COVID-19 myocarditis measured by the same methodology, the incidence rate was increased by 3.5-fold over control in COVID-19 compared with 1.5-fold for BNT162b2 and 6.2-fold for mRNA-1273. However, mortality and major morbidity are less and recovery is faster with mRNA vaccine-associated myocarditis compared to COVID-19 infection. The reasons for this include vaccine-associated myocarditis having a higher incidence in young adults and adolescents, typically no involvement of other organs in vaccine-associated myocarditis, and based on comparisons to non-COVID viral myocarditis an inherently more benign clinical course.

Current evidence of COVID-19 vaccination-related cardiovascular events

Currently, the world is recovering from the shock of the coronavirus disease 2019 (COVID-19) pandemic; however, this situation is still fragile. Health authorities recommend administering COVID-19 vaccines as the safest and most reliable tool for eliminating COVID-19. Subsequent to the extensive administration of the COVID-19 vaccines, a series of cardiovascular adverse effects have been reported. This comprehensive review aimed to provide an update on the etiology, pathophysiology, clinical features, and management of the cardiovascular adverse events associated with COVID-19 vaccines, including myocarditis, pericarditis, thrombosis with thrombocytopenia syndrome, myocardial infarction, cardiac arrhythmias, hypertension, and stress-induced cardiomyopathy. The benefits of COVID-19 vaccination far outweigh the reported adverse events. It would be clinically important to provide diagnostic scoring systems to differentiate COVID-19-related cardiovascular adverse events from other causes and develop therapeutic approaches for their management. Further evaluation of cardiovascular adverse events of the COVID-19 vaccines is crucial for implementing vaccination programs and developing safer and more reliable vaccines.

Comparison of COVID-19 Vaccine-Associated Myocarditis and Viral Myocarditis Pathology

The COVID-19 pandemic has led to significant loss of life and severe disability, justifying the expedited testing and approval of messenger RNA (mRNA) vaccines. While found to be safe and effective, there have been increasing reports of myocarditis after COVID-19 mRNA vaccine administration. The acute events have been severe enough to require admission to the intensive care unit in some, but most patients fully recover with only rare deaths reported. The pathways involved in the development of vaccine-associated myocarditis are highly dependent on the specific vaccine. COVID-19 vaccine-associated myocarditis is believed to be primarily caused by uncontrolled cytokine-mediated inflammation with possible genetic components in the interleukin-6 signaling pathway. There is also a potential autoimmune component via molecular mimicry. Many of these pathways are similar to those seen in viral myocarditis, indicating a common pathophysiology. There is concern for residual cardiac fibrosis and increased risk for the development of cardiomyopathies later in life. This is of particular interest for patients with congenital heart defects who are already at increased risk for fibrotic cardiomyopathies. Though the risk for vaccine-associated myocarditis is important to consider, the risk of viral myocarditis and other injury is far greater with COVID-19 infection. Considering these relative risks, it is still recommended that the general public receive vaccination against COVID-19, and it is particularly important for congenital heart defect patients to receive vaccination for COVID-19.

Risks of Cardiac Arrhythmia Associated with COVID-19 Vaccination: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to summarize the current evidence regarding the association between coronavirus disease 2019 (COVID-19) vaccination and the risk of cardiac arrhythmia. MEDLINE, via PubMed and OVID, Scopus, CENTRAL, and Web of Science were searched using the relevant keywords to identify the relevant citations. Comprehensive Meta-analysis and Review Manager 5.4.1 were used for all the statistical analyses. Seventeen studies (n = 567,033,087 patients) were included. The pooled analysis showed that the incidence of cardiac arrhythmia post-COVID-19 vaccination with Pfizer, Moderna, AstraZeneca, CoronaVac, and Sinopharm was 0.22%, 95% CI: (0.07% to 0.66%), 0.76%, 95% CI: (0.04% to 12.08%), 0.04%, 95% CI: (0.00% to 0.98%), 0.01%, 95% CI: (0.00% to 0.03%), and 0.03%, 95% CI: (0.00% to 18.48%), respectively. Compared to CoronaVac, Pfizer, Moderna, AstraZeneca, and Sinopharm had a higher incidence ratio rate (IRR; 22-times, 76-times, 4-times, and 3-times higher), respectively. Likewise, Pfizer, Moderna, and AstraZeneca showed a higher IRR than Sinopharm (7.3-times, 25.3-times, and 1.3-times higher). The current evidence shows that the incidence rate (IR) of cardiac arrhythmia post-COVID-19 vaccination is rare and ranges between 1 and 76 per 10,000. mRNA vaccines were associated with a higher IR of arrhythmia compared to vector-based vaccines. Inactivated vaccines showed the lowest IR of arrhythmia.