Anecdotal Report: Resolution of Purported mRNA Vaccine-Induced Arrhythmia Following Novavax Administration

This case report and clinical overview examines rare but persistent post-vaccination cardiac complications associated with mRNA COVID-19 vaccine platforms, which exhibit a higher incidence rate ratio of post-vaccination arrhythmia compared to traditional or vector-based designs. Currently, there is a distinct clinical gap regarding the management of long-term, vaccine-associated arrhythmias that remain refractory over multiple years. We present the case of a 77-year-old male with no prior cardiac history who developed persistent ventricular bigeminy and frequent premature ventricular contractions (PVCs) following a primary mRNA vaccination series (Moderna). The arrhythmia continuously recurred through subsequent mRNA booster doses (Moderna and Pfizer) over a three-year period. Extensive clinical evaluations, including echocardiography and myocardial perfusion stress testing, ruled out structural heart disease, ischemia, or metabolic abnormalities. Because the overall arrhythmia burden was measured at a low 6%, below the standard 15% clinical treatment threshold, no antiarrhythmic medications or invasive interventions were initiated. However, following a self-initiated platform switch to a single dose of the protein-based recombinant adjuvanted vaccine (Novavax), the patient’s multi-year arrhythmia resolved completely within days, and normal sinus rhythm has been continuously documented for over a year. Putative mechanisms for mRNA-induced myocardial electrical instability include prolonged intracellular processing of encoded spike proteins within host cardiomyocytes, lipid nanoparticle-mediated systemic inflammation, and autoimmune molecular mimicry—cascades that are entirely avoided by recombinant protein vaccines. Ultimately, this case highlights a profound temporal association between long-term ventricular arrhythmia and mRNA vaccines, followed by rapid, sustained resolution upon switching platforms. Clinicians should consider enhanced, long-term arrhythmia monitoring for select patients presenting with post-mRNA palpitations, and therapeutic platform-switching to non-mRNA configurations warrants immediate further investigation as a safe, highly viable mitigation strategy for persistent vaccine-associated cardiac symptoms.