Safety and Adverse Events Related to COVID-19 mRNA Vaccines; a Systematic Review

Introduction: Knowledge of vaccine-related adverse events is crucial as they are among the most important factors that cause hesitation in receiving vaccines. Therefore, we aimed to systematically review the adverse events related to the mRNA vaccines reported in the literature. Methods: A systematic literature search was carried out in the databases of Scopus, PubMed, Cochrane, and Web of Science. We selected original studies that explored the side effects of mRNA COVID-19 vaccines using a two-phase (title/abstract and full-text) screening process. Results: Cardiac complications were the most commonly reported severe adverse events. It appeared that systemic adverse reactions are more common after the second dose of vaccines. The number of adverse effects reported after the Pfizer vaccine was higher than other vaccines, mostly due to its earlier approval and more widespread use throughout the world. Cardiac adverse events had a higher prevalence but no significant association has been found between COVID-19 mRNA vaccines and cardiac adverse events except for myopericarditis. Conclusion: Vaccines play a crucial role in controlling the COVID-19 pandemic and decreasing mortalities and the results of the present review acknowledge the fact that the benefits outweigh the adverse events of these vaccines.