JMIR Publications

ABSTRACT

COVID-19, a highly contagious respiratory disease, has rapidly emerged as a global pandemic, impacting billions of people worldwide. Vaccination against COVID-19 is considered one of the most effective strategies to control its spread. However, due to variations in populations and the ongoing development of vaccines, it is expected that a certain number of individuals may experience adverse events following the COVID-19 vaccination. In this comprehensive study, we analyzed data from the Centers for Disease Control and Prevention (CDC) and the Vaccine Adverse Event Reporting System (VAERS) to assess the safety of COVID-19 vaccines administered between 2020 and 2022. To gain a broader understanding of reported post-vaccination symptoms, we categorized them into System Organ Classes (SOCs) according to the Medical Dictionary for Regulatory Activities (MedDRA). Additionally, we conducted temporal analysis to examine the trends in all adverse event reports and serious adverse event (SAE) reports only. We also compared the similarity of symptoms across various regions within the United States. This approach enabled us to identify commonalities and connections between symptoms reported in different geographical areas. Our findings revealed that the most frequently reported symptoms following COVID-19 vaccination were headache (N = 141,186), pyrexia (N = 122,120), and fatigue (N = 121,910). The most common symptom combination was chills and pyrexia (N = 56,954). Over time, we observed a decreasing reporting rate for COVID-19-related adverse events. General disorders and administration site conditions (SOC 22) were the most prevalent symptoms reported. Notably, death was the most frequently reported symptom in serious adverse event reports. During the initial vaccination stage, Moderna exhibited a higher reporting rate of adverse events compared to Pfizer. However, as more data was collected, it became apparent that the overall rates of adverse events between the two vaccines were comparable. In terms of spatial analysis, the middle and north regions displayed a higher reporting rate of COVID-19 adverse events, while the northeast and northwest regions showed notable similarity in reported COVID-19 symptoms. In conclusion, our study provides significant clinical insights into vaccine safety monitoring and development. The combination of temporal analysis and symptom similarity visualization provided a comprehensive understanding of COVID-19 adverse event landscape. These findings can inform healthcare professionals, researchers, and regulatory authorities about emerging safety issues and help guide decision-making processes related to patient safety and public health.