INTRODUCTION: This study compares the period during which thromboembolic disease develops after contact with the virus before, during, and after the pandemic. METHODS: In this study, the medical records of patients with a preliminary diagnosis of myocardial infarction (MI), pulmonary embolism (PE), and ischemic stroke who presented to the Emergency Department before, during, and after the pandemic (when vaccination rates increased) were retrospectively examined. Data on whether these patients had COVID-19 or were vaccinated, the time interval between infection/vaccination and the onset of these conditions, and the prognosis were analyzed. RESULTS: In the MI group, patients developed embolism the longest after infection and the shortest after vaccination. Among MI patients, the rate of those who received the BioNTech vaccine during the normalization period was higher than that of those who received Sinovac (p = 0.005). In stroke patients, during the pandemic, the time to post-vaccine embolism was shorter (p <
0.001). Additionally, infection and vaccination increased the mortality rate in stroke and PE patients (p <
0.001). CONCLUSION: This study demonstrates that thromboembolic events can occur at varying rates and durations after exposure to the virus. While the causes of thrombosis are multifactorial, contact with the virus may act as a triggering factor, even if COVID-19 does not have a direct effect.