Association Between COVID-19 Vaccination and Cerebrovascular Accidentsin Adults: A Vaccine Adverse Event Reporting System (VAERS) Study

ABSTRACT

Objective: To investigate whether there is an association between cerebrovascular accidents (CVA's) and COVID-19 vaccination Background: CVA's have been reported in severe COVID-19 infections and are attributed to infection-related hypercoagulability and inflammation. Design/Methods: The reporting rate of CVA cases after COVID-19 vaccination was compared to the reporting rate of CVA after all other vaccinations in three periods pre-COVID period (January 2019-August 2019), pre-COVID-19 vaccine period (April 2020-November 2020), and vaccine period (December 2020-July 2021). Results: 812 and 17 cases of CVA were reported after COVID-19 vaccination and all other vaccinations, respectively, during the COVID-19 vaccination period. The reporting rate of CVA after COVID-19 vaccination was significantly higher than the rate after all other vaccines (4.2 vs 0.07 per million p<0.00001). However, it was within the incidence range expected in the general population. Only 2 cases of CVA were reported after vaccination during the pandemic period and no cases outside the pandemic period. Based upon self-controlled and case-centered analyses, there is a significant difference in the reporting rate of CVA after COVID vaccination between the risk period (six weeks after vaccination was defined as the risk period of probable association) and control period (93.97% vs 1.97-2.96% p< 0.0001). The reporting rate of CVA after Pfizer was significantly higher compared to CVA after Moderna and Johnson and Johnson vaccinations (5.9 vs 2.8 vs 3.2 per million p<0.0001). However, all reporting rates were within the expected incidence range reported in the general population. Conclusions: There is no association between CVA and COVID-19 vaccination. Furthermore, this work is based on passive surveillance where several limitations exist, which include under-reporting, differential reporting and nonreported or undiagnosed concomitant COVID-19 infection. These factors preclude establishing a cause-effect relationship. Controlled studies are needed for further investigation.