Abstract Details

Title Reporting Rates of Encephalopathy Post-COVID-19 Vaccination: A Vaccine Adverse Event Reporting System (VAERS)

Topic Autoimmune Neurology

Presentation(s) S3 - Autoimmune Neurology 1: Mechanisms of Disease, Clinical Practice (1:24 PM-1:36 PM)

Poster/Presentation
Number 003

Background Encephalopathy has been reported in COVID-19 vaccinations.

Objective To investigate whether there is an association between Encephalopathy and COVID-19 vaccination.

Design/Methods The reporting rate of Encephalopathy cases after COVID-19 vaccination was compared to the reporting rate of Encephalopathy after all other vaccinations in 3 periods: COVID-19 vaccination (December 2020 - July 2021); COVID-19 pandemic outside the vaccination period (April 2020 - November 2020) and time outside both the COVID-19 vaccination and the pandemic (January 2019 - August 2019). Self-controlled case series analysis and case-centered analysis was used. Six weeks after vaccination was defined as the risk period of probable association between Encephalopathy and COVID-19 vaccination.

Results 371 and 4 cases of Encephalopathy were reported after COVID-19 vaccination and all other vaccinations respectively during the COVID-19 vaccination period. The reporting rate of Encephalopathy after COVID-19 vaccination was significantly higher than the reporting rate of Encephalopathy after all other vaccinations (1.9 vs 0.017 per million p<0.00001). However, the reporting rate of Encephalopathy after COVID-19 vaccination was within the incidence range expected in the general population. 12 and 23 cases of Encephalopathy were reported after vaccination during the pandemic period and outside the pandemic period. Using self-controlled and case centered analyses, there was a significant difference in the reporting rate of Encephalopathy after COVID-19 vaccination between the risk and control periods (94.33% vs 1.08-2.70% p< 0.0001). The reporting rate of Encephalopathy after Pfizer was significantly higher compared to that of Encephalopathy after Moderna and Johnson & Johnson vaccinations. However, all reporting rates were within the incidence range reported in the general population.

Conclusions

There is no association between Encephalopathy 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.

Authors/Disclosures
Kazim Jaffry PRESENTER	Mr. Jaffry has nothing to disclose.
Kranthi K. Mandava	Mr. Mandava has nothing to disclose.
Mustafa Jaffry	Mr. Jaffry has nothing to disclose.
	No disclosure on file
	No disclosure on file
Nizar Souayah, MD, FAAN (NJMS)	Dr. Souayah has received publishing royalties from a publication relating to health care.