Risk of Encephalitis and Meningitis after COVID-19 Vaccination in South Korea

1. In this large population-based study of adults in South Korea, there was an increased risk of developing encephalitis within 28 days of COVID-19 vaccination only for those who received the AstraZeneca (ChAdOx1-S) vaccine, but no increased risk of developing meningitis post-vaccination. 

Evidence Rating Level: 2 (Good)

Over 5.5 billion people worldwide have received at least one dose of a COVID-19 vaccine. Encephalitis and meningitis have been reported as rare but serious adverse events of special interest (AESIs). In this self-controlled case series analysis, researchers used data from the Korea Disease Control Agency between February 2021 and March 2022 to assess the medical claims for adults in Korea who had received at least one dose of a COVID-19 vaccine. The risk window for developing meningitis or encephalitis was defined as days 1-28 after vaccination, while the control window was defined as the remainder of the 240-day follow-up period. Overall, there were 129,956,027 COVID-19 vaccine doses administered to a total of 44,564,345 participants. Among this group, there were 251 cases of encephalitis and 398 cases of meningitis diagnosed during the risk window. There was an increased risk of developing encephalitis in the first 28 days after COVID-19 immunization, which was only significant for those who received the AstraZeneca (ChAdOx1-S) vaccine (IRR 1.26; 95% CI 1.08–1.47). There was no increased risk of developing meningitis observed following the administration of any type of COVID-19 vaccine (IRR 1.03; 95% CI 0.91–1.16). Future research could examine whether there are any long-term risks for neurological complications after COVID-19 vaccination, which was not addressed in this study. Overall, this study demonstrates an increased risk of developing encephalitis, only for those who received the AstraZeneca vaccine, and no significant association between COVID-19 vaccination and meningitis. 

Click to read the study in BMC Medicine

Image: PD

©2024 2 Minute Medicine, Inc. All rights reserved. No works may be reproduced without expressed written consent from 2 Minute Medicine, Inc. Inquire about licensing here. No article should be construed as medical advice and is not intended as such by the authors or by 2 Minute Medicine, Inc.