Incidence of Pediatric Acute Disseminated Encephalomyelitis During the Coronavirus Disease 2019 Pandemic in South Korea.

Background: Acute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating disorder of the central nervous system that is usually triggered by infections. We aimed to determine the temporal trends in the incidence of ADEM before and during the pandemic and their correlation with viral epidemiology.

Methods: We conducted a nationwide, population-based, retrospective, ADEM cohort study by using the Health Insurance Review and Assessment Service database. New-onset ADEM was defined as a patient (age <19 years) who was hospitalized with a diagnostic code of G04.0, G36.8, and G36.9 and a prescription of intravenous methylprednisolone. The National Infectious Disease Surveillance System was used to collect the nationwide viral epidemics.

Results: A total of 185 new-onset pediatric ADEM cases were included. The mean patient age was 7.0 ± 4.9 years. The incidence of ADEM was 0.34 to 0.48 of 100,000 persons per year before the pandemic, which dropped to 0.22 of 100,000 persons per year during the first pandemic year. The risk of ADEM occurrence was approximately 1.74% higher during the prepandemic years compared with the first pandemic year (odds ratio = 1.017, P = 0.009). There was a weak positive correlation between acute respiratory viral infection and ADEM incidence (r = 0.28, P = 0.03).

Conclusion: This study demonstrates how infection control during the early coronavirus disease 2019 (COVID-19) pandemic influenced the incidence of ADEM. The low incidence of ADEM in the early COVID-19 pandemic may be related to the decline in acute respiratory viral infections, which are potential triggers of ADEM.