Abstract Body (Do not enter title and authors here): Background: Rarely, SARS-CoV-2 will lead to myocarditis associated with Multisystem Inflammatory Syndrome in Children (MIS-C). It remains unclear why MIS-C only targets specific children. Coxsackieviruses (CV) are prevalent infections during childhood and, like SARS-CoV-2, can lead to viral myocarditis. To explore an association with MIS-C we investigated the sero-epidemiology of CV in admitted pediatric patients.
Method: A retrospective case control study was performed by chart review of children (age ≤ 21) admitted to a tertiary care hospital with CV serological testing from January 2017 to August 2023. Clinical, laboratory and imaging findings were used to classify patients as MIS-C and CV-unlikely or CV-possible for non-MIS-C patients.
Results: Out of 182 admissions (179 patients, median age 6), CVB complement fixation (CF) assay on serotypes B1-B6 and CVA immunofluorescence assay IgG on serotypes A7, A9, A16, and A24 were positive in at least one serotype in 59.2% and 80.7% of cases respectively. We observed a significant drop in CVB CF seropositivity during the peak of social distancing in 2020. The CVB titers in CV-possible cases and MIS-C were similar. The likelihood of elevated CVB CF titers was significantly higher in MIS-C than CV-unlikely group (OR: 1.92, 95% CI: 1.02-3.63, p: 0.04). CVB CF titer trended toward higher values in African Americans compared to Whites (OR: 1.57, 95% CI: 0.98-2.50, p-value:0.057). As previously shown, the frequency of MIS-C was considerably higher in African Americans than Whites (18.1%, versus 9%, p: 0.1).
Conclusion: Higher likelihood of elevated CVB CF titers in patients with MIS-C and in African Americans along with a notable higher frequency of MIS-C in African Americans warrant further investigation into the role of CVB infection in MIS-C development.