SARS-CoV-2 Vaccination Status and MIS-C Incidence: A Systematic Review

Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious condition associated with pediatric SARS-CoV-2 infection. While COVID-19 vaccines prevent infection and reduce severity, less conclusive evidence exists regarding their role in preventing MIS-C during breakthrough infections. This systematic review assessed the impact of SARS-CoV-2 vaccination on MIS-C risk during breakthrough infection. Cross-sectional studies, surveillance studies, and cohort studies were included. Of the 944 studies identified, 6 were included. A significant protective effect was seen in patients who received two doses of SARS-CoV-2 vaccination after exclusion of a biased sample (d= 0.71 [95% CI 0.07 to 1.35; p=0.03]). A trend towards a protective effect was seen after one dose of vaccination, but this effect was not statistically significant. Current literature supports a protective effect of two doses of SARS-CoV-2 vaccination against development of MIS-C in breakthrough COVID-19. The evidence supports clinician advocacy for continued vaccination of children against SARS-CoV-2.