Serologic responses to COVID-19 vaccination in children with history of multisystem inflammatory syndrome (MIS-C)

Understanding the serological responses to COVID-19 vaccination in children with history of MIS-C could inform vaccination recommendations. We prospectively enrolled seven children hospitalized with MIS-C and measured SARS-CoV-2 binding IgG antibodies to spike protein variants longitudinally pre-and post-Pfizer-BioNTech BNT162b2 primary series COVID-19 vaccination. We found that SARS-CoV-2 variant cross-reactive IgG antibodies variably waned following acute MIS-C, but were significantly boosted with vaccination and maintained for up to 3 months. We then compared post-vaccination binding, pseu-dovirus neutralizing, and functional antibody-dependent cell-mediated cytotoxicity (ADCC) titers to the reference strain (Wuhan-hu-1) and Omicron variant (B.1.1.529) among previously healthy children (n = 16) and children with history of MIS-C (n = 7) or COVID-19 (n = 8). Despite the breadth of binding antibodies elicited by vaccination in all three groups, pseudovirus neutralizing and ADCC titers were sig-nificantly reduced to the Omicron variant.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Understanding the serological responses to COVID-19 vaccination in children with history of MIS-C could provide valuable insights for vaccination recommendations. A study was conducted on seven hospitalized children with MIS-C to measure the levels of SARS-CoV-2 binding IgG antibodies before and after Pfizer-BioNTech BNT162b2 vaccination. The findings showed that cross-reactive IgG antibodies to SARS-CoV-2 variants declined after acute MIS-C, but were significantly boosted and maintained for up to 3 months following vaccination.