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

Area of Science:

• Immunology
• Pediatrics
• Infectious Diseases

Background:

• Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious complication of COVID-19.
• Understanding the immune response to COVID-19 vaccination in children with a history of MIS-C is crucial for guiding vaccination strategies.

Purpose of the Study:

• To assess the serological response to primary series COVID-19 vaccination in children with a history of MIS-C.
• To compare antibody responses, including neutralizing and functional titers, between children with a history of MIS-C, COVID-19, and healthy controls.

Main Methods:

• Prospective enrollment of seven children hospitalized with MIS-C.
• Longitudinal measurement of SARS-CoV-2 spike protein IgG antibodies pre- and post-Pfizer-BioNTech vaccination.
• Comparison of binding, pseudovirus neutralizing, and antibody-dependent cell-mediated cytotoxicity (ADCC) titers against reference and Omicron variants.

Main Results:

• SARS-CoV-2 variant cross-reactive IgG antibodies waned after MIS-C but were boosted and maintained for up to 3 months post-vaccination.
• Vaccination elicited broad binding antibodies in all groups (MIS-C, COVID-19, healthy controls).
• Pseudovirus neutralizing and ADCC titers were significantly reduced against the Omicron variant in all groups, including those with a history of MIS-C.

Conclusions:

• COVID-19 vaccination effectively boosts antibody levels in children with a history of MIS-C.
• Reduced neutralizing and functional antibody responses against Omicron variants highlight potential limitations of current vaccines in this population.
• Further research is needed to optimize vaccination strategies for children with a history of MIS-C to ensure robust protection against emerging variants.