Multisystem Inflammatory Syndrome Following SARS-CoV-2 Vaccination in Two Children

Area of Science:

• Pediatric immunology
• Vaccine adverse events
• Infectious disease

Background:

• Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious condition following SARS-CoV-2 infection.
• Vaccination against SARS-CoV-2 is crucial for pediatric protection, but surveillance for rare adverse events is necessary.

Observation:

• Two pediatric cases of multisystem inflammatory syndrome post-vaccination (MIS-V) occurred within six weeks of the first Pfizer-BioNTech SARS-CoV-2 vaccine dose.
• One child presented with peri-myocarditis and shock, while the other exhibited Kawasaki disease features.
• Both patients tested positive only for SARS-CoV-2 antispike (anti-S) antibodies, indicating a post-vaccine event.

Findings:

• Both MIS-V cases responded well to standard treatments like intravenous immunoglobulins and corticosteroids.
• Measuring both anti-S and anti-nucleocapsid (anti-NC) antibodies is crucial for differentiating MIS-V from MIS-C post-infection.

Implications:

• This report underscores the importance of continued surveillance for rare adverse events following immunization in children.
• Accurate antibody testing can distinguish between post-vaccine and post-infection inflammatory syndromes, aiding clinical management.
• Understanding MIS-V is vital, especially with expanding SARS-CoV-2 vaccination eligibility in younger age groups.