Multisystem Inflammatory Syndrome After Breakthrough SARS-CoV-2 Infection in 2 Immunized Adolescents, United States

Lyndsey D. Cole; Molly Slate; Samantha Minneman; Michael J. Bozzella


Emerging Infectious Diseases. 2022;28(7):1456-1459. 

In This Article

Abstract and Introduction


Eight weeks after having laboratory-confirmed SARS-CoV-2 breakthrough infections, 2 otherwise healthy, fully immunized adolescent patients in the United States who were experiencing related signs and symptoms were diagnosed with multisystem inflammatory syndrome in children. Our findings indicate that COVID-19 vaccination does not completely protect adolescents against multisystem inflammatory syndrome.


Multisystem inflammatory syndrome in children (MIS-C) is a hyperinflammatory illness occurring after SARS-CoV-2 infection; ≈30% of case-patients are adolescents.[1] The United States reported 7,880 MIS-C cases and 66 deaths as of March 28, 2022.[1] MIS-C is an exception to the lower incidence and death from SARS-CoV-2–associated health conditions in children than adults.[2] In April–June 2020, estimated MIS-C incidence across 7 US jurisdictions was 316 (95% CI 278–357) cases per 1 million SARS-CoV-2 infections in persons <21 years of age.[3] The small but serious risk of MIS-C has been cited in support of pediatric SARS-CoV-2 immunization.[4,5]

The BNT162b2 Pfizer-BioNTech mRNA COVID-19 vaccine ( was approved in December 2020 for children ≥16 years of age and in May 2021 for children 12–15 years of age.[6] As of April 20, 2022, a total of 68% of US children 12–17 years of age had been fully immunized.[6] Data about the effects of SARS-CoV-2 immunization on MIS-C are limited, although some evidence suggests the vaccine offers protection against MIS-C in adolescents.[7,8] We describe 2 cases of MIS-C after breakthrough SARS-CoV-2 infection in fully immunized adolescents.