What is Known: • The number of immunosuppressed patients with coronavirus disease 2019 is increasing. • Viral infections have the potential for greater severity in immunocompromised children. What is New: • Seroprevalence for severe acute respiratory syndrome coronavirus 2 in immunocompromised pediatric patients was 31%. • A quarter of the serology-positive patients reported mild symptoms and none of them developed multisystem inflammatory syndrome in children associated with coronavirus disease 2019.