Short-, mid-, and long-term complications after multisystem inflammatory syndrome in children over a 24-month follow-up period in a hospital in Lima-Peru, 2020-2022.

Objective: To determine the short-, mid-, and long-term complications after multisystem inflammatory syndrome in children (MIS-C) over a 24-month follow-up period in a hospital in Lima, Peru, 2020-2022, and to explore differences according to the immunomodulatory treatment received and type of SARS-CoV-2 virus circulating. Methods: Ambispective 24-month follow-up study in children <14 years of age diagnosed with MIS-C at the Hospital Nacional Edgardo Rebagliati Martins (HNERM). Results: A total of 62 children were admitted with MIS-C. The most common short-term complications and serious events were intensive care unit (ICU) admission, invasive mechanical ventilation (IMV) due to respiratory failure, and shock; predominantly during the second pandemic wave (lambda predominance) and in children that received intravenous immunoglobulin (IVIG) plus a corticosteroid. Two patients died during the first wave due to MIS-C. During prospective follow-up (median of 24 months; IQR: 16.7-24), only 46.7% of patients were followed for >18-24 months. Of the total, seven (11.3%) patients were identified with some sequelae on discharge. Among the 43 remaining children, sequelae persisted in five (11.6%) cases (neurological, hematological, and skin problems). Six patients (13.9%) presented with new onset disease (hematologic, respiratory, neurological, and psychiatric disorders). One patient died due to acute leukemia during the follow-up period. None of them were admitted to the ICU or presented with MIS-C reactivation. Two patients presented persistence of coronary aneurysm until 8- and 24-month post-discharge. Conclusion: In our hospital, children with MIS-C frequently developed short-term complications and serious events during the acute phase, with less frequent complications in the mid- and long-term. More studies are required to confirm these findings.