Decreasing Incidence of the Multisystem Inflammatory Syndrome in Children Over 3 Pandemic Waves

Abstract

In this nationwide retrospective study, a substantial decline in the incidence of multisystem inflammatory syndrome in children over 3 successive pandemic waves characterized by different severe acute respiratory syndrome coronavirus 2 variants was documented—from 3.4 of 1000 to 1.1 of 1000 and finally to 0.25 of 1000 confirmed severe acute respiratory syndrome coronavirus 2 positive cases (P < 0.0001), respectively, whereas clinical findings and severity did not significantly vary.

Incidence and Clinical Phenotype of Multisystem Inflammatory Syndrome in Children After Two SARS-CoV-2 Pandemic Waves: A Croatian Prospective Nationwide Study

“…Three previous studies suggested a comparable probability of MIS-C related to SARS-CoV2 Alpha and Delta strain infections., 2,3,6 while a German, a British and a Greek study pointed out a higher risk of MIS-C with Alpha than with the Delta strain. 5,9,10 Premorbid characteristics, disease presentation and flow, organ system involvement, the incidence of severe disease form, regular treatability and almost complete full recovery (except for one 10-year-old boy with severe hemodynamic instability at hospital admission) without residues observed in the present cohort of MIS-C patients are in line with the general knowledge on the topic and observations from different other countries. [1][2][3][4][5][6][7] In line with the Danish and Israeli nationwide studies, we observed no indication that would relate viral strain to symptom/disease severity or the outcomes.…”

“…Three previous studies suggested a comparable probability of MIS-C related to SARS-CoV2 Alpha and Delta strain infections., 2,3,6 while a German, a British and a Greek study pointed out a higher risk of MIS-C with Alpha than with the Delta strain. 5,9,10…”

Immunology of Multisystem Inflammatory Syndrome after COVID-19 in Children: A Review of the Current Evidence

“…In the USA, MIS-C incidence and complications were significantly reduced during the Delta period compared to previous pandemic waves [ 17 ]. The same trend was also confirmed in Greece, with the estimated incidence of MIS-C being notably reduced from 3.5/1000 in Alpha to 0.25/1000 in the Delta predominance period [ 18 ]. After the onset of Omicron, the incidence and severity of MIS-C was even lower compared to Alpha and Delta variant waves in Israel [ 19 ], while in a study in South Africa in November 2021, no patients who fulfilled WHO criteria for MIS-C diagnosis were encountered [ 9 ].…”

Brucellosis With Pericardial Effusion and Splenic Abscess: An Unusual Presentation

“…1,2 Likewise, splenic abscesses are extremely rare, with only 4 available reports worldwide since 1995. 3–6 Although these manifestations are uncommon, they do not seem to confer higher mortality risk. Due to epidemiologic context and mimicking signs and symptoms, our patient was initially diagnosed with MIS-C.…”