Background/Objectives: Multisystem Inflammatory Syndrome in children (MIS-C) is a rare but severe post-infectious complication of COVID-19, that often requires admission to the Pediatric Intensive Care Unit (PICU). The present study aimed to compare the demographic, clinical and laboratory characteristics between children diagnosed with MIS-C who were admitted to the PICU or did not require PICU admission. Methods: Children diagnosed with MIS-C from September 2020 to April 2023 were included in this case-control study. Patient’s demographic, clinical and laboratory data, were collected from medical records. Results: Fifty children with MIS-C were included in the study [median (IQR) age: 7.5 (4.3, 11.4) years, 28/50 (56%) males]. Twenty-two (22/50, 44%) children required admission to the PICU. In the multivariate regression analysis, hepatic (OR:12.89, 95%CI: 1.35-123.41, p-value=0.03) and cardiological involvement (OR:34.55, 95%CI: 2.2-541.91, p-value=0.01) were significantly associated with hospitalization at the PICU. Regarding the laboratory and imaging parameters during the first 48 hours from admission, D-dimer levels higher than 4μg/mL and decreased Left Ventricular Ejection Fraction were associated with an increased risk of PICU admission (OR:7.95, 95%CI:1.48-42.78, p-value=0.02 and OR=1.28, 95%CI:1.07-1.53, p-value=0.01). Children who were admitted to the PICU were more likely to develop complications during their hospitalization (10/22, 45.5% vs. 3/28, 10.7%, p-value=0.005) and were hospitalized for more days, than children in the pediatric wards (median length of stay (IQR): 20 (15,28) days vs. 8.5 (6, 14) days, p-value<0.001). Conclusions: In the present study, cardiovascular, hepatic involvement and increased D-dimer levels in children with MIS-C were associated with admission to the PICU.

This is a SARS-CoV-2 seroepidemiological study in pediatric population(0-16 years) during BA.5 Omicron predominance period in Athens metropolitan area. Serum samples were tested for SARS-CoV-2 nucleocapsid antibodies(Abs-N), representing natural infection during three sub-periods of BA.5 predominance: 01/05/2022-31/08/2022(period A), 01/09/2022-31/12/2022(period B) and July 2023(period C) and epidemiological data were collected. Additionally in period C Abs-N seronegative samples were tested for SARS-CoV-2 spike antibodies(Abs-S). A total of 878 children were tested (males:51.3%) with median age(IQR): 108(36-156) months and seropositivity during the 3 subperiods was: A:292/417(70%), B:288/356(80.9%), C:89/105(84.8%), P-value<0.001. SARS-CoV-2 seropositivity increased for from period A to C for 0-1-year (P-value: 0.044), 1-4 years (P-value: 0.028) and 6-12 years children (P-value: 0.003). Children 6-12y had the highest seroposi-tivity rates in all subperiods (A: 77.3%, B: 91.4% and C: 95.8%). A significant correlation of monthly SARS-CoV-2 median antibody titers with monthly seropositivity rates was detected (rs:0.812, P-value:0.008). During period C, an additional 12/105 (11.4%) Abs-S seropositive and Abs-N ser-onegative samples were detected and total seropositivity was estimated at 96.2% (101/105). The increased SARS-CoV-2 seropositivity detected in current seroepidemiology study illustrates a high exposure rate during BA.5 predominance period. These data could guide public health decisions regarding immunization strategies and protection measures.

It is estimated that almost 4% of all neonatal intensive care unit admissions are attributed to Candida spp. infections. Clinical diagnosis of invasive fungal infection (IFI) is not easy as signs and symptoms are commonly vague. Mannan antigen (MA) in neonates is not well studied and the aim of this study was to evaluate the use of MA (Platelia™ Candida Ag Plus kit, Bio-Rad) in a neonatal unit. This is a prospective case-control study, which compared the performance of MA between neonates who had rectal Candida colonization with non-colonized controls. We cultured 340 rectal swabs of neonates and 39 of them were positive for Candida albicans colonization. MA was checked in 25 C. albicans colonized and in 30 non-colonized neonates with similar postnatal age and gender distribution. During the hospitalization period there was not any IFI in the neonatal population. MA was negative in all non-colonized neonates (30/30, 100% specificity) and in 24 out of 25 colonized neonates (96% specificity). However, the one infant with positive rectal colonization and MA had recent Candida mucositis. The results indicate a high specificity of the assay even in neonates colonized with Candida. Further investigation in neonates with IFI is required in order to determine the sensitivity of the method.