Longitudinal Cardiac Evaluation of Children with Multisystem Inflammatory Syndrome (MIS-C) Following COVID-19 by Conventional and Speckle-Tracking Echocardiography

Multisystem inflammatory syndrome in children (MIS-C), is a rare but severe, hyperinflammatory complication of COVID-19, in which cardiovascular abnormalities are frequently detected. In this prospective study, we describe the echocardiographic findings in patients with MIS-C, with the use of conventional Echocardiography and Speckle-Tracking Echocardiography (STE) with Left Ventricular (LV) Global Longitudinal Strain (GLS) analysis, in the acute and follow-up phase. In total, 25 MIS-C patients [64% females, mean (± SD) age: 8.3 (± 3.72) years] were included. In the acute phase, median (IQR) Troponin and NT-proBNP and mean heart rate, were 8.07 (14.52) pg/mL, 2875.00 (7713.00) pg/mL, and 102.87 (± 22.96) bpm, respectively. Median (IQR) LV Ejection Fraction (LVEF) was 66 (8)% and LVEF impairment was detected in 2/25 (8%) patients. On follow-up (mean time interval:9.50 ± 4.59 months), heart rate was significantly lower, with a mean value of 90.00 (± 14.56) bpm (p-value = 0.017). Median (IQR) LVEF was 66.00 (6.70)% (p-value = 0.345) and all 25 participants had normal LVEF. In 14/25 patients, additional LV-GLS analysis was performed. During the acute phase, mean LV-GLS was - 18.02 (± 4.40)%. LV-GLS was abnormal in 6/14 patients (42.9%) and among them, only one patient had reduced LVEF. On follow-up (median (IQR) time interval:6.93 (3.66) months), mean LV-GLS was -20.31 (± 1.91)% (p-value = 0.07) and in 1/14 patient (7.1%), the LV-GLS impairment persisted. In conclusion, in the acute and follow-up phase, we detected abnormal LV-GLS values in some patients, in the presence of normal LVEF, indicating that STE-GLS is a valuable tool for identifying subclinical myocardial injury in MIS-C.

The Soluble Urokinase Plasminogen Activator Receptor as a Severity Biomarker in Children With Acute COVID-19 or Multisystem Inflammatory Syndrome

BACKGROUND

Elevated soluble urokinase plasminogen activator receptor (suPAR) has been associated with a poor prognosis in serious infections. The aim of this study was to evaluate the clinical value of suPAR in children with acute coronavirus disease 2019 (COVID-19) or multisystem inflammatory syndrome (MIS-C).

METHODS

Serum suPAR was measured using the suPARnostic AUTO Flex enzyme-linked immunosorbent assay in hospitalized children with COVID-19, MIS-C, bacterial pneumonia, and healthy controls.

RESULTS

A total of 211 children with a mean (±SD) age of 6.9 ± 4.96 years were tested; with COVID-19: 59 (28%), MIS-C: 36 (17%), pneumonia: 78 (37%) and healthy controls: 38 (18%). In the acute phase, the levels of suPAR (mean ± SD) were: MIS-C: 8.11 ± 2.80 ng/mL, COVID-19: 4.91 ± 1.90 ng/mL, pneumonia: 4.25 ± 1.44 ng/mL and controls: 2.09 ± 0.47 ng/mL ( P < 0.001). Children with acute COVID-19 and a severe or moderate clinical presentation had higher values than those with mild symptoms: 5.79 ± 1.58 versus 5.40 ± 1.94 versus 3.19 ± 0.73 ng/mL, respectively ( P < 0.001). In the MIS-C group, children hospitalized in the intensive care unit and in need of mechanical ventilation had higher suPAR than those who were not admitted to an intensive care unit: 9.32 ± 3.06 versus 7.13 ± 2.19 ng/mL, respectively ( P = 0.023). In children with COVID-19 or MIS-C, a correlation was detected between suPAR values and length of hospitalization ( rs = 0.418, P < 0.001).

CONCLUSIONS

The findings suggest that suPAR may be a valuable biomarker of disease severity in children with COVID-19 or MIS-C. This could facilitate the identification of children in need of intensive anti-inflammatory treatment, as it has been shown in adults with severe COVID-19.

SARS-CoV-2 seroprevalence among children in Greece during Omicron variant period

The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. This study aims to evaluate SARS-CoV-2 seroprevalence in children during the different variants' subperiods. A prospective multicenter seroprevalence study was conducted in 7 University public hospitals in Greece from November 2021 to August 2022 (3 subperiods: November 2021-February 2022, March 2022-May 2022, June 2022-August 2022). Children from different age groups, admitted to the hospital or examined in outpatient clinics for reasons other than COVID-19 were enrolled. Neutralizing antibodies (Nabs), anti-Spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 IgG in serum were evaluated. A total of 2127 children (males:57,2%; median age:4,8years) were enrolled. Anti-N IgG seropositivity increased from 17,8% in the first sub-period to 40,7% in the second sub-period and then decreased in the third sub-period (36,7%). Anti-S IgG seropositivity appeared to have an increasing trend over the study period, starting from 34,8% and reaching 80,7%. Children aged 1-4 years old have significantly higher anti-N IgG titers compared to children aged 0-1 years old (p < 0,001). Infants have significantly lower anti-S IgG titers compared to all other age groups (p < 0,001). Immunocompromised children and infants have the lowest seropositivity for NAbs.Conclusions During the Omicron period, seropositivity significantly increased, as a result of higher transmissibility. Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1-4 years old present higher antibody titers, suggesting that this age group may mount a higher antibody response. Continuous surveillance seroprevalence studies are needed in children, in order to identify the true extent of SARS-CoV-2 and guide the planning of adequate public health measures.

Multisystem inflammatory syndrome in children (MIS-C): A nationwide collaborative study in the Greek population

Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe hyperinflammatory condition that may occur following SARS-CoV-2 infection. This retrospective, descriptive study of children hospitalized with multisystem inflammatory syndrome in children (MIS-C) in 12 tertiary care centers from 3/11/2020 to 12/31/2021. Demographics, clinical and laboratory characteristics, treatment and outcomes are described. Among 145 patients (95 males, median age 8.2 years) included, 123 met the WHO criteria for MIS-C, while 112 (77%) had serological evidence of SARS-CoV-2 infection. Fever was present in 99%, gastrointestinal symptoms in 77%, mucocutaneous involvement in 68% and respiratory symptoms in 28%. Fifty-five patients (38%) developed myocarditis, 29 (20%) pericarditis and 19 (13%) coronary aneurysms. Among the above cases 11/55 (20%), 1/29 (3.4%) and 5/19 (26.3%), respectively, cardiac complications had not fully resolved at discharge. Underlying comorbidities were reported in 18%. Median CRP value was 155 mg/l, ferritin 535 ng/ml, PCT 1.6 ng/ml and WBC 14.2 × 109/mm3. Most patients had elevated troponin (41.3%) and/or NT-pro-BNP (49.6%). Intravenous immunoglobulin plus corticosteroids were used in 117/145 (80.6%), monotherapy with IVIG alone in 13/145 (8.9%) and with corticosteroids alone in 2/145 (1.3%). Anti-IL1 treatment was added in 15 patients (10.3%). Thirty-three patients (23%) were admitted to the PICU, 14% developed shock and 1 required ECMO. Mortality rate was 0.68%. The incidence of MIS-C was estimated at 0.69/1000 SARS-CoV-2 infections. Patients who presented with shock had higher levels of NT-pro-BNP compared to those who did not (p < 0.001). Acute kidney injury and/or myocarditis were associated with higher risk of developing shock.

CONCLUSION

MIS-C is a novel, infrequent but serious disease entity. Cardiac manifestations included myocarditis and pericarditis, which resolved in most patients before discharge. Timely initiation of immunomodulatory therapy was shown to be effective. NT-pro-BNP levels may provide a better prediction and monitoring of the disease course. Further research is required to elucidate the pathogenesis, risk factors and optimal management, and long-term outcomes of this clinical entity.

WHAT IS KNOWN

• MIS-C is an infrequent but serious disease entity. • Patients with MIS-C present with multi-organ dysfunction, primarily involving the gastrointestinal and cardiovascular systems.

WHAT IS NEW

• NT-pro-BNP levels may provide a better prediction and monitoring of the disease course. • Acute kidney injury and/or myocarditis were associated with higher risk of developing shock.

Comparative Study of T-Cell Repertoires after COVID-19 Immunization with Homologous or Heterologous Vaccine Booster

Sequencing of the T-cell repertoire is an innovative method to assess the cellular responses after immunization. The purpose of this study was to compare T-cell repertoires after COVID-19 immunization with homologous (HOB) and heterologous (HEB) boosting. The study included 20 participants with a median age of 27.5 (IQR:23) years, who were vaccinated with one dose of the Ad26.COV2.S vaccine and were boosted with either Ad26.COV2.S (n = 10) or BNT162b2 (n = 10) vaccine. Analysis of the T-cell receptor beta locus (TCRβ) sequencing one month after the booster dose identified that the HEB compared to the HOB group exhibited a higher number of both total and COVID-19-related functional T-cell rearrangements [mean of total productive rearrangements (TPRs): 63151.8 (SD ± 18441.5) vs. 34915.4 (SD ± 11121.6), p = 0.001 and COVID-19-TPRs: 522.5 (SD ± 178.0) vs. 298.3 (SD ± 101.1), p = 0.003]. A comparison between the HOB and HEB groups detected no statistically significant differences regarding T-cell Simpson clonality [0.021 (IQR:0.014) vs. 0.019 (IQR:0.007)], richness [8734.5 (IQR:973.3) vs. 8724 (IQR:383.7)] and T-cell fraction [0.19 (IQR:0.08) vs. 0.18 (IQR:0.08)]. HEB also exhibited a substantially elevated humoral immune response one month after the booster dose compared to HOB [median antibody titer (IQR): 10115.0 U/mL (6993.0) vs. 1781.0 U/mL (1314.0), p = 0.001]. T-cell repertoire sequencing indicated that HEB had increased SARS-CoV-2-related T-cell rearrangements, which was in accordance with higher humoral responses and possibly conferring longer protection. Data from the present study indicate that the administration of different COVID-19 vaccines as a booster may provide better protection.

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-α2 in 10 patients: IFN-α2 only in three, IFN-α2 plus IFN-ω in five, and IFN-α2, IFN-ω plus IFN-β in two; IFN-ω only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-α2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-ω in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-α2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-ω only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-ω and/or IFN-α2.

Evaluation of the mannan antigen assay in neonates with or without Candida albicans colonization

Mannan antigen (MA) in neonates as a marker of invasive candidemia is not well studied, although 4% of all neonatal intensive care unit admissions are attributed to Candida spp. infections. The aim of this case-control study was to evaluate the performance of MA (Platelia™ Candida AgPluskit, Bio-Rad) in neonates who had rectal Candida colonization or in non-colonized controls. We cultured 340 rectal swabs of neonates and MA was negative in 24/25 C. albicans colonized (96% specificity) and in 30/30 non-colonized neonates (100% specificity). The results indicate a high specificity of the assay, which could be useful in neonates with possible candidemia.

Seroprevalence of Measles in Pairs of Mothers and Newborns in Southern Greece

Maternal immunoglobulin G (IgG) antibodies that are passively transferred to newborns through the placenta confer protection if they are exposed to measles virus. A measles outbreak occurred in several European countries including Greece, between 2016 and 2018. A prospective study was conducted in the General Hospital of Lakonia, regarding the measles seropositivity status of mother and newborn pairs. IgG antibody titer for measles was measured in serum samples acquired from pairs of mothers and newborns. The samples were analyzed through quantitative enzyme-linked immunosorbent assay, and antimeasles IgG >200 IU/mL was considered to be protective. Demographic data for mothers and neonates and data regarding immunization status of mothers were analyzed. Study population included 206 mothers and their newborns. In total, 12.6% of mothers (n = 26) and 10.7% of newborns (n = 22) did not have protective serology. A statistically significant positive linear association between maternal and neonatal antibodies was found (rho = 0.924) (p = 0.001). Neonates whose mothers were seropositive had higher antibodies [geometric mean concentration (GMC): 804.8 (728.3-889.2)] than neonates whose mothers were seronegative/borderline [GMC: 97.7 (64.2-148.8)] (p = 0.001). In the study area, a significant rate of mothers and newborns was found to have nonprotective measles serology that exceeds the limit required for herd immunity. Vaccination coverage in women of reproductive age should be increased to reduce potential for future measles epidemics.

Aquagenic wrinkling of the palms in a cohort of Greek children diagnosed with cystic fibrosis: Associated clinical parameters

BACKGROUND

Aquagenic wrinkling of the palms (AWP) is an excessive and early palmar wrinkling occurring after brief immersion to water (BIW), and has been reported as a frequent finding among Cystic Fibrosis (CF) patients.

OBJECTIVES

To investigate any associations of CF patients presenting AWP with other disease characteristics and explore the pathomechanism of AWP phenomenon.

METHODS

We evaluated AWP in CF patients and assessed the AWP parameters of palmar wrinkling, oedema, papules, pruritus and pain at 3, 7 and 11 min after a BIW test with other disease characteristics. Statistical analyses explored the associations of AWP with genotype, lung function, pancreatic insufficiency, hyperhidrosis, personal and family history of atopy and sweat chloride levels.

RESULTS

One hundred CF patients (mean age 10.4 years) were included in the analysis. The genotypic distribution was ΔF508/ΔF508: 47%, ΔF508/other: 41% and other/other: 12%. Statistically significant associations of Kaplan-Meier curves of the AWP parameters with various disease characteristics and personal/family history were detected. Wrinkling was associated with history of atopy, hyperhidrosis and levels of sweat chloride test. The time to presentation of oedema and the appearance of papules were associated with history of hyperhidrosis and age at diagnosis. Finally, time to appearance of pruritus was related to history of atopy and of hyperhidrosis. Regarding TEWL regression analysis showed significant associations with age at diagnosis (p = 0.024), sweat chloride test levels (p = 0.005), history of hyperhidrosis (p = 0.033), history of atopy (p = 0.002) and hepatic-pancreatic involvement (p = 0.027).

CONCLUSIONS

The existence of a statistically significant association between AWP and the history of hyperhidrosis, atopy, sweat chloride levels and hepatic-pancreatic function in CF patients was detected. A strong association between AWP and CF was detected. AWP after BIW could be elicited easily and possibly can be used as an initial screening tool to diagnose an individual with symptoms and signs that raise the likelihood of CF.

Kinetics of SARS-CoV-2 Spike Antibodies after the Second and Third Dose of the BNT162b2 COVID-19 Vaccine and Association with Epidemiological Characteristics and Breakthrough Infection in a Cohort Study of Healthcare Workers

To prospectively study the kinetics of immune responses after immunization with the BNT162b2 mRNA COVID-19 vaccine and their association with epidemiological parameters and breakthrough infection (BI), we measured total (TAbs-WT) and neutralizing antibodies against wild-type (NAbs-WT) and Omicron (NAbs-O) SARS-CoV-2 spike proteins in healthcare workers (HCWs) after the second (4 and 8 months) and third dose (1 and 8 months). Vaccinated HCWs (n = 486), with a median age (IQR) of 49 years (38-56), were included in this prospective cohort study. BI was observed 4 and 8 months after the second dose in 8/486 (1.6%) and 15/486 (3.1%) HCWs, respectively, and 1 and 8 months after the third dose in 17/486 (3.5%) and 152/486 (31.3%) HCWs, respectively. A comparison of immune responses 1 month after the third dose in vaccinated HCWs without a BI or with a BI in the next 7 months did not detect any statistically significant differences in the TAbs-WT (median (IQR): 16,611.0 (13,011.0) U/mL vs. 17,572.5 (14,501.0) U/mL, p = 0.529) and NAbs-WT (median (IQR): 96.5% (1.7) vs. 96.7% (1.9), p = 0.555). After infection, HCWs with a BI had significantly increased TAbs-WT levels at all time points compared to healthy HCWs. The findings of the present study indicate that antibody levels after three doses of the BNT162b2 vaccine are not directly associated with the possibility of a BI.

Epidemiological study of unusual rotavirus strains and molecular characterization of emerging P[14] strains isolated from children with acute gastroenteritis during a 15-year period

Rotavirus group A (RVA) is characterized by molecular and epidemiological diversity. To date, 42 G and 58 P RVA genotypes have been identified, some of which, like P[14], have a zoonotic origin. In this study, we describe the epidemiology of unusual RVA genotypes and the molecular characteristics of P[14] strains. Fecal samples from children ≤ 16 years of age with acute gastroenteritis (AGE) who were hospitalized during 2007-2021 in Greece were tested for RVA by immunochromatography. Positive RVA samples were G and P genotyped, and part of the VP7 and VP4 genes were sequenced by the Sanger method. Epidemiological data were also recorded. Phylogenetic analysis of P[14] was performed using MEGA 11 software. Sixty-two (1.4%) out of 4427 children with RVA AGE were infected with an unusual G (G6/G8/G10) or P (P[6]/P[9]/P[10]/P[11]/P[14]) genotype. Their median (IQR) age was 18.7 (37.3) months, and 67.7% (42/62) were males. None of the children were vaccinated against RVA. P[9] (28/62; 45.2%) was the most common unusual genotype, followed by P[14] (12/62; 19.4%). In the last two years, during the period of the COVID-19 pandemic, an emergence of P[14] was observed (5/12, 41.6%) after an 8-year absence. The highest prevalence of P[14] infection was seen in the spring (91.7%). The combinations G8P[14] (41.7%), G6P[14] (41.7%), and G4P[14] (16.6%) were also detected. Phylogenetic analysis showed a potential evolutionary relationship of three human RVA P[14] strains to a fox strain from Croatia. These findings suggest a possible zoonotic origin of P[14] and interspecies transmission between nondomestic animals and humans, which may lead to new RVA genotypes with unknown severity.

Serum YKL-40 as a Potential Biomarker for Sepsis in Term Neonates-A Pilot Study

Although YKL-40 is a promising diagnostic biomarker of sepsis in adults, its value in neonatal sepsis is not known. The study objectives included assessing the levels and diagnostic value of serum YKL-40 in term neonates with sepsis and comparing YKL-40 with other commonly used inflammatory biomarkers. In this pilot case-control study, 45 term neonates (30 septic and 15 non-septic, as controls), 4 to 28 days old, were prospectively studied. The International Pediatric Sepsis Consensus Conference criteria were applied to diagnose sepsis. During the acute phase (admission) and remission of sepsis, blood samples were collected from cases (while from controls they were only collected once) for routine laboratory tests, cultures, and the measurement of serum YKL-40 levels via Elisa. In the acute phase of sepsis, YKL-40 levels were significantly elevated in comparison with remission (p = 0.004) and controls (p = 0.003). YKL-40 levels did not differ significantly between patients in remission and controls (p = 0.431). Upon admission, YKL-40 levels correlated positively with white blood count, absolute neutrophil count, and CRP levels. Via ROC analysis, it was shown that YKL-40 levels upon admission were a significant indicator of sepsis (AUC = 0.771; 95% CI 0.632-0.911; p = 0.003). Serum YKL-40 might be considered as an adjuvant biomarker of sepsis in term neonates.

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

Immune responses following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children are still under investigation. Even though coronavirus disease 2019 (COVID-19) is usually mild in the pediatric population, some children exhibit severe clinical manifestations, require hospitalization, or develop the most severe condition: a multisystem inflammatory syndrome in children (MIS-C) associated with SARS-CoV-2 infection. The activated innate, humoral and T-cell-mediated immunological pathways that lead certain pediatric populations to present with MIS-C or remain asymptomatic after SARS-CoV-2 infection are yet to be established. This review focuses on the immunological aspects of MIS-C with respect to innate, humoral, and cellular immunity. In addition, presents the role of the SARS-CoV-2 Spike protein as a superantigen in the pathophysiological mechanisms, discusses the great heterogeneity among the immunological studies in the pediatric population, and highlights possible reasons why some children with a certain genetic background present with MIS-C.

Supplementation of Mother's Own Milk with Preterm Donor Human Milk: Impact on Protein Intake and Growth in Very Low Birth Weight Infants-A Randomized Controlled Study

This randomized study investigates whether feeding very low birth weight (VLBW) infants with mother's own milk (MOM) supplemented with either preterm (PDM) or term donor milk (TDM), when MOM is insufficient, has a positive impact on infants' protein intake and growth. A hundred and twenty VLBW infants were randomized into two groups. Group A (43 infants) received MOM supplemented with PDM, whereas Group B (77 infants) was fed with MOM supplemented with TDM, for the first three weeks of life (donor milk period). Breast milk fortifier was added when milk feeds exceeded 50 mL/Kg/day. After the donor milk period, both groups were fed with formula when MOM was not available or the milk bank was unable to provide TDM. Protein intake was higher in Group A than in Group B at initiation of milk fortification (p = 0.006), as well as during the 3-week donor milk period (p = 0.023) and throughout hospitalization (p = 0.014). Moreover, Group A presented higher Δz-score for body weight (p = 0.019) and head circumference (p = 0.001) from birth to the end of donor milk period, and higher mean body weight at discharge (p = 0.047) compared to Group B. In conclusion, when donor milk is required, PDM positively impacts protein intake and growth in VLBW infants (NCT05675397).

Seroprevalence of anti-SARS-CoV-2 antibodies among children and their parents in Greece

School closures were enforced as measures to restrain the COVID-19 pandemic, based on the assumption that young children may play a key role in SARS-CoV-2 spread. This study aims to determine the prevalence of SARS-CoV-2 IgG antibodies in children and corresponding parents, in order to improve surveillance and estimate the prevalence of asymptomatic or subclinical COVID-19 cases. A prospective multicenter study was conducted between March and June 2021 in Greece. Children admitted to the hospital or examined in outpatient clinics for reasons other than COVID-19 and their parents were tested for anti-Spike SARS-CoV-2 IgG in serum. A questionnaire about clinical and demographic data was completed. The study included 823 participants: 427 children and 396 corresponding parents. The overall seroprevalence was 16.4% in parents and 13.8% in children. Among families with ≥ 1 seropositive child or parent, the combination of a seropositive parent and a corresponding seronegative child was 29.6%, a seronegative parent and a corresponding seropositive child was 24.7%, and a seropositive child with a corresponding seropositive parent was 45.7%. Age, level of education, and school or work attendance were not significantly associated with increased seropositivity. On the contrary, ethnic minority of Roma, close contact with known COVID-19 case, previous symptoms consistent with COVID-19, and mass gatherings were risk factors for seropositivity.

CONCLUSION

The spread of SARS-CoV-2 during a period of lockdown in Greece was low in children and comparable to adults most likely due to intrafamilial transmission. Accordingly, it is unlikely that children have boosted virus transmission.

WHAT IS KNOWN

• In the earliest months of the pandemic, it was demonstrated that children had significantly lower seroprevalence rates than the older age groups, due to the fact that children had decreased exposure to the virus, because of early public health interventions, such as school and day care closure. • Later, further studies reported that children have similar incidence rate of SARS-CoV-2 infection compared to adults in households and community settings.

WHAT IS NEW

• In this seroprevalence study, the spread of SARS-CoV-2 infection during a period of lockdown in Greece with the predominance of the Alpha-variant was particularly low in children and comparable to adults, most likely due to intrafamilial transmission. • These study findings will be useful for decisions regarding non-pharmaceutical interventions during the pandemic, and especially, to guide in designing and implementing appropriate containment measures for schools and social gatherings.

1093. Multiparametric Investigation Of Spike-Protein Specific T-cell Cytokine Expression Profile In Children With Symptomatic COVID-19 Or Multisystem Inflammatory Syndrome

Background

Data regarding cell-mediated immunological differences in children across COVID-19 clinical spectrum are limited. We prospectively investigated Spike-protein specific cellular immunity in children with symptomatic COVID-19 or MIS-C, by single cell cytokine expression profiling.

Methods

PBMCs from children with MIS-C, symptomatic COVID-19 (one month after hospitalization) and healthy controls were isolated prospectively. Cell suspensions were divided into two quantitatively equal samples (a negative control-unstimulated and a positive-stimulated). Cells stimulation was performed using SARS-CoV-2 Spike antigenic peptides mix (Peptivator SARS-CoV-2 Prot_S). Cells of each sample were stained with fluorochrome monoclonal antibodies against 8 surface markers (CD3, CD4, CD8, CD14, CD19, CD137, CD197, CD45RA) and 6 intracellular markers (IL-4, IL-2, IL-17, IFN-γ, TNF-α, Granzyme B). Viability was assessed by 7AAD. Stained cell preparations were analysed using 13 colour Flow Cytometry (DX Flex, Beckman Coulter). Flow cytometric analysis was performed using Kaluza 2.1 Software.

Results

Sixteen children (4 MIS-C, 8 post-COVID-19 and 4 healthy controls) were included in the study. The mean age (±SD) of the participants was 11.22 years (±3.48). Children with MIS-C had significantly higher mean (±SD) values of CD8+IFN-γ/million CD3+ [226.68 (134.92) vs 45.43 (57.28); P: 0.033] and median (IQR) of CD8+IFN-γ/ml [156.38 (184.13) vs 26.34 (82.36);P: 0.033] compared to symptomatic COVID-19 children. Compared to healthy controls, MIS-C patients had significantly higher median (IQR) values of CD4+IL-2/million CD3+ [923.12 (3777.95) vs 97.59 (71.71); P: 0.042] and CD4+IL-2/ml median (IQR) [626.33 (2744.98) vs 169.3 (173.91); P: 0.042]. No other significant differences were observed regarding other immunological markers in 3 study groups.

Conclusion

IFN-γ production by CD8+ T cells is highly expressed in children with MIS-C compared to hospitalized children one month after acute COVID-19 and could consist possible immunological biomarker. Further studies are needed in order to elucidate the pathophysiological basis of these findings.

Disclosures

All Authors: No reported disclosures.

Rotavirus epidemiology and genotype distribution in hospitalised children, Greece, 2008 to 2020: A prospective multicentre study

BackgroundTwo rotavirus (RV) vaccines were licensed in Greece in late 2006 and included in the national immunisation programme in 2012.AimTo study the epidemiology and genotype distribution of RV in children during the post-vaccination period and assess the impact of increased vaccination coverage.MethodsIn a prospective multicentre hospital-based study, hospitalised children (≤ 16 years) with an RV-positive faecal sample were recruited. Epidemiological and genotyping analyses were performed; periods of low (2008-12) and moderate (2012-20) RV vaccination coverage were compared. Statistical analysis was performed with a chi-squared or Mann-Whitney U test and logistic regression.ResultsA total of 3,874 children (55.6% male; n = 2,153) with median age of 1.4 years (IQR: 0.5-3.3) were studied during 2008-20. Most RV-infected children were aged ≤ 3 years (72.2%) and hospitalised during December-May (69.1%). Common RV genotypes (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], G12P[8]) were detected in 92.2% of samples; G-P combinations with prevalence above 1% were G4P[8] (44.1%), G1P[8] (25.4%), G2P[4] (14.9%), G9P[8] (3.5%), G12P[8] (2.2%), G3P[8] (2.1%), other (4.3%) and mixed (3.5%). Of all samples, 97.6% were homotypic or partially heterotypic to vaccines' genotypes. With moderate vaccination coverage, the seasonal peak was detected earlier, children were older and partially or fully heterotypic genotypes were increased (p < 0.001).ConclusionsIn the era of moderate RV vaccination coverage in Greece, epidemiology of RV in hospitalised children seemed to change. However, most circulating genotypes remain homotypic or partially heterotypic to RV vaccines. Continuous epidemiological surveillance and genotyping are important to monitor possible changes arising from RV vaccines' implementation.

Rotavirus epidemiology and genotype distribution in hospitalised children, Greece, 2008 to 2020: A prospective multicentre study

BackgroundTwo rotavirus (RV) vaccines were licensed in Greece in late 2006 and included in the national immunisation programme in 2012.AimTo study the epidemiology and genotype distribution of RV in children during the post-vaccination period and assess the impact of increased vaccination coverage.MethodsIn a prospective multicentre hospital-based study, hospitalised children (≤ 16 years) with an RV-positive faecal sample were recruited. Epidemiological and genotyping analyses were performed; periods of low (2008-12) and moderate (2012-20) RV vaccination coverage were compared. Statistical analysis was performed with a chi-squared or Mann-Whitney U test and logistic regression.ResultsA total of 3,874 children (55.6% male; n = 2,153) with median age of 1.4 years (IQR: 0.5-3.3) were studied during 2008-20. Most RV-infected children were aged ≤ 3 years (72.2%) and hospitalised during December-May (69.1%). Common RV genotypes (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], G12P[8]) were detected in 92.2% of samples; G-P combinations with prevalence above 1% were G4P[8] (44.1%), G1P[8] (25.4%), G2P[4] (14.9%), G9P[8] (3.5%), G12P[8] (2.2%), G3P[8] (2.1%), other (4.3%) and mixed (3.5%). Of all samples, 97.6% were homotypic or partially heterotypic to vaccines' genotypes. With moderate vaccination coverage, the seasonal peak was detected earlier, children were older and partially or fully heterotypic genotypes were increased (p < 0.001).ConclusionsIn the era of moderate RV vaccination coverage in Greece, epidemiology of RV in hospitalised children seemed to change. However, most circulating genotypes remain homotypic or partially heterotypic to RV vaccines. Continuous epidemiological surveillance and genotyping are important to monitor possible changes arising from RV vaccines' implementation.

Time of Day of BNT162b2 COVID-19 Immunization Affects Total SARS-CoV-2 Antibody Levels but Not Neutralizing Activity

To examine whether immunization time affects the immune responses elicited by the BNT162b2 COVID-19 vaccine, we investigated the possible association between total SARS-CoV-2 spike protein receptor binding domain (TAbs-RBD) and neutralizing (NAbs-RBD) antibodies with vaccination time. A cohort of 468 healthcare workers (mean age [±SD]: 48 [±13] years), were included in the study. One month after the second dose, healthcare workers who were vaccinated between 1500-2200 h had higher TAbs-RBD compared to 0700-1100 h and 1100-1500 h (p = 0.006). One month after the third dose, healthcare workers who were vaccinated between 0700-1100 h and 1500-2200 h had significantly higher TAbs-RBD compared to 1100-1500 h (p = 0.034). However, no association of NAbs-RBD with vaccination time was detected after each of the 3 doses (p > 0.4). Despite the possible effect of BNT162b2 vaccination time in TAbs-RBD levels, possibly due to rhythmic expression of clock genes, neutralizing activity was not associated with vaccination time and, therefore, further investigation is required.

Post‑COVID‑19 syndrome in children (Review)

The persistence of symptoms for a long time after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is now familiar as post-COVID syndrome (PCS). To the best of our knowledge, the risk of long-term clinical outcomes in children after SARS-CoV-2 infection is still unclear. Unlike in adults, current evidence suggests a lower prevalence of persistent symptoms in children. However, since several studies are characterized by great heterogeneity, it is difficult to accurately estimate the exact incidence of PCS in children. The presence and course of recovery depend on risk factors that are more common in adults than children. Proposed pathophysiological mechanisms in PCS in children include age-dependent immune responses, angiotensin-converting enzyme 2 expression, blood-brain barrier development or social issues affecting children behavior, such as school closure and social isolation. However, further longitudinal studies are required for unanswered issues to be clarified. The aim of the present review is to describe the long-term symptoms per biological system in children, potential risk factors and the role of the immune system in the presence of PCS.

Coagulation Abnormalities and Management in Hospitalized Pediatric Patients With COVID-19

BACKGROUND

The incidence and severity of coagulation abnormalities have not been extensively studied in pediatric populations with coronavirus disease 2019 (COVID-19). Moreover, their association with an increased risk for thromboembolic events remains unclear, and there is a lack of evidence for optimal prophylactic antithrombotic management. The aim of our study was to present our experience in evaluation, management, and long-term outcomes of coagulation abnormalities in pediatric hospitalized patients with COVID-19.

METHODS

A prospective study was performed in all children hospitalized for COVID-19 during a 6-month period focusing on patients' coagulation abnormalities, the normalization of the coagulation profile with or without anticoagulation prophylaxis and the clinical outcome of the disease.

RESULTS

Two hundred twenty-three patients (median age: 11.4 months) were enrolled in the study. Coagulation abnormalities were detected in 92.4% of patients with increased D-dimer levels to be the most common abnormality detected in 84.3% of patients. Prophylactic anticoagulation was initiated only in 7 (3.1%) selected patients with severe COVID-19 and at least 2 risk factors for venous thromboembolism (VTE) and in all patients with previous history of VTE. Follow-up coagulation profile in 85 patients showed that changes over time had a tendency towards normalization irrespectively of the initiation of anticoagulant thromboprophylaxis. No thrombotic complications were observed 3 months upon discharge.

CONCLUSIONS

Although abnormal findings in coagulation profile were very common, they were not associated with risk for VTE even in severe cases. A trend of normalization early in the course of the disease was observed regardless of the use of anticoagulant thromboprophylaxis.

Rhabdomyolysis and coronavirus disease‐2019 in children: A case report and review of the literature

Introduction

Coronavirus disease‐2019 (COVID‐19) presents with a variety of symptoms, but rhabdomyolysis has rarely been reported in children.

Case presentation

We report a 10‐year‐old girl who presented with fever, myalgia, and limping. The patient was tested positive for severe acute respiratory syndrome coronavirus‐2. On admission, creatine kinase (CK) level was 13 147 units per liter and the patient was diagnosed with rhabdomyolysis. She was treated with intravenous fluids, which resulted in CK levels decrease. There are currently seven case reports of children with rhabdomyolysis associated with acute COVID‐19 infection and two reports with the multisystemic inflammatory syndrome.

Conclusion

Children presenting with muscle pain and weakness in the acute phase or following COVID‐19 infection, should alert physicians of the possibility of rhabdomyolysis.

Seroepidemiology of SARS-CoV-2 in pediatric population during a 16-month period prior to vaccination

Limited prospective serosurveillance data in children regarding severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection have been reported. We prospectively investigated SARS‐CoV‐2 seropositivity in children during a 16‐month period of the coronavirus disease 2019 (COVID‐19) pandemic, including the four waves of the pandemic, before SARS‐CoV‐2 adolescents' vaccination. Serum samples from children admitted to the major tertiary Greek pediatric hospital for any cause, except for COVID‐19 infection, were randomly collected from 05/2020 to 08/2021. The study period was divided into four 4‐month periods representing relevant epidemic waves. Total SARS‐CoV‐2 antibodies for nucleocapsid protein were determined using the Elecsys® Anti‐SARS‐CoV‐2 reagent. A total of 3099 children (0–16 years) were included in the study. A total of 344 (11.1%) seropositive children were detected (males: 205 [59.5%]; median age [interquartile range [IQR]]: 3 years [0.6–10]). Seropositivity rates (%) increased during the four 4‐month periods: 1.4%, 8.6%, 17.2%, and 17.6%, respectively. A correlation of seropositivity rates in children with new diagnosed SARS‐CoV‐2 cases in the community was detected. No significant differences were detected between males and females. Seropositivity was significantly higher in hospitalized than in nonhospitalized children and in non‐Greek compared to Greek children (p < 0.001). The lowest seropositivity rate before school opening (9/2021) was detected in the age groups 6–12 years (14.4%) and 12–16 years (16.1%). However, compared with the other age groups, the lowest median antibody titers were observed in children 0–1 year (median [IQR]: 13.9 cut‐off index: [4.5–53.9] [p < 0.001]). Although the seropositivity of children was related to the community epidemic waves, the exposure was limited. Low seropositivity rates in school‐age children support the need for SARS‐CoV‐2 immunization.

SARS‐CoV‐2 seropositivity rates (%) in children residing in Athens increased from 05/2020 to 08/2021 during the four 4‐month pandemic waves: 1.4%, 8.6%, 17.2%, and 17.6%, respectively.

A correlation of seropositivity rates in children with new diagnosed SARS‐CoV‐2 cases in the community was detected.

The lowest seropositivity rate before school opening (9/2021) was detected in the age groups 6–12 years (14.4%) and 12–16 years (16.1%).

Limited exposure and low seropositivity rates in school‐age children support the need for SARS‐CoV‐2 immunization.

Association of clinical and epidemiological characteristics with COVID-19 BNT162b2 mRNA vaccine short-term adverse reactions in healthcare workers

INTRODUCTION

The aim of the study was to investigate the prevalence and severity of adverse reactions (ARs) after immunization of healthcare workers (HCWs) with BNT162b2 vaccine and to associate them with clinical and epidemiological characteristics.

METHODS

A form containing demographic and clinical data as well as ARs after both doses of the vaccine was completed, and statistical association analysis was performed.

RESULTS

A total of 502 HCWs (females 78.3%) with mean age (±SD) 48.17 years (±12.97) participated. After the first dose, 404 (80.5%) HCWs reported at least one local AR (LAR) and 366 (72.9%) after the second dose (p-value=0.004). After the first dose, 121 (24.1%) HCWs reported at least one systemic AR (SAR) and 275 (54.8%) after the second dose (p-value<0.0001).In the logistic regression analysis, there was no association of gender or medical history of underlying disease with LARs. There was a negative association of age with the cumulative score (CS) of LARs (OR: 0.82, 95% CI: 0.69-0.96) after the first dose. Females had a positive association with CS of SARs following both doses (OR, 95% CI: 2.57, 1.39-4.73 and 2.71, 1.76-4.19, respectively). Age was negatively associated with CS of SARs (OR: 0.66, 95% CI: 0.57-0.76) after the second dose. Severe ARs included Bell's palsy (1) and tinnitus with temporary hearing loss (1).

CONCLUSION

The administration of the BNT162b2 vaccine in our HCWs cohort had a good safety profile with the most common ARs being self-limited. An increasing rate of SARs following the second vaccine dose was noticed. Rare but severe possible ARs should be further investigated.

SARS-CoV-2 variants and effectiveness of vaccines: a review of current evidence

The SARS-CoV-2 virus is rapidly evolving via mutagenesis, lengthening the pandemic, and threatening the public health. Until August 2021, 12 variants of SARS-CoV-2 named as variants of concern (VOC; Alpha to Delta) or variants of interest (VOI; Epsilon to Mu), with significant impact on transmissibility, morbidity, possible reinfection and mortality, have been identified. The VOC Delta (B.1.617.2) of Indian origin is now the dominant and the most contagious variant worldwide as it provokes a strong binding to the human ACE2 receptor, increases transmissibility and manifests considerable immune escape strategies after natural infection or vaccination. Although the development and administration of SARS-CoV-2 vaccines, based on different technologies (mRNA, adenovirus carrier, recombinant protein, etc.), are very promising for the control of the pandemic, their effectiveness and neutralizing activity against VOCs varies significantly. In this review, we describe the most significant circulating variants of SARS-CoV-2, and the known effectiveness of currently available vaccines against them.

Association of total and neutralizing SARS-CoV-2 spike -receptor binding domain antibodies with epidemiological and clinical characteristics after immunization with the 1st and 2nd doses of the BNT162b2 vaccine

Background

Data regarding the association of antibody levels elicited after immunization with the BNT162b2 mRNA COVID-19 vaccine with epidemiological and clinical parameters are limited.

Methods

We prospectively measured the total (TAbs-RBD) and the neutralizing antibodies (NAbs-RBD) against the receptor binding domain (RBD) of SARS-CoV-2 spike protein in a cohort of 268 Healthcare workers before immunization, 20 days after the 1^st dose and 30 days after the 2^nd dose of the BNT162b2 vaccine. A statistical analysis for possible association of antibodies’ levels with epidemiological and clinical parameters was performed.

Results

The mean age (±SD) of the participants was 45.45 years (±11.93) (range: 24–70 years) and 211 (79.9%) were females. Statistically significant differences were detected regarding both TAbs-RBD and NAbs-RBD between the first and second doses of the vaccine (P < 0.001). The median (IQR) percentage (%) of NAbs-RBD after the 1^st dose was 51.07% (31.60%) and after the 2^nd dose 95.31% (3.70%) (P < 0.001). The correlation between the TAbs-RBD and NAbs-RBD was after the 1^st dose, Spearman’s, rho: 0.861 (P < 0.001) and after the 2^nd dose rho: 0.989 (P < 0.001). Twenty days after the 1^st dose, 56/264 (21.2%) of the participants had low levels of NAbs-RBD, while one month after the 2^nd dose all of them had protective levels of NAbs-RBD. After the 2^nd vaccine dose, a statistically significant negative association of TAbs-RBD was detected for age (P < 0.001), smoking (P = 0.011), and immunosuppressive medications (P < 0.001), while a positive association was detected for BMI (P = 0.004) and systemic adverse events after immunization (P = 0.001).

Conclusion

A significant correlation of TAbs-RBD and NAbs-RBD was detected after both vaccine doses. Older age, smoking, and immunosuppressive medications negatively affected the final antibody level after SARS-CoV-2 immunization. Our findings emphasize the significance of the 2^nd vaccine dose especially in the older age groups.

Clinical characteristics of COVID-19 in neonates and young infants

We report the clinical characteristics and management of fourteen neonates and very young infants with COVID-19. Although all presented with mild symptoms and did not require specific treatment, most of them had abnormal laboratory and radiological findings. Ten infants presented with neutropenia and/or monocytosis but none with lymphopenia. Transient hypertriglyceridemia and/or prolonged viral shedding were detected in 9 patients.Conclusion: Based to our experience, COVID-19 is mild in very young infants and might have distinct laboratory findings. What is Known: • SARS-CoV-2 in infants is a mild disease. • The period of transmission is approximately 2 weeks. What is New: • Very young age is not a risk factor for severe COVID-19 but could be associated with prolonged viral shedding. • Neutropenia and monocytosis are distinct characteristics of COVID-19 in very young infants.

Immune response to SARS-CoV-2 in children: A review of the current knowledge

Host immune responses to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), especially in children, are still under investigation. Children with coronavirus disease 2019 (COVID‐19) constitute a significant study group of immune responses as they rarely present with severe clinical manifestations, require hospitalization, or develop complications such as multisystem inflammatory syndrome in children (MIS‐C) associated with SARS‐CoV‐2 infection. The deciphering of children’s immune responses during COVID‐19 infection will provide information about the protective mechanisms, while new potential targets for future therapies are likely to be revealed. Despite the limited immunological studies in children with COVID‐19, this review compares data between adults and children in terms of innate and adaptive immunity to SARS‐CoV‐2, discusses the possible reasons why children are mostly asymptomatic, and highlights unanswered or unclear immunological issues. Current evidence suggests that the activity of innate immunity seems to be crucial to the early phases of SARS‐CoV‐2 infection and adaptive memory immunity is vital to prevent reinfection.

Despite the limited immunological studies from children with COVID‐19, this review compares data between adults and children in terms of innate and adaptive immunity to SARS‐CoV‐2, discusses the possible reasons why children are mostly asymptomatic, and highlights unanswered or unclear immunological issues.

The Emerging Role of Sfrp5 and Wnt5a in the Pathogenesis of Obesity: Implications for a Healthy Diet and Lifestyle

In recent decades, the prevalence of obesity has risen dramatically worldwide among all age groups. Obesity is characterized by excess fat accumulation and chronic low-grade inflammation. The adipose tissue functions as a metabolically active endocrine organ secreting adipokines. A novel duo of adipokines, the anti-inflammatory secreted frizzled-related protein 5 (Sfrp5) and the proinflammatory wingless type mouse mammary tumor virus (MMTV) integration site family member 5A (Wnt5a), signal via the non-canonical Wnt pathway. Recent evidence suggests that Sfpr5 and Wnt5a play a key role in the pathogenesis of obesity and its metabolic complications. This review summarizes the current knowledge on the novel regulatory system of anti-inflammatory Sfrp5 and pro-inflammatory Wnt5a, and their relation to obesity and obesity-related complications. Future studies are required to investigate the potential role of Sfrp5 and Wnt5a as biomarkers for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors. These adipokines may also serve as novel therapeutic targets for obesity-related disorders.

A toddler diagnosed with severe postinfectious bronchiolitis obliterans and COVID-19 infection

During the COVID-19 pandemic, management of SARS-CoV-2 infection in children with underlying chronic lung disease has been challenging. There are limited studies in children with respiratory comorbidities, apart from asthma, presumably due to low morbidity of SARS-CoV-2 infection in the general pediatric population along with the low incidence of certain pulmonary conditions. Compassionate use of remdesivir has been shown to reduce time to clinical improvement in adults and has been retrospectively studied in small pediatric cohorts with promising results. Whether children with underlying respiratory conditions may benefit from antiviral treatment in the context of different pathophysiologic backgrounds and unknown drug safety and efficacy needs to be further evaluated. We present a case of COVID-19 infection in a 3-year old toddler with severe postinfectious bronchiolitis obliterans, who received compassionate treatment with 5-day-course of remdesivir, and recovered with favourable outcome.

Aquagenic wrinkling of the palms after brief immersion to water test as a screening tool for cystic fibrosis diagnosis

BACKGROUND

Aquagenic wrinkling of the palms (AWP) is an excessive and early palmar wrinkling occurring after Brief Immersion to Water (BIW), and has been reported as a frequent finding among cystic fibrosis (CF) patients.

OBJECTIVES

To evaluate and assess the diagnostic performance of BIW test as an initial screening tool for CF diagnosis.

METHODS

We measured AWP in CF patients, CF-heterozygotes (CF-het) and normal controls. The AWP parameters of palmar wrinkling, oedema, papules, pruritus and pain were assessed at 3, 7 and 11 min after a BIW test was performed for all the participants. Statistical analyses explored the progression of AWP in time for the three groups and assessed the diagnostic performance of BIW test as a diagnostic screening tool for CF.

RESULTS

A total of 250 individuals (100 CF patients, their 50 CF-het parents, 100 healthy controls) were included in the analysis. The average age in years (mean ± SD) was 10.4 ± 4.0 for CF, 35.9 ± 6.1 for CF-het and 10.5 ± 4.0 for controls. The rate of positives for AWP at 3 min among CF patients, CF-het and controls was 68%, 8% and 0%, respectively (P < 0.01). Kaplan-Meier analysis showed a clear trend towards earlier appearance of all five parameters in the direction controls < hetCF < CF (P values <0.01). The best diagnostic performance in detecting between CF patients and non-CF was achieved by the presence of papules and wrinkling at 7 min (sensitivity/specificity: 94.0%/98.3% and 100.0%/92.0%, respectively).

CONCLUSIONS

A strong association between AWP and CF was detected. AWP after BIW could be elicited easily and possibly can be used as an initial screening tool to assess if an individual with symptoms and signs that raise the likelihood of CF is a CF patient.

The Effect of a Life-Style Intervention Program of Diet and Exercise on Irisin and FGF-21 Concentrations in Children and Adolescents with Overweight and Obesity

Overweight and obesity in childhood and adolescence represent major public health problems of our century, and account for increased morbidity and mortality in adult life. Irisin and Fibroblast Growth Factor 21 (FGF-21) have been proposed as prognostic and/or diagnostic biomarkers in subjects with obesity and metabolic syndrome, because they increase earlier than other traditional biomarkers. We determined the concentrations of Irisin and FGF-21 in children and adolescents with overweight and obesity before and after one year of a life-style intervention program of diet and physical exercise and explored the impact of body mass index (BMI) reduction on the concentrations of Irisin, FGF-21 and other cardiometabolic risk factors. Three hundred and ten (n = 310) children and adolescents (mean age ± SD: 10.5 ± 2.9 years) were studied prospectively. Following one year of the life-style intervention program, there was a significant decrease in BMI (p = 0.001), waist-to-hip ratio (p = 0.024), waist-to-height ratio (p = 0.024), and Irisin concentrations (p = 0.001), and an improvement in cardiometabolic risk factors. There was no alteration in FGF-21 concentrations. These findings indicate that Irisin concentrations decreased significantly as a result of BMI reduction in children and adolescents with overweight and obesity. Further studies are required to investigate the potential role of Irisin as a biomarker for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors.

Paraoxonase (PON)-1 activity in septic neonates: One more arrow in the quiver of biomarkers of neonatal sepsis?

Paraoxonase-1 (PON-1), a calcium ion-dependent high-density lipoprotein (HDL)-associated enzyme, has been proposed as a negative acute phase reactant biomarker in animal and human adult studies. The aim of this study was to evaluate the value of PON-1 activity in the diagnosis and monitoring of neonatal sepsis. Serum PON-1 activity, as paraoxonase and arylesterase, was prospectively studied in 48 septic neonates and matched controls. PON-1 activity was decreased at the acute phase of sepsis in comparison with values at recovery and values in controls. Paraoxonase or arylesterase at enrollment correlated significantly with serum Amyloid-A, CRP and IL-6 and could also discriminate septic than non-septic neonates. In conclusion, our results are promising regarding the role of PON-1 as a biomarker of neonatal sepsis. Larger studies are needed to validate the clinical utility of PON-1 in neonatal medicine.

Measles epidemic in pediatric population in Greece during 2017-2018: Epidemiological, clinical characteristics and outcomes

Background and aim

A measles outbreak occurred in Greece during 2017–2018 affecting mainly pediatric population. The aim of the study was to describe the epidemiological and clinical characteristics of the cases diagnosed in the major pediatric tertiary hospital of Athens, where 26.5% of national pediatric measles cases were diagnosed and treated.

Methods

This is a retrospective study of children 0–16 years old, who presented at the emergency department and/or were hospitalized with clinical presentation compatible with measles and diagnosis was confirmed with molecular detection of the measles RNA in pharyngeal swabs. Epidemiological, clinical and laboratory characteristics were retrieved from medical records and analyzed.

Results

A total of 578 children with measles were identified during the study period. 322 (55.7%) were male with median age 36 months (range:1–193), while the largest number of documented cases (251; 43.4%) were children aged 1–5 years. Most children (429/578; 74.2%) belonged to the Roma minority and only 64 (11.1%) had Greek origin. 497 (91.5%) children were unvaccinated and 37 (6.8%) were partially vaccinated with measles vaccine. Hospitalization was required for 342 (59.2%) children, whereas one or more complications were reported in 230 (67.2%) of them. Most frequent complications were elevated transaminases (139; 40.6%), acute otitis media (72; 21%), dehydration (67; 19.6%) and pneumonia (58; 16.9%). 11 children (3.2%) required intensive care admission for altered mental status/status epilepticus (3), sepsis (2) and ARDS (6). 119/342 (34.8%) children were treated with antibiotics because of possible or confirmed bacterial coinfection. One death was reported, concerning an 11-month-old unvaccinated infant, with underlying dystrophy, who died of sepsis.

Conclusion

Measles is not an innocent viral infection, as it is still characterized by high morbidity and complications rates. Unvaccinated or partially vaccinated populations could trigger new outbreaks, resulting in significant cost in public health. To avoid future measles outbreaks, high vaccination coverage should be achieved, as well as closing immunity gaps in the population and ensuring high-quality measles surveillance.

Clinical characteristics of COVID-19 in neonates and young infants

We report the clinical characteristics and management of fourteen neonates and very young infants with COVID-19. Although all presented with mild symptoms and did not require specific treatment, most of them had abnormal laboratory and radiological findings. Ten infants presented with neutropenia and/or monocytosis but none with lymphopenia. Transient hypertriglyceridemia and/or prolonged viral shedding were detected in 9 patients.Conclusion: Based to our experience, COVID-19 is mild in very young infants and might have distinct laboratory findings. What is Known: • SARS-CoV-2 in infants is a mild disease. • The period of transmission is approximately 2 weeks. What is New: • Very young age is not a risk factor for severe COVID-19 but could be associated with prolonged viral shedding. • Neutropenia and monocytosis are distinct characteristics of COVID-19 in very young infants.

694. Unexpected Diversity of Rotavirus Genotypes in Pediatric Population

Background

Rotavirus (RV) is the leading cause of viral gastroenteritis in children. Although RV genotypes differ geographically and temporally, five are the predominant genotypes circulating worldwide. Aim of our study was to monitor possible changes in distribution of Rotavirus genotypes circulating in Greek pediatric population during the post vaccine era.

Methods

Demographic data and fecal samples were collected from children ≤15 years old with symptoms of acute gastroenteritis who visited emergency units of Pediatric Hospitals in Greece from September 2016 to August 2019. Samples were tested for RV Group A antigen with rapid immunochromatographic assay. Positive samples were further G and P typed employing RT-PCR, semi-nested multiplex PCR and Sanger sequencing of the VP7 and VP4 genes.

Results

A total of 660 children participated in the study with median age 31±29 months. Males outnumbered females (59%). Most of them lived in urban cities (85%). RV genotyping distribution was G4P[8] (41%), G1P[8] (22%), G2P[4] (14%), G9P[8] (8%), G9P[4] (5,5%), G12P[8] (2%) and G3P[8] (1,8%). Unusual and mixed genotypes were identified in 3,2% and 2,5% of the samples respectively. During 2016-2017 and 2017-2018, G4P[8] was the predominant genotype in 67% and 51% of the annual samples. However, in 2018-2019 the most common genotypes were G9P[8] and G9P[4] (33% in total) followed by G2P[4] (27%). Interestingly, the genotype G9P[4] was not detected at all in the first two years of the study.

Conclusion

This study indicates diversity of the predominant RV genotypes in Greek children during 2016-2019. The emergence of G9 as the most common genotype as well as the significant detection of uncommon ones highlight the importance of continuous surveillance of RV genotyping during the post vaccine period.

Disclosures

All Authors: No reported disclosures

Impact of cerebrospinal fluid syndromic testing in the management of children with suspected central nervous system infection

The aim of the study was to evaluate the impact of the use of BioFire® FilmArray® meningitis/encephalitis(FA-ME) panel which enables rapid automated CSF testing for 14 common viral, bacterial, and yeast pathogens that cause CNS infections, in the management of children with suspected CNS infection. A prospective cohort study was performed on children admitted to a tertiary pediatric hospital, over a period of 1 year, with possible CNS infection and CSF pleocytosis (> 15 cells/mm³). Children were randomized 1:1, either to use FA-ME or separate molecular CSF microbiological tests according to usual pediatric practice in the hospital. Length of hospital stay, duration of antimicrobials, and total cost of hospitalization were compared between groups. A total of 142 children were included in the study (71 cases). A pathogen was detected in 37/71(52.1%) children with the use of FA-ME and in 16/71(22.5%) in the control group (P value < 0.001). In aseptic meningitis cases a virus was detected in 27/61(44.2%) and in 11/66(16.7%) controls (P value < 0.001). Median (IQR) length of stay in cases and controls with aseptic meningitis was 5(4-8) and 8(6-10) days, respectively (P value < 0. 001). The median (IQR) duration of antimicrobials in cases and controls was 4(2-5.7) and 7(5-10) days, respectively (P value < 0.001). The hospitalization cost was calculated in cases and controls 1042€ (932-1372) and 1522€ (1302-1742), respectively (P value < 0.001). The use of FA-ME was able to reduce significantly the use of antimicrobials, the hospitalization days, and the total cost comparing to the control group in children with suspected CNS infection.

1399. A Prospective Cohort Study Regarding the Impact of Biofire® FilmArray® Meningitis/Encephalitis (FA) Panel in Children with Suspected Central Nervous System Infection

Background

Rapid detection of pathogens involved in central nervous system (CNS) infections could be important for the optimal patient management and overall hospitalization cost. The aim of the study was to evaluate the possible benefits with the use of BioFire® FilmArray® meningitis/encephalitis (FA) panel in children with suspected CNS infection.

Methods

A prospective cohort study, was performed on children admitted to a tertiary pediatric hospital, over a period of 1 year (April 2018–April 2019), with possible CNS infection and cerebrospinal fluid (CSF) pleocytosis (>15 cells/mm³). For each child that FA was used for the diagnosis, an age-matched control was selected, and separate molecular CSF microbiological tests were sent according to pediatrician’s discretion. Conventional microbiological procedures were performed in all children. Length of hospital stay, duration of antimicrobials, and total cost of hospitalization were compared between groups. FA enables rapid automated cerebrospinal fluid testing for 14 common viral, bacterial and yeast pathogens that cause CNS infections. The cost was estimated according to ICD-10 diagnosis standard cost, adding additional daily hospitalization cost, FA or other molecular microbiological tests costs.

Results

A total of 142 children were included in the study (71 cases). The median age of cases and controls was 2.5 months (IQR: 1–72) and 2 months (IQR: 0.7–36) respectively (P = 0.157). A pathogen was detected in 38/71 (53.5%) children with the use of FA and in 16/71 (22.5%) in the control group (P < 0.001). In aseptic meningitis cases a virus was detected in 27/60 (45%) and in 11/64 (16.4%) controls (P < 0.001). Length of stay in cases and controls with aseptic meningitis was 5 days (IQR: 4–8) and 8 (IQR: 6–10) respectively (P < 0.001). The median duration of antimicrobials in cases was 4 days (IQR: 2–5.7) and 7 (IQR: 5–10) respectively (P < 0.001). The hospitalization cost was calculated in cases and controls 1,042 (IQR: 932–1372€) and 1,522 (IQR: 1,302–1,742€) respectively (P < 0.001).

Conclusion

The use of FA was able to reduce significantly the hospitalization days and the total cost comparing to the control group in children with suspected CNS infection.

Disclosures

All authors: No reported disclosures.

Changing Epidemiology of Invasive Candidiasis in Children during a 10-Year Period

Candida species are a common cause of invasive infection in neonates and children. The aim of our study was to evaluate the epidemiology and microbiology of invasive candidiasis (IC) in the largest tertiary Greek pediatric hospital during a 10-year period. A retrospective cohort study was performed from January 2008 to December 2017. Identification of species and antifungal susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) methodology. During the study period, 178 cases of IC were recorded. The tissue distribution included blood (87.1%), cerebrospinal (7.9%), peritoneal (3.9%) and pleural fluids (1.1%). Candida albicans and Candida parapsilosis (sensu lato) were the most frequently isolated species (47.8% and 28.7% respectively). From period 2008⁻2012 to period 2013⁻2017, a significant decrease in IC rates was detected (0.21 cases/1000 hospitalization days VS 0.11 cases/1000 hospitalization days, P = 0.040), while median minimum inhibitory concentrations (MICs) of amphotericin B were significantly increased for both C. albicans and C. parapsilosis (sl) (P = 0.037 and P = 0.004 respectively). The decrease in IC rates may reflect the increased awareness as well as the effective infection control initiatives and antifungal interventions. However, the significant increase in the MICs for amphotericin B and echinocandins such as caspofungin, raises concerns about their common use as first-line treatment. Epidemiologic monitoring is, therefore, critically important in order to evaluate and optimize therapeutic protocols for IC in pediatric populations.

Staphylococcus aureus osteoarticular infections in children: an 8-year review of molecular microbiology, antibiotic resistance and clinical characteristics

PURPOSE

To investigate the clinical, phenotypic and genotypic characteristics of Staphylococcus aureus strains causing osteoarticular infections in a large paediatric series.

METHODOLOGY

Medical records of children who were hospitalized with the diagnosis of community-associated S. aureus (CA-SA) osteomyelitis and/or septic arthritis in the two major tertiary paediatric hospitals of Athens during an 8-year period (2007-2015) were reviewed, and S. aureus isolates were analysed regarding antimicrobial resistance, detection of pathogenicity genes and genotyping using SCCmec, agr typing, PFGE and MLST.

RESULTS

During the study period, 123 children with CA-SA osteoarticular infections were identified, and methicillin-resistant S. aureus (MRSA) accounted for 44 of these (35.8 %). Children with MRSA infection had a significantly higher admission rate to the ICU (5.7  vs 0 %, P=0.04) and longer duration of hospitalization (21.6 vs 16.7 days, P=0.04). Sixty-eight isolates [42 (methicillin-sensitive S. aureus) MSSA and 26 MRSA] were available for molecular analysis. All MRSA strains were mecA-positive and most carried the SCCmec IV cassette (23/26, 88 %) and belonged to the PFGE type C (24/26, 92.3 %), agr type 3 (24/26, 92.3 %) and the MLST ST80 clone (24/26, 92.3 %). In contrast, MSSA strains showed polyclonality by PFGE and agr typing. Regarding pathogenicity genes, MRSA vs MSSA isolates showed higher detection rates of PVL (96.2 vs 4.8 %, P<0.0001) and fib (80.8 vs 50 %, P=0.02).

CONCLUSIONS

In our study a considerable number of S. aureus osteoarticular infections were due to CA-MRSA isolates, most of which belonged to the ST80 clone and had a higher incidence of specific virulence factors, entailing higher ICU admission rates and a longer duration of hospitalization.

Molecular epidemiology of Bordetella pertussis in Greece, 2010-2015

Purpose

To determine the predominant strains of Bordetella pertussis in Greece during 2010–2015.

Methodology

Infants and children (n=1150) (15 days to 14 years) of Greek, Roma and immigrant origin with different vaccination statuses were hospitalized in Athens, Greece with suspected pertussis infection. IS481/IS1001 real-time PCR confirmed Bordetella spp./B. pertussis infection in 300 samples. A subset of samples (n=153) were analysed by multi-locus variable number tandem repeat analysis (MLVA) and (n=25) by sequence-based typing of the toxin promotor region (ptxP) on DNA extracted from clinical specimens.

Results/Key findings

A complete MLVA profile was determined in 66 out of 153 samples; the B. pertussis MLVA type 27 (n=55) was the dominant genotype and all tested samples (n=25) expressed the ptxP3 genotype. The vaccine coverage in the Greek population was 90 %; however, the study population expressed complete coverage in 2 out of 264 infants (0–11 months) and in 20 out of 36 children (1–14 years). Roma and immigrant minorities represent 7 % of the Greek population, but make up 50 % of the study population, indicating a low vaccine coverage among these groups.

Conclusions

The B. pertussis MT27 and ptxP3 genotype is dominant in Greek, Roma and immigrant infants and children hospitalized in Greece. Thus, the predominant MLVA genotype in Greece is similar to other countries using acellular vaccines.

Early-Life Pseudomonas aeruginosa Infection in Cystic Fibrosis and Lung Disease Progression

Lung disease in cystic fibrosis (CF) starts early, with studies identifying abnormalities on chest computed tomography (CT) scan even in infancy. In this retrospective study, abnormal chest CT was the main outcome; body mass index (BMI) z score and forced expiratory volume percent predicted (FEV₁%) predicted at age 6 to 7 years were secondary outcomes. Pseudomonas aeruginosa infection prior to 12 months of age was the main explanatory variable. There was no association between early P aeruginosa infection and abnormal CT after adjustment for CFTR (cystic fibrosis transmembrane conductance regulator) functional mutation class, gender, and other pathogens (odds ratio = 0.30; 95% confidence interval = 0.07-1.35; P = .11). No significant associations were demonstrated for BMI z score and FEV₁% predicted. Children with class I-III CFTR mutations had increased risk of abnormal CT findings (odds ratio = 11.67; 95% confidence interval = 1.11-115.06; P = .035) and lower FEV₁% predicted (P = .04). In the current era, early-life P aeruginosa infection in CF might not influence the severity of lung disease in school age as much as previously. Larger studies are needed to confirm this finding.

Detection of bacterial pathogens in synovial and pleural fluid with the FilmArray Blood Culture Identification System

We report the use of FilmArray Blood Culture Identification (BCID) multiplex PCR system for pathogen detection from a child with septic arthritis that Streptococcus pyogenes was identified directly from synovial fluid and a child with complicated pneumonia with pleural effusion that Streptococcus pneumoniae was identified from pleural fluid.

Management of coronary artery aneurysms using abciximab in children with Kawasaki disease

INTRODUCTION

There are limited data regarding the possible benefits of abciximab in children with Kawasaki disease (KD), who developed serious cardiac abnormalities non-responsive to standard treatment.

MATERIALS AND METHODS

We retrospectively identified children with KD who were treated with abciximab from 2007 to 2015. Data regarding clinical course, treatment, echocardiographic data and follow-up at 1 and 6months were retrieved.

RESULTS

During the study period, fifteen children were identified who were diagnosed with KD and were given abciximab. The median age at onset of symptoms was 11months (range: 2months-6years). The median day of disease at admission was 10days (range: 4-26days) and the median day of administration of abciximab was 17days (range: 9-40). Twelve children were diagnosed with complete and three with incomplete KD. Aneurysms were found in 8 children: 2 had ectatic coronary arteries and 5 presented with both ectasia and aneurysms. At 1month follow-up, echocardiographic findings showed regression in the size of aneurysms in 11 children, resolution of the aneurysms or ectasia of coronary arteries in 3 children, while one child who could not take aspirin because of G6PD deficiency died. After 6months of follow-up, echocardiographic findings showed resolution of coronary abnormalities in 12 (80%) children, whereas 2 children (13.3%) presented with significant regression of aneurysms.

CONCLUSIONS

Abciximab may have an important role in the management of severe cardiac complications of KD, although prospective randomized controlled studies are needed to fully evaluate its role.

Genital HPV in Children and Adolescents: Does Sexual Activity Make a Difference?

STUDY OBJECTIVE

To compare the prevalence of human papillomavirus (HPV) genital infection among prepubertal children, sexually active and not sexually active adolescents, and assess potential risk factors for transmission.

DESIGN

Prospective study.

SETTING

Outpatient adolescent health clinic.

PARTICIPANTS

Ninety-five girls aged 2-21 years; 38 sexually active adolescents (group A), 28 not sexually active adolescents (group B), and 29 prepubertal children (group C).

INTERVENTIONS

Participants' vaginal or cervical specimens were tested for HPV with the CLART HPV 2 assay (Clinical Array Technology, Genomica, Madrid, Spain) and for cytological abnormalities with liquid-based cytology.

MAIN OUTCOME MEASURES

Differences in prevalence of low- and high-risk HPV infections among the 3 groups.

RESULTS

Genital HPV was detected in 37.9% (36/95) of all participants; 47.4% (18/38) of group A, 28.6% (8/28) of group B, and 34.5% (10/29)of group C (P = .27). Multiple HPV infection was detected in 26.3% (10/38), 10.7% (3/28), and 13.8% (4/29) of groups A, B, and C, respectively (P = .21). High-risk genotypes were detected in 47.4% (18/38), 28.6% (8/28), and 24.1% (7/29) of groups A, B, and C, respectively (P = .10). Main high-risk genotypes were HPV 16 (27%, 10/37), HPV 31 (21.6%, 8/37 ), HPV 35 (13.5%, 5/37), HPV 53 (13.5%, 5/37), and low-risk HPV 6 (18.9%, 7/37). Sexual activity was associated with increased risk for genital high-risk HPV infection (odds ratio = 3.41; 95% confidence interval, 1.19-9.78); specifically with HPV 33 and HPV 51. Forty percent of sexually active adolescents with normal cervical cytology were infected with high-risk HPV types. Family history of skin HPV was positively associated with genital HPV in the sexually active group (odds ratio = 2.01; 95% confidence interval, 1.17-3.46).

CONCLUSION

Timeline and target population for HPV vaccination might need to be reappraised, in view of significant nonsexual transmission of genital HPV so early in childhood.

Molecular analysis of Streptococcus pyogenes macrolide resistance of paediatric isolates during a 7 year period (2007-13)

OBJECTIVES

The molecular characterization of paediatric group A Streptococcus (GAS) isolates regarding macrolide resistance and relevant emm types in Athens, Greece.

METHODS

Pharyngeal and non-pharyngeal GAS isolates were collected during a 7 year period (2007-13) and examined for antibiotic susceptibility, macrolide resistance genes [mef(A), erm(A) and erm(B)] and relevant emm types.

RESULTS

Overall, 20.4% (270/1324) of GAS isolates were resistant to macrolides. The macrolide resistance rate varied during the study period with a maximum rate observed in 2008 (29.57%) and a minimum rate observed in 2013 (10.95%) (P value for trend = 0.007). During the same period, consumption of macrolides was gradually reduced by 56.6%. No difference was observed in macrolide resistance between pharyngeal and non-pharyngeal isolates (P = 0.7). Among macrolide-resistant isolates, mef(A) was detected in 87 (32.2%), erm(A) in 136 (50.4%), erm(B) in 44 (16.3%) and both mef(A) and erm(A) in 3 (1.1%) isolates. The most prevalent emm types among macrolide-resistant isolates were emm77 (31.5%), emm4 (18.1%) and emm12 (10.7%). Ten emm types (77, 4, 12, 28, 1, 22, 11, 2, 44 and 89) accounted for 90.3% of macrolide-resistant isolates. emm types 4, 22, 44 and 77 were more prevalent in macrolide-resistant compared with macrolide-susceptible isolates, whereas emm types 1, 3, 5, 6, 75 and 89 were more prevalent in macrolide-susceptible compared with macrolide-resistant isolates.

CONCLUSIONS

GAS macrolide resistance remained significant in our area during the study period. A substantial decline in the resistance rate was observed in the last year of the study, which may be related to reduced consumption of macrolides.