Children and COVID-19: Microbiological and immunological insights

Non-fatal outcomes of COVID-19 disease in pediatric organ transplantation associates with down-regulation of senescence pathways

This is a cross-sectional study examining kinetics and durability of immune response in children with solid organ transplants (SOTs) who had COVID-19 disease between November 2020 through June 2022, who were followed for 60-days at a single transplant center. Blood was collected between 1-14 (acute infection), and 15-60 days of a positive PCR (convalescence). SOT children with peripheral blood mononuclear cells (PBMC) cryopreserved before 2019 were non-infected controls (ctrls). PBMCs stimulated with 15-mer peptides from spike protein and anti-CD49d/anti-CD28. Testing done included mass cytometry, mi-RNA sequencing with confirmatory qPCR. 38 children formed the study cohort, 10 in the acute phase and 8 in the convalescence phase. 20 subjects were non-infected controls. Two subjects had severe disease. Subjects in the acute and convalescent phases were different subjects. The median age and tacrolimus level at blood draw was not significantly different. There was no death, and no subject was lost to follow-up. During acute infection CD57 expression was low in NKT, Th17 effector memory, memory Treg, CD4-CD8-, and γδT cells (p = 0.01, p = 0.04, p = 0.03, p = 0.03, p = 0.004 respectively). The frequencies of NK and Th2 effector memory cells increased (p = 0.01, p = 0.02) during acute infection. Non-switched memory B and CD8 central memory cell frequencies were decreased during acute infection (p = 0.02; p = 0.02), but the decrease in CD8 central memory cells did not persist. CD4-CD8- and CD14 monocyte frequencies increased during recovery (p = 0.03; p = 0.007). Our observations suggest down regulation of CD57 with absence of NK cell contraction protect against death from COVID-19 disease in children with SOTs.

Tissue expression of the SARS-CoV-2 cell receptor gene ACE2 in children

Coronavirus disease 2019 (COVID-19) has become a significant global public health problem. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which causes the disease, utilizes angiotensin-converting enzyme II (ACE2) as a major functional receptor to enter host cells. No study has systematically assessed ACE2 expression in multiple tissues in children. This study investigated ACE2 expression and ACE2 protein's histological distribution in various organs in paediatric patients (the small intestine, thymus, heart and lungs). Our study revealed that ACE2 was highly expressed in enterocytes of the small intestine and widely expressed in the myocardium of heart tissues. The most notable finding was the positive staining of ACE2 in the Hassall's corpuscles epithelial cells. Negligible ACE2 expression in the lung tissues may contribute to a lower risk of infection and fewer symptoms of pneumonia in children than in adults with COVID-19 infection. These findings provide initial evidence for understanding SARS-CoV-2 pathogenesis and prevention strategies in paediatric clinical practice, which should be applicable for all children worldwide.

PANDAS/PANS in the COVID-19 Age: Autoimmunity and Epstein-Barr Virus Reactivation as Trigger Agents?

COVID-19 impacted the entire world's population, frequently resulting in long-lasting neuropsychiatric complications. Furthermore, social distancing, lockdowns and fear for one's personal health worsen individual psychological wellbeing, especially in children and adolescents. Herein, we discuss the results of studies that specifically reported data about the impact of the COVID-19 pandemic or infection on children with Pediatric Acute-Onset Neuropsychiatric Disorders (PANS). Furthermore, we present the cases of five adolescents with PANS whose symptomatology increased following SARS-CoV-2 infection. What emerged from this study was that COVID-19 resulted in the exacerbation of obsessions, tics, anxiety and mood symptoms and decreased wellbeing. Moreover, new symptoms, as well as new PANS cases, are reported to have arisen after COVID-19 infection. Here, we hypothesize that the pathogenic mechanisms of silent viruses, such as the Epstein-Barr virus, are related to neuroinflammation, immune responses and reactivation, with additional roles played by social-isolation-related inflammatory processes. The discussion of PANS, which represents a model of immune-mediated neuropsychiatric manifestations, is particularly relevant, with the aim of uncovering the mechanisms that lead to neuropsychiatric Post-Acute COVID-19 Syndrome (PACS). Prospects for future studies and treatment implications are discussed.

The Gut Microbiome of Children during the COVID-19 Pandemic

The gut microbiome has been shown to play a critical role in maintaining a healthy state. Dysbiosis of the gut microbiome is involved in modulating disease severity and potentially contributes to long-term outcomes in adults with COVID-19. Due to children having a significantly lower risk of severe illness and limited sample availability, much less is known about the role of the gut microbiome in children with COVID-19. It is well recognized that the developing gut microbiome of children differs from that of adults, but it is unclear if this difference contributes to the different clinical presentations and complications. In this review, we discuss the current knowledge of the gut microbiome in children with COVID-19, with gut microbiome dysbiosis being found in pediatric COVID-19 but specific taxa change often differing from those described in adults. Additionally, we discuss possible mechanisms of how the gut microbiome may mediate the presentation and complications of COVID-19 in children and the potential role for microbial therapeutics.

SARS-CoV-2 specific antibody trajectories in mothers and infants over two months following maternal infection

Infants exposed to caregivers infected with SARS-CoV-2 may have heightened infection risks relative to older children due to their more intensive care and feeding needs. However, there has been limited research on COVID-19 outcomes in exposed infants beyond the neonatal period. Between June 2020 - March 2021, we conducted interviews and collected capillary dried blood spots from 46 SARS-CoV-2 infected mothers and their infants (aged 1-36 months) for up to two months following maternal infection onset (COVID+ group, 87% breastfeeding). Comparative data were also collected from 26 breastfeeding mothers with no known SARS-CoV-2 infection or exposures (breastfeeding control group), and 11 mothers who tested SARS-CoV-2 negative after experiencing symptoms or close contact exposure (COVID- group, 73% breastfeeding). Dried blood spots were assayed for anti-SARS-CoV-2 S-RBD IgG and IgA positivity and anti-SARS-CoV-2 S1 + S2 IgG concentrations. Within the COVID+ group, the mean probability of seropositivity among infant samples was lower than that of corresponding maternal samples (0.54 and 0.87, respectively, for IgG; 0.33 and 0.85, respectively, for IgA), with likelihood of infant infection positively associated with the number of maternal symptoms and other household infections reported. COVID+ mothers reported a lower incidence of COVID-19 symptoms among their infants as compared to themselves and other household adults, and infants had similar PCR positivity rates as other household children. No samples returned by COVID- mothers or their infants tested antibody positive. Among the breastfeeding control group, 44% of mothers but none of their infants tested antibody positive in at least one sample. Results support previous research demonstrating minimal risks to infants following maternal COVID-19 infection, including for breastfeeding infants.

SARS-CoV-2 Infection in Pediatric Solid Organ Transplant Recipients: A Single Center Observation

OBJECTIVES

This is a descriptive study to characterize rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pediatric solid organ transplant (SOT) recipients during the early days of the pandemic. We hypothesized that asymptomatic infection may represent a large proportion of SARS-CoV-2 infection in pediatric SOT recipients.

METHODS

We queried Organ Transplant Tracking Record (OTTR) for all pediatric SOT recipients followed at our center and reviewed medical records to identify patients tested for SARS-CoV-2 between March 15, 2020 and June 30, 2021. Patients were tested by polymerase chain reaction (PCR): prior to planned procedures or because of symptoms; OR: tested by measurement of IgG to spike protein with their routine labs q 2-monthly. A positive PCR was called acute infection. A positive IgG with negative PCR was called convalescence. For immunologic studies, blood was obtained when the PCR or IgG was positive. Statistical comparisons were made between (1) acute infection versus convalescence; (2) acute infection versus SOT recipients without infection (called healthy controls); (3) liver transplant (LT) versus small bowel (SB)/multivisceral transplant (MVT); (4) positive versus negative test result.

RESULTS

Of 257 LT recipients, 99 were tested: 6 were PCR positive, 13 were antibody positive. Of 150 SB/MVT recipients, 55 were tested: 4 were PCR positive, 6 were antibody positive. Of 8 simultaneous liver, kidney transplant recipients, 3 were tested: 1 was PCR positive. Symptoms when present were mostly mild. Patients with a positive test result were younger (6.3 vs 10.0 years; P = 0.017). We observed a rapid decline in viral load within 96 hours without a change in immunosuppression. Antibody lasted >8 months beyond the time it was monitored. Acute infection was associated with increased CD4 and CD8 T EM cell frequency ( P = 0.04, P = 0.03, respectively), decreased interferon (IFN)-γ production from T-cells (2.8% vs 11.3%; P = 0.006), and decreased CD8 TEMRA frequency (4.56% vs 11.70%; P = 0.006).

CONCLUSIONS

Early in the pandemic, COVID-19 disease was mostly mild in pediatric SOT recipients with no rejection, patient death, or graft loss observed.

Gut microbiota and COVID-19: An intriguing pediatric perspective

Gastrointestinal (GI) involvement has been reported in approximately 50% of patients with coronavirus disease 2019 (COVID-19), which is due to the pathogenic role of inflammation and the intestinal function of the angiotensin-converting enzyme 2 and its receptor. Accumulating adult data has pointed out that gut dysbiosis might occur in these patients with a potential impact on the severity of the disease, however the role of gut microbiota in susceptibility and severity of COVID-19 disease in children is still poorly known. During the last decades, the crosstalk between gut and lung has been largely recognized resulting in the concept of "gut-lung axis" as a central player in modulating the development of several diseases. Both organs are involved in the common mucosal immune system (including bronchus-associated and gut-associated lymphoid tissues) and their homeostasis is crucial for human health. In this framework, it has been found that the role of GI dysbiosis is affecting the homeostasis of the gut-liver axis. Of note, a gut microbiome imbalance has been linked to COVID-19 severity in adult subjects, but it remains to be clarified. Based on the increased risk of inflammatory diseases in children with COVID-19, the potential correlation between gut microbiota dysfunction and COVID-19 needs to be studied in this population. We aimed to summarize the most recent evidence on this striking aspect of COVID-19 in childhood.

Antioxidant status in children and adolescents with COVID-19

Background. The COVID-19 pandemic has raised the importance of this problem to the first stage and has affected healthcare system around the world. Despite the more favorable COVID-19 course, the child population should be at focus of special attention, due to the active participation in its distribution. The course of COVID-19 includes a cascade of pathological processes accompanied by the generation of reactive oxygen species, which can have extremely negative consequences for the developing organism. The research of these processes in children is vital and will improve the effectiveness of preventive and therapeutic measures. The aim: to analyze changes in enzymatic and non-enzymatic links in the antioxidant defense in children and adolescents with diagnosed COVID-19 infection.Materials and methods. 17 children and adolescents (average age – 12.35 ± 4.01 years) were examined, including 8 boys (47 %) and 9 girls (53 %) with COVID-19 infection. The control group of children and adolescents (practically healthy) according to the «copy-pair» principle was selected. We used spectrophotometric methods.Results. In the group of children and adolescents with diagnosed COVID-19 infection, there were lower levels of total antioxidant activity (p < 0.0001), superoxide dismutase activity (p < 0.0001), content of reduced glutathione (p = 0.048) and retinol (p = 0.015), increase in glutathione reductase activity (p = 0.015) relative to the control.Conclusion. The obtained data indicate the insufficiency of antioxidant system components number in children and adolescents with diagnosed COVID-19 infection and indicate the advisability of antioxidant therapy using to stabilize these indicators.

Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 in Households with Children, Southwest Germany, May-August 2020

Resolving the role of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in households with members from different generations is crucial for containing the current pandemic. We conducted a large-scale, multicenter, cross-sectional seroepidemiologic household transmission study in southwest Germany during May 11-August 1, 2020. We included 1,625 study participants from 405 households that each had ≥1 child and 1 reverse transcription PCR-confirmed SARS-CoV-2-infected index case-patient. The overall secondary attack rate was 31.6% and was significantly higher in exposed adults (37.5%) than in children (24.6%-29.2%; p = <0.015); the rate was also significantly higher when the index case-patient was >60 years of age (72.9%; p = 0.039). Other risk factors for infectiousness of the index case-patient were SARS-CoV-2-seropositivity (odds ratio [OR] 27.8, 95% CI 8.26-93.5), fever (OR 1.93, 95% CI 1.14-3.31), and cough (OR 2.07, 95% CI 1.21-3.53). Secondary infections in household contacts generate a substantial disease burden.

Clinical features and follow-up of pediatric patients hospitalized for COVID-19

OBJECTIVE

This report summarizes the clinical features and 1-month follow-up observations for pediatric patients who were hospitalized with coronavirus disease 2019 (COVID-19) in Wuhan Women and Children's Hospital.

METHODS

The 1-month follow-up data included clinical manifestations and results from serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG and IgM tests, reverse-transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2, lung computed tomography (CT) scans, and laboratory tests.

RESULTS

Between January 20 and March 15, 2020, 127 patients aged 0-15 years were hospitalized for COVID-19 treatment, including 3 severe cases and 124 mild or moderate cases. The main therapies included inhalation of aerosolized interferon-α (122/127) and additional antiviral drugs (28/127). Among the 81 patients who had pneumonia at admission, 35 with right lobe pneumonia had the longest hospital stay (mean 14.5 ± 7 days); 17 with left lobe pneumonia had the highest creatine kinase (154 ± 106 U/L) and creatine kinase myocardial band  (CK-MB, 43 ± 48 U/L) levels; and 29 with bilateral pneumonia had the highest white blood cell counts (8.3 ± 4 × 109 /L). Among the 46 patients who were successfully followed up 1 month after discharge, two notable findings were right lobe pneumonia in 22% (95% confidence interval [CI]: 11%-37%) of patients and persistently elevated serum creatine kinase and CK-MB levels. The median duration of elevated CK-MB was 45 days. The mean concentrations of serum SARS-CoV-2 IgG and IgM in 41 patients were 8.0 ± 7.5 and 98 ± 40 ng/ml, respectively. At follow-up, four patients retested positive for SARS-CoV-2.

CONCLUSIONS

The involvement of different lung lobes in patients with COVID-19 was associated with variations in the persistence of pneumonia and elevation of CK-MB levels and body temperature.

Pediatric Coronavirus Disease 2019: Why Is It Less Severe and Frequent in Children than Adults?

There is no abstract.

A Systematic Analysis on COVID-19 Patients in Inner Mongolia Based on Dynamic Monitoring

COVID-19 has spread globally with over 90,000,000 incidences and 1,930,000 deaths by Jan 11, 2021, which poses a big threat to public health. It is urgent to distinguish COVID-19 from common pneumonia. In this study, we reported multiple clinical feature analyses on COVID-19 in Inner Mongolia for the first time. We dynamically monitored multiple clinical features of all 75 confirmed COVID-19 patients, 219 pneumonia patients, and 68 matched healthy people in Inner Mongolia. Then, we studied the association between COVID-19 and clinical characteristics, based on which to construct a novel logistic regression model for predicting COVID-19. As a result, among the tested clinical characteristics, WBC, hemoglobin, C-reactive protein (CRP), ALT, and Cr were significantly different between COVID-19 patients and patients in other groups. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was 0.869 for the logistic regression model using multiple factors associated with COVID-19. Furthermore, the CRP reaction showed five different time-series patterns with one-peak and double-peak modes. In conclusion, our study identified a few clinical characteristics significantly different between COVID-19 patients and others in Inner Mongolia. The features can be used to establish a reliable logistic regression model for predicting COVID-19.

The Relationship between COVID-19 and Innate Immunity in Children: A Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for the pandemic viral pneumonia that was first identified in Wuhan, China, in December 2019, and has since rapidly spread around the world. The number of COVID-19 cases recorded in pediatric age is around 1% of the total. The immunological mechanisms that lead to a lower susceptibility or severity of pediatric patients are not entirely clear. At the same time, the immune dysregulation found in those children who developed the multisystem inflammatory syndrome (MIC-S) is not yet fully understood. The aim of this review is to analyze the possible influence of children's innate immune systems, considering the risk of contracting the virus, spreading it, and developing symptomatic disease or complications related to infection.

Update on SARS-CoV-2 infection in children

Despite the worldwide spread of SARS-CoV-2 infection (COVID-19), knowledge of the different clinical presentations, ways of transmission, severity and prognosis in children and adolescents is limited. An increasing number of reports describe some of these characteristics in this age range. A non-systematic review was undertaken using MEDLINE (PubMed), LILACS (VHL), Scopus, Web of Science, Cochrane and CAPES Portal databases from 1 January until 30 September 2020 [103] with the search terms SARS-CoV-2, COVID-19, child, children, youth, adolescent and newborn to identify the more recent clinical aspects of SARS-CoV-2 infection in children. In general, SARS-CoV-2 infection in children tends to be asymptomatic or to have mild or moderate signs, and most young ones are infected by family members. Recent reports offer new insights into the disease. Current evidence on SARS-CoV-2 infection in children and adolescents is presented, especially concerning the clinical presentation, imaging and uncommon severe forms of the disease, particularly the COVID-19-associated multisystem inflammatory syndrome. The impact of COVID-19 infection in the perinatal period is described in detail. Knowledge of the various clinical presentations of SARS-CoV-2 in children and adolescents allows the paediatrician to diagnose earlier, monitor warnings signs, implement treatment and, especially, establish preventive measures.Abbreviations : ACE-2, angiotensin-converting enzyme 2; ARDS, acute respiratory distress syndrome; ARF, acute rheumatic fever; CAA, coronary artery aneurysms; CK-MB, creatine kinase-MB; COVID-19, coronavirus disease-2019; HLA, specific human leucocyte antigen; IPC, infection prevention and control; IVIG, intravenous immunoglobulin; KD, Kawasaki disease; MIS-C, COVID-19-associated multisystem inflammatory syndrome; RNA, ribonucleic acid; RT-PCR, reserve transcription-polymerase chain reaction; SARS-CoV-2, severe acute respiratory syndrome coronavirus-2; TCT, thoracic computed tomography; TSS, toxic shock syndrome; WHO, World Health Organization.

COVID-19 in Children: A Review and Parallels to Other Hyperinflammatory Syndromes

During the COVID-19 pandemic, children have had markedly different clinical presentations and outcomes compared to adults. In the acute phase of infection, younger children are relatively spared the severe consequences reported in adults. Yet, they are uniquely susceptible to the newly described Multisystem Inflammatory Syndrome in Children (MIS-C). This may result from the developmental "immunodeficiency" resulting from a Th2 polarization that starts in utero and is maintained for most of the first decade of life. MIS-C may be due to IgA complexes in a Th2 environment or a Th1-like response to COVID-19 antigens that developed slowly. Alternatively, MIS-C may occur in vulnerable hosts with genetic susceptibilities in other immune and non-immune pathways. Herein, we present a brief overview of the host immune response, virologic and genetic factors, and comparable inflammatory syndromes that may explain the pathophysiology leading to drastic differences in clinical presentation and outcomes of COVID-19 between children and adults.