The potential threat of multisystem inflammatory syndrome in children during the COVID-19 pandemic

Specialty follow -up care after hospital discharge of patients with multisystem inflammatory syndrome in children associated with COVID-19 from a rural tertiary-care hospital

BACKGROUND

The clinical features of Multisystem Inflammatory Syndrome in Children (MIS-C) have been well documented, but there is limited data regarding the short term and longitudinal outcomes of children living in rural areas. We report the demographic and clinical features, as well as the multi-specialty follow-up of patients with MIS-C served by a large tertiary care rural health system.

METHODS

Patients that met the Centers for Disease Control (CDC) case definition of MIS-C admitted between March 1, 2020, and March 31, 2021, were included in this case series. Manual chart review was used to report demographic characteristics, clinical, laboratory and radiologic features during acute hospitalization and multispecialty follow-up, and adherence to follow-up 6-10 weeks after hospital discharge.

RESULTS

Twenty-one patients with MIS-C were admitted at our center during the review period. Ninety percent of the cohort required intensive care during hospitalization. Of 19 patients with measured ejection fractions, 52 % had some degree of left ventricular dysfunction on admission; nine patients had electrocardiogram changes on admission. The majority of patients had elevated inflammatory markers during hospitalization. Most patients had resolution of symptoms, improvement in inflammatory markers, and normal cardiac function at the time of discharge. Follow-up with pediatric cardiology, hematology-oncology and infectious disease was indicated for most patients at discharge. Of these, 100 % of patients kept initial follow-up appointments with pediatric cardiology and infectious disease, while 94 % kept initial follow-up appointments with pediatric hematology-oncology.

CONCLUSION

Though most patients were critically ill during hospitalization, the majority had resolution of cardiac abnormalities and inflammatory markers at discharge and timely follow-up with multiple subspecialists after admission with MIS-C.

Cerebral venous sinus thrombosis related to SARS-CoV-2 infection in a pediatric patient: A case report

Coronavirus disease 2019 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); it has recently been associated with several hematologic disorders. A 4-year-old boy who had SARS-CoV-2 10 months prior was admitted to the emergency department of our hospital with seizures. His SARS-CoV-2 IgG II level was 885.7 AU/mL. Neuroimaging with cranial computed tomography after admission showed abnormal images of the venous sinus, but this was not sufficient to diagnose cerebral venous sinus thrombosis. Therefore, magnetic resonance imaging and digital subtraction angiography were conducted, which confirmed the diagnosis. He was treated with thrombectomy and anticoagulation drugs, and the clinical outcomes were satisfactory. Because our patient had a medical history of SARS-CoV-2 and exhibited no other risk factors, we present this case as evidence of a potential association between cerebral venous sinus thrombosis and SARS-CoV-2.

Pediatric multisystem inflammatory syndrome associated with COVID-19: Insights in pathogenesis and clinical management

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been a major challenge to be faced in recent years. While adults suffered the highest morbidity and mortality rates of coronavirus disease 2019, children were thought to be exclusively asymptomatic or to present with mild conditions. However, around April 2020, there was an outbreak of a new clinical syndrome related to SARS-CoV-2 in children - multisystemic inflammatory syndrome in children (MIS-C) - which comprises a severe and uncon-trolled hyperinflammatory response with multiorgan involvement. The Centers for Disease Control and Prevention considers a suspected case of MIS-C an individual aged < 21 years presenting with fever, high inflammatory markers levels, and evidence of clinically severe illness, with multisystem (> 2) organ involvement, no alternative plausible diagnoses, and positive for recent SARS-CoV-2 infection. Despite its severity, there are no definitive disease management guidelines for this condition. Conversely, the complex pathogenesis of MIS-C is still not completely understood, although it seems to rely upon immune dysregulation. Hence, in this study, we aim to bring together current evidence regarding the pathogenic mechanisms of MIS-C, clinical picture and management, in order to provide insights for clinical practice and implications for future research directions.

COVID-19 coronavirus infection in children: Clinical presentation, diagnosis, vaccination, and treatment

In late 2019, a new subtype of coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (COVID-19 SARS-CoV-2) rapidly spread around the world, causing a global pandemic. Initially, the proportion of confirmed cases among children was relatively small, and it was believed that children were rarely infected. Subsequent observations have shown that in children and adolescents, the infection is either asymptomatic or paucisymptomatic, and therefore the true incidence is underestimated due to the lack of testing. The article systematizes the results of studies on the prevalence, diagnosis, clinical features, vaccination, and treatment of children with a new coronavirus infection COVID-19 SARS-CoV-2. The SARS-CoV-2 positivity rate throughout the peak of the pandemic in children was low compared to adults. Children are not only less likely to become infected with the virus, but they also endure the infection more easily than adults. The mortality rate in children with COVID-19 was <0.5%. In most children, infection is either asymptomatic or paucisymptomatic. Vaccination of children and adolescents is recommended mainly to achieve herd immunity in all age groups. However, there are no convincing data on the duration of the immune response, the level of the required protective antibody titer, as well as on the long-term side effects of vaccination due to the insufficient follow-up period and the uncertainty of the immune response criteria. As information is accumulated on the viral load of children and adolescents, their role in the transmission of the virus, diagnostic approaches in this age group are optimized. The effectiveness of the treatment was tested on patients admitted to the hospital, and recommendations for treatment were developed. Currently, global research efforts are focused on the protection of particularly vulnerable children, the prospects for total childhood vaccination, its effectiveness and safety.

Critical role of diagnostic SARS-CoV-2 T cell assays for immunodeficient patients

After almost 3 years of intense study, the immunological basis of COVID-19 is better understood. Patients who suffer severe disease have a chaotic, destructive immune response. Many patients with severe COVID-19 produce high titres of non-neutralising antibodies, which are unable to sterilise the infection. In contrast, there is increasing evidence that a rapid, balanced cellular immune response is required to eliminate the virus and mitigate disease severity. In the longer term, memory T cell responses, following infection or vaccination, play a critical role in protection against SARS-CoV-2.Given the pivotal role of cellular immunity in the response to COVID-19, diagnostic T cell assays for SARS-CoV-2 may be of particular value for immunodeficient patients. A diagnostic SARS-CoV-2 T cell assay would be of utility for immunocompromised patients who are unable to produce antibodies or have passively acquired antibodies from subcutaneous or intravenous immunoglobulin (SCIG/IVIG) replacement. In many antibody-deficient patients, cellular responses are preserved. SARS-CoV-2 T cell assays may identify breakthrough infections if reverse transcriptase quantitative PCR (RT-qPCR) or rapid antigen tests (RATs) are not undertaken during the window of viral shedding. In addition to utility in patients with immunodeficiency, memory T cell responses could also identify chronically symptomatic patients with long COVID-19 who were infected early in the pandemic. These individuals may have been infected before the availability of reliable RT-qPCR and RAT tests and their antibodies may have waned. T cell responses to SARS-CoV-2 have greater durability than antibodies and can also distinguish patients with infection from vaccinated individuals.

Allergic diseases and immunodeficiencies in children, lessons learnt from COVID-19 pandemic by 2022: A statement from the EAACI-section on pediatrics

By the April 12, 2022, the COVID-19 pandemic had resulted in over half a billion people being infected worldwide. There have been 6.1 million deaths directly due to the infection, but the pandemic has had many more short- and long-term pervasive effects on the physical and mental health of the population. Allergic diseases are among the most prevalent noncommunicable chronic diseases in the pediatric population, and health-care professionals and researchers were seeking answers since the beginning of pandemic. Children are at lower risk of developing severe COVID-19 or dying from infection. Allergic diseases are not associated with a higher COVID-19 severity and mortality, apart from severe/poorly controlled asthma. The pandemic disrupted routine health care, but many mitigation strategies, including but not limited to telemedicine, were successfully implemented to continue delivery of high-standard care. Although children faced a multitude of pandemic-related issues, allergic conditions were effectively treated remotely while reduction in air pollution and lack of contact with outdoor allergens resulted in improvement, particularly respiratory allergies. There is no evidence to recommend substantial changes to usual management modalities of allergic conditions in children, including allergen immunotherapy and use of biologicals. Allergic children are not at greater risk of multisystem inflammatory syndrome development, but some associations with Long COVID were reported, although the data are limited, and further research is needed. This statement of the EAACI Section on Pediatrics provides recommendations based on the lessons learnt from the pandemic, as available evidence.

SARS-CoV-2 Omicron: Light at the End of the Long Pandemic Tunnel or Another False Dawn for Immunodeficient Patients?

COVID-19 has had a disastrous impact on the world. Apart from at least 6 million deaths, countless COVID-19 survivors are suffering long-term physical and psychiatric morbidity. Hundreds of millions have been plunged into poverty caused by economic misery, particularly in developing nations. Early in the pandemic, it became apparent certain groups of individuals such as the elderly and those with comorbidities were more likely to suffer severe disease. In addition, patients with some forms of immunodeficiency, including those with T-cell and innate immune defects, were at risk of poor outcomes. Patients with immunodeficiencies are also disadvantaged as they may not respond optimally to COVID-19 vaccines and often have pre-existing lung damage. SARS-CoV-2 Omicron (B.1.529) and its subvariants (BA.1, BA.2, etc) have emerged recently and are dominating COVID-19 infections globally. Omicron is associated with a reduced risk of hospitalization and appears to have a lower case fatality rate compared with previous SARS-CoV-2 variants. Omicron has offered hope the pandemic may finally be coming to an end, particularly for vaccinated, healthy individuals. The situation is less clear for individuals with vulnerabilities, particularly immunodeficient patients. This perspective offers insight into potential implications of the SARS-CoV-2 Omicron variant for patients with immunodeficiencies.

Severe COVID-19 is a T cell immune dysregulatory disorder triggered by SARS-CoV-2

INTRODUCTION

COVID-19 has had a calamitous impact on the global community. Apart from at least 6M deaths, hundreds of millions have been infected and a much greater number have been plunged into poverty. Vaccines have been effective but financial and logistical challenges have hampered their rapid global deployment. Vaccine disparities have allowed the emergence of new SARS-CoV-2 variants including delta and omicron, perpetuating the pandemic.

AREAS COVERED

The immunological response to SARS-CoV-2 has been the subject of intense study and is now better understood. Many of the clinical manifestations of severe disease are a consequence of immune dysregulation triggered by the virus. This may explain the lack of efficacy of antiviral treatments such as convalescent plasma infusions, given later in the disease.

EXPERT OPINION

T cells play a crucial role in both the outcome of COVID-19 as well as the protective response to vaccines. Vaccines do not prevent infection but reduce the risk of a chaotic and destructive cellular immune response to the virus. Severe COVID-19 should be considered a virus-induced secondary immune dysregulatory disorder of cellular immunity, with broad host susceptibility. This perspective of COVID-19 will lead to better diagnostic tests, vaccines and therapeutic strategies in the future.

Severe Multi-inflammatory Syndrome in Children Temporally Related to COVID 19-Clinical Course, Laboratory Profile and Outcomes from a North Indian PICU

Objective: We describe the trajectory of clinical course, laboratory markers and outcomes in children with severe multi-inflammatory syndrome temporally related to COVID-19 (MIS-C) admitted to our pediatric intensive care unit (PICU). Methods: This was a prospective case series of children admitted to PICU between May 1, 2020 and January 31, 2021, fulfilling the case definition of MIS-C published by World Health Organization (WHO) or Centers for Disease Control and Prevention (CDC). We analyzed demographic, clinical, laboratory data and echocardiographic findings. We also plotted the variation in trends between survivors and nonsurvivors. Results: Of the 34 critically ill children referred to PICU with diagnosis of MIS-C only 17 fulfilled the WHO/CDC classification of MIS-C, rest were MISC mimickers albeit other tropical infections. Median age at admission was 4 years (range 1y 6 mo-8 years). Fever, rash and conjunctival redness were most prominent symptoms. Myocardial involvement was seen in 70.5% while 76.4% developed shock; Invasive mechanical ventilation was required in 64.7% cases. Inflammatory markers showed a downward trend such as-median C- reactive protein (mg/L) had a serial reduction in levels-from (median/IQR) 210 (132.60, 246.90) at admission to 52.3 (42, 120) on Day 3. Median Ferritin (ng/ml) (n = 12) was 690 (203, 1324), serum LDH (IU/L) (n = 12) was 505 (229.5, 1032) and Mean D-dimer (ng/ml) (n = 7) was 5093.85 (1991.65), suggestive of hyperinflammatory syndrome. Twelve patients received intravenous immune globulin, with adjunctive steroid therapy used in two third of the cases. Six children died, 4 of them were under-5 years of age. Tocilizumab was prescribed in two children with high vasotrope inotrope score (VIS), cardiogenic shock and oxygenation index more than 15, both survived. Conclusions: Severe MIS-C has a heterogenous presentation, local or regional outbreaks of prevalent infectious diseases often lead to confusion and overdiagnosis. Higher proportion of mortality was seen in Under -5 children with MISC. Shock-like presentation, presence of myocardial dysfunction or nonsurvivor status is associated with higher trend of inflammatory markers and more profound multi-organ dysfunction. If disease progresses rapidly despite first line therapy (IvIg and steroids), use of Tocilizumab should be considered-as a rescue therapy under resource limitations in the absence of extracorporeal support.

MultiInflammatory Syndrome in Children: A View into Immune Pathogenesis from a Laboratory Perspective

BACKGROUND

Multiinflammatory syndrome in children (MIS-C) is a novel and rare inflammatory disorder associated with severe acute respiratory syndrome coronavirus 2 infection in school-age children. Reports in the past year have suggested a multisystem pathophysiology characterized by hyperinflammation, gastrointestinal distress, and cardiovascular complications. Clinical laboratory investigations, including routine blood testing for inflammatory (e.g., C-reactive protein, ferritin) and cardiac (e.g., troponin, brain natriuretic peptides) markers have provided insight into potential drivers of disease pathogenesis, highlighting the role of the laboratory in the differential diagnosis of patients presenting with similar conditions (e.g., Kawasaki disease, macrophage activating syndrome).

CONTENT

While few studies have applied high-dimensional immune profiling to further characterize underlying MIS-C pathophysiology, much remains unknown regarding predisposing risk factors, etiology, and long-term impact of disease onset. The extent of autoimmune involvement is also unclear. In the current review, we summarize and critically evaluate available literature on potential pathogenic mechanisms underlying MIS-C onset and discuss the current and anticipated value of various laboratory testing paradigms in MIS-C diagnosis and monitoring.

SUMMARY

From initial reports, it is clear that MIS-C has unique inflammatory signatures involving both adaptive and innate systems. Certain cytokines, inflammatory markers, and cardiac markers assist in the differentiation of MIS-C from other hyperinflammatory conditions. However, there are still major gaps in our understanding of MIS-C pathogenesis, including T cell, B cell, and innate response. It is essential that researchers not only continue to decipher initial pathogenesis but also monitor long-term health outcomes, particularly given observed presence of circulating autoantibodies with unknown impact.

Clinical aspects and presumed etiology of multisystem inflammatory syndrome in children (MIS-C): A review

The COVID-19 outbreak sparked by SARS-CoV-2, begat significant rates of malady worldwide, where children with an abnormal post-COVID ailment called the Multisystem Inflammatory Syndrome (MIS-C), were reported by April 2020. Here we have reviewed the clinical characteristics of the pediatric patients and the prognosis currently being utilized. A vivid comparison of MIS-C with other clinical conditions has been done. We have addressed the probable etiology and fundamental machinery of the inflammatory reactions, which drive organ failure. The involvement of androgen receptors portrays the likelihood of asymptomatic illness in children below adolescence, contributing to the concept of antibody-dependent enhancement.

Neutrophil Profiles of Pediatric COVID-19 and Multisystem Inflammatory Syndrome in Children

Multisystem Inflammatory Syndrome in Children (MIS-C) is a delayed-onset, COVID-19-related hyperinflammatory systemic illness characterized by SARS-CoV-2 antigenemia, cytokine storm and immune dysregulation; however, the role of the neutrophil has yet to be defined. In adults with severe COVID-19, neutrophil activation has been shown to be central to overactive inflammatory responses and complications. Thus, we sought to define neutrophil activation in children with MIS-C and acute COVID-19. We collected samples from 141 children: 31 cases of MIS-C, 43 cases of acute pediatric COVID-19, and 67 pediatric controls. We found that MIS-C neutrophils display a granulocytic myeloid-derived suppressor cell (G-MDSC) signature with highly altered metabolism, which is markedly different than the neutrophil interferon-stimulated gene (ISG) response observed in pediatric patients during acute SARS-CoV-2 infection. Moreover, we identified signatures of neutrophil activation and degranulation with high levels of spontaneous neutrophil extracellular trap (NET) formation in neutrophils isolated from fresh whole blood of MIS-C patients. Mechanistically, we determined that SARS-CoV-2 immune complexes are sufficient to trigger NETosis. Overall, our findings suggest that the hyperinflammatory presentation of MIS-C could be mechanistically linked to persistent SARS-CoV-2 antigenemia through uncontrolled neutrophil activation and NET release in the vasculature.

ONE SENTENCE SUMMARY

Circulating SARS-CoV-2 antigen:antibody immune complexes in Multisystem Inflammatory Syndrome in Children (MIS-C) drive hyperinflammatory and coagulopathic neutrophil extracellular trap (NET) formation and neutrophil activation pathways, providing insight into disease pathology and establishing a divergence from neutrophil signaling seen in acute pediatric COVID-19.

Transmembrane serine protease 2 and angiotensin-converting enzyme 2 anti-inflammatory receptors for COVID-19/inflammatory bowel diseases treatment

Inflammatory bowel diseases (IBD) refer to a subgroup of chronic, progressive, long-term, and relapsing inflammatory disorders. IBD may spontaneously grow in the colon, and in severe cases may result in tumor lesions such as invasive carcinoma in inflamed regions of the intestine. Recent epidemiological reports indicate that old age and underlying diseases such as IBD contribute to severity and mortality in patients with coronavirus disease 2019 (COVID-19). Currently, the ongoing COVID-19 pandemic caused serious morbidity and mortality worldwide. It has also been shown that the transmembrane serine protease 2 is an essential factor for viral activation and viral engulfment. Generally, viral entry causes a 'cytokine storm' that induces excessive generation of proinflammatory cytokines/chemokines including interleukin (IL)-6, IL-2, IL-7, tumor necrosis factor-α, and interferon-γ. Future research could concentrate on developing inflammatory immunological responses that are efficient to encounter COVID-19. Current analysis elucidates the role of inflammation and immune responses during IBD infection with COVID-19 and provides a list of possible targets for IBD-regulated therapies in particular. Data from clinical, in vitro, and in vivo studies were collected in English from PubMed, Google Scholar, Scopus, and the Cochrane library until May 2021.

Maternal COVID-19 Vaccination and Its Potential Impact on Fetal and Neonatal Development

Vaccines have been developed at "warp speed" to combat the COVID-19 pandemic caused by the SARS-CoV-2 coronavirus. Although they are considered the best approach for preventing mortality, when assessing the safety of these vaccines, pregnant women have not been included in clinical trials. Thus, vaccine safety for this demographic, as well as for the developing fetus and neonate, remains to be determined. A global effort has been underway to encourage pregnant women to get vaccinated despite the uncertain risk posed to them and their offspring. Given this, post-hoc data collection, potentially for years, will be required to determine the outcomes of COVID-19 and vaccination on the next generation. Most COVID-19 vaccine reactions include injection site erythema, pain, swelling, fatigue, headache, fever and lymphadenopathy, which may be sufficient to affect fetal/neonatal development. In this review, we have explored components of the first-generation viral vector and mRNA COVID-19 vaccines that are believed to contribute to adverse reactions and which may negatively impact fetal and neonatal development. We have followed this with a discussion of the potential for using an ovine model to explore the long-term outcomes of COVID-19 vaccination during the prenatal and neonatal periods.

Mental Health Issues During and After COVID-19 Vaccine Era

The COVID-19 pandemic has persisted for more than a year, and post-COVID-19 sequelae of neurological complications, including direct and indirect effects on the central nervous system (CNS), have been recognized. There is a plethora of evidence for neurological, cognitive, and emotional deficits in COVID-19 patients. Acute neurological symptoms like neuroinflammation, cognitive impairment, loss of smell, and brain stroke are common direct effects among SARS-CoV-2 infected individuals. Work-associated stress, lockdowns, social distancing, and quarantine in response to contain SARS-CoV-2 have also affected the mental health of large populations, regardless of age. Public health emergencies have affected individuals and communities, resulting in emotional reactions and unhealthy behaviors. Although vaccines have been widely distributed and administered among large populations, vaccine hesitancy still exists and may be due to apprehension about vaccine efficacy, preliminary trials, and associated side effects. This review highlights the impact of COVID-19 on the CNS by outlining direct and indirect effects and factors contributing to the decline in people's mental health throughout the COVID-19 pandemic both during and after vaccine administration. Furthermore, we also discuss reasons for vaccine hesitancy and why some groups of people are deprived of vaccines. Finally, we touched upon the social determinants of mental health and their impact on disadvantaged populations during times of crisis which may help policymakers set up some action plans to mitigate the COVID-19 mental health turmoil during this ongoing pandemic.

'Stay at home': Is it good or not for house dust mite sensitized children with respiratory allergies?

BACKGROUND

Lockdown was imposed for children for 75 days in Turkey to limit the spread of COVID-19. During this period, children have to stay indoors, which might probably increase their exposures to indoor allergens and pollutants. Besides, reduced exposures to respiratory tract infections and outdoor pollutants might be favorable outcomes of this lockdown period. We evaluated the effects of the lockdown on house dust mite (HDM)-sensitized children with respiratory allergies.

METHODS

Three-month clinical and medication data of 165 mild-moderate asthmatic children with or without allergic rhinitis (AR), who were grouped according to their HDM sensitization status, were retrieved from patient records. Demographics, asthma control tests, nasal visual analog scores, and outdoor air quality monitoring data were used for assessments in comparisons with the same period in the previous year.

RESULTS

Eighty-four patients had asthma, and 81 patients had asthma with AR. Sensitization to HDM was present in 61.8% of the children. Patients experienced reduced numbers of upper respiratory tract infections (P = .008) and reduced asthma exacerbations (P < .001) compared with the same period in the previous year. Asthma control tests were significantly improved (P < .001), and cumulative inhaled corticosteroid usages were significantly reduced (P < .001). Noteworthily, nasal symptoms were significantly worsened in HDM-sensitized asthmatics with AR (P < .001).

CONCLUSIONS

This study highlighted that reduction in respiratory tract infections and outdoor pollution may play roles in asthma control and prevent exacerbations despite continuous indoor allergen exposure. Besides, worsening of nasal symptoms in HDM-sensitized asthmatics with AR implies the importance of indoor avoidance measures for AR control.

Testing for and identification of Multisystem Inflammatory Syndrome in children in the pediatric emergency department

PURPOSE OF REVIEW

The current article summarizes updates on multisystem inflammatory syndrome in children (MIS-C) research and focuses on strategies to diagnose and manage these patients in the emergency department.

RECENT FINDINGS

MIS-C is an inflammatory syndrome that occurs approximately 4-5 weeks after severe acute respiratory syndrome coronavirus 2 infection. It is associated with symptoms such as fever, shock, abdominal pain, rash, and conjunctivitis along with laboratory abnormalities such as elevated inflammatory markers, coagulation factors, and cytokines. Patients fall into the following three subcategories: first, classic or incomplete Kawasaki; second, cardiogenic or distributive shock; or third, an inflammatory response that does not initially meet criteria of the other subcategories. Immediate treatment largely focuses on supportive care through fluid resuscitation and pressor support; however, inpatient management may also include intravenous immunoglobulin, steroids, anticoagulation and at times anti-inflammatory biologics.

SUMMARY

Overall fatality rate remains low and short-term research has demonstrated self-limited sequelae. Pediatricians should focus on the timely diagnosis and identification of this inflammatory disease via clinical findings and laboratory evidence to best treat these patients.

Antibody Responses in COVID-19: A Review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread worldwide as a severe pandemic. Although its seroprevalence is highly variable among territories, it has been reported at around 10%, but higher in health workers. Evidence regarding cross-neutralizing response between SARS-CoV and SARS-CoV-2 is still controversial. However, other previous coronaviruses may interfere with SARS-CoV-2 infection, since they are phylogenetically related and share the same target receptor. Further, the seroconversion of IgM and IgG occurs at around 12 days post onset of symptoms and most patients have neutralizing titers on days 14-20, with great titer variability. Neutralizing antibodies correlate positively with age, male sex, and severity of the disease. Moreover, the use of convalescent plasma has shown controversial results in terms of safety and efficacy, and due to the variable immune response among individuals, measuring antibody titers before transfusion is mostly required. Similarly, cellular immunity seems to be crucial in the resolution of the infection, as SARS-CoV-2-specific CD4+ and CD8+ T cells circulate to some extent in recovered patients. Of note, the duration of the antibody response has not been well established yet.

Symptoms, SARS-CoV-2 Antibodies, and Neutralization Capacity in a Cross Sectional-Population of German Children

Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, SARS-CoV-2 infection infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined. Results: We identified antibodies against SARS-CoV-2 in 162 of 2,832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n = 97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed. Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.