Multisystem Inflammatory Syndrome in Children and SARS-CoV-2 Serology

Pathogenic Connections in Post-COVID Conditions: What Do We Know in the Large Unknown? A Narrative Review

The coronavirus 2019 (COVID-19) disease has long-term effects, known as post-COVID conditions (PCC) or long-COVID. Post-COVID-19 syndrome is defined by signs and symptoms that occur during or after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection which persist for more than 12 weeks and cannot be supported by an alternative diagnosis. The cardiovascular damage caused by COVID-19 in the severe forms of the disease is induced by severe systemic inflammation, considered to be one of the causes of myocardial lesions, with increased levels of circulating cytokines and toxic response mediators. We have focused on conditions that can induce long-COVID-19, or multisystem inflammatory syndrome in adults or children (MIS-C/MIS-A), with an emphasis on endocrinological and metabolic disorders. Although described less frequently in children than in adults, long-COVID syndrome should not be confused with MIS-C, which is an acute condition characterized by multisystem involvement and paraclinical evidence of inflammation in a pediatric patient who tested positive for SARS-CoV-2. At the same time, we mention that the MIS-A symptoms remit within a few weeks, while the duration of long-COVID is measured in months. Long-COVID syndrome, along with its complications, MIS-A and MIS-C, represents an important challenge in the medical community. Underlying comorbidities can expose both COVID-19 adult and pediatric patients to a higher risk of negative outcomes not only during, but in the aftermath of the SARS-CoV-2 infection as well.

[Seroprevalence of SARS-CoV-2 among children and adolescents in Germany-an overview]

Hintergrund

SARS-CoV-2-Antikörperstudien ergänzen und erweitern die Erkenntnisse aus der Meldestatistik laborbestätigter COVID-19-Fälle um Informationen zu unentdeckten Fällen.

Ziel der Arbeit

Der vorliegende Beitrag fasst bisherige Ergebnisse zur SARS-CoV-2-Prävalenz aus seroepidemiologischen Studien in Deutschland zusammen, die sich auf Kinder und Jugendliche konzentrieren, und ergänzt die bereits vorliegende Übersicht zur Seroprävalenz bei Erwachsenen und speziell bei Blutspendenden in Deutschland.

Material und Methoden

Die Ergebnisse der Übersichtsarbeit beruhen auf einer fortlaufenden systematischen Recherche in Studienregistern, Literaturdatenbanken, von Preprint-Veröffentlichungen und Medienberichten seroepidemiologischer Studien in Deutschland sowie deren Ergebnissen.

Ergebnisse

Mit Stand 17.09.2021 sind uns 16 deutsche seroepidemiologische Studien, die sich auf Kinder und Jugendliche konzentrieren, bekannt geworden. Für 9 dieser Studien liegen Ergebnisse vor. Für fast alle untersuchten Settings lag die SARS-CoV-2-Seroprävalenz für Kinder im Kita- und Grundschulalter in der ersten COVID-19-Welle deutlich unter 1 % und für Jugendliche unter 2 %. Im Verlauf der Pandemie wurden höhere Seroprävalenzen von bis zu 8 % für Kinder im Grundschulalter ermittelt.

Diskussion

Ergebnisse von SARS-CoV-2-Antikörperstudien bei Kindern und Jugendlichen in Deutschland liegen bislang erst in geringem Umfang und basierend auf lokal-regionalen, nichtrepräsentativen Stichproben vor. In künftigen Studien gilt es, einerseits abzuschätzen, welcher Anteil der Kinder und Jugendlichen bereits eine Infektion hatte oder geimpft ist. Zum anderen gilt es, die Verbreitung körperlicher und psychischer Beeinträchtigungen im Nachgang einer Infektion zu untersuchen.

iciHHV-6 in a Patient With Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a serious, sometimes life-threatening late complication of coronavirus disease 2019 (COVID-19) with multiorgan involvement and evidence of immune activation. The pathogenesis of MIS-C is not known, nor is the pathogenesis of the severe organ damage that is the hallmark of MIS-C. Human herpesvirus 6 (HHV-6), the virus responsible for roseola, is a ubiquitous herpesvirus that causes close to universal infection by the age of 3 years. HHV-6 remains latent for life and can be activated during inflammatory states, by other viruses, and by host cell apoptosis. HHV-6 has been associated with end-organ diseases, including hepatitis, carditis, and encephalitis. In addition, ∼1% of people have inherited chromosomally integrated human herpesvirus 6 (iciHHV-6), which is HHV-6 that has been integrated into chromosomal telomeric regions and is transmitted through the germ line. iciHHV-6 can be reactivated and has been associated with altered immune responses. We report here a case of MIS-C in which an initial high HHV-6 DNA polymerase chain reaction viral load assay prompted testing for iciHHV-6, which yielded a positive result. Additional research may be warranted to determine if iciHHV-6 is commonly observed in patients with MIS-C and, if so, whether it may play a part in MIS-C pathogenesis.

Presumptive Neonatal Multisystem Inflammatory Syndrome in Children Associated with Coronavirus Disease 2019

OBJECTIVE

The study aimed to alert the neonatal community to the possibility of multisystem inflammatory syndrome in children (MIS-C) like disease in critically ill neonates born to mothers with coronavirus disease 2019 (COVID-19).

STUDY DESIGN

Diagnosis of MIS-C like disease was pursued after echocardiography showed severely depressed ventricular function and pathological coronary artery dilation in the setting of medically refractory multisystem organ failure and maternal COVID-19 infection. The neonate did not respond to standard medical therapy, and there was no alternative disease that could explain the clinical course. High index of clinical suspicion coupled with low risk of intravenous immunoglobulin (IVIG) prompted us to pursue IVIG administration even though the neonate did not meet classic criteria for MIS-C.

RESULT

Following treatment with IVIG, there was rapid clinical improvement. Ventricular function improved within 15 hours and coronary artery dilation resolved in 8 days. There was no recurrence of disease during follow-up.

CONCLUSION

COVID-19 associated MIS-C like disease has not been well described in neonates. As typical features may be conspicuously absent, a high index of suspicion is warranted in critically ill neonates born to mothers with COVID-19. Echocardiography may provide critical diagnostic information and narrow the differential diagnosis.

KEY POINTS

· COVID-19 associated MIS-C can present in neonates.. · Echocardiography is helpful in raising suspicion for MIS-C in neonates.. · Consider MIS-C in the differential diagnosis of ill neonates born to mothers with COVID-19..

Killed whole-genome reduced-bacteria surface-expressed coronavirus fusion peptide vaccines protect against disease in a porcine model

As the coronavirus disease 2019 (COVID-19) pandemic rages on, it is important to explore new evolution-resistant vaccine antigens and new vaccine platforms that can produce readily scalable, inexpensive vaccines with easier storage and transport. We report here a synthetic biology-based vaccine platform that employs an expression vector with an inducible gram-negative autotransporter to express vaccine antigens on the surface of genome-reduced bacteria to enhance interaction of vaccine antigen with the immune system. As a proof-of-principle, we utilized genome-reduced Escherichia coli to express SARS-CoV-2 and porcine epidemic diarrhea virus (PEDV) fusion peptide (FP) on the cell surface, and evaluated their use as killed whole-cell vaccines. The FP sequence is highly conserved across coronaviruses; the six FP core amino acid residues, along with the four adjacent residues upstream and the three residues downstream from the core, are identical between SARS-CoV-2 and PEDV. We tested the efficacy of PEDV FP and SARS-CoV-2 FP vaccines in a PEDV challenge pig model. We demonstrated that both vaccines induced potent anamnestic responses upon virus challenge, potentiated interferon-γ responses, reduced viral RNA loads in jejunum tissue, and provided significant protection against clinical disease. However, neither vaccines elicited sterilizing immunity. Since SARS-CoV-2 FP and PEDV FP vaccines provided similar clinical protection, the coronavirus FP could be a target for a broadly protective vaccine using any platform. Importantly, the genome-reduced bacterial surface-expressed vaccine platform, when using a vaccine-appropriate bacterial vector, has potential utility as an inexpensive, readily manufactured, and rapid vaccine platform for other pathogens.

Why It Is Important to Develop an Effective and Safe Pediatric COVID-19 Vaccine

The need to cope with the medical, social, and economic storm due to the new coronavirus 2019 (COVID-19) pandemic as quickly as possible has led to the very rapid development of a huge number of vaccines. All these vaccines have been mainly developed in healthy adults and, in some cases, in the elderly. Children were marginally involved as, according to the clinical trial registry Clinical Trials.gov, only very few studies have included children among subjects to enroll, although just a few weeks after the pandemic declaration, the US Food and Drug Administration had highlighted the importance of vaccine evaluation in pediatrics. Availability of an effective and safe pediatric COVID-19 vaccine appears mandatory for several clinical and epidemiological reasons. However, as the development of an effective and safe pediatric vaccine seems far from easy, strong cooperation among governments, researchers, and pharmaceutical companies is highly desirable.