Investigation into cases of hepatitis of unknown aetiology among young children, Scotland, 1 January 2022 to 12 April 2022

Distinct Patterns of Liver Chemistry Changes in Pediatric Acute Hepatitis of Unknown Origin and COVID-19 Patients: A Systematic Review

In 2021 and 2022, there were noted to be clusters of pediatric acute hepatitis of unknown origin (AHUO) occurring across the globe. While there was not necessarily a global increase in cases, understanding the pattern of liver injury in AHUO is crucial to properly identify cases of this unexplained phenomenon, especially since it occurred simultaneously with a global resurgence of COVID-19. The objective of this study was to contrast the patterns in liver-relevant biochemical data from COVID-19 patients and AHUO. Studies reporting liver chemistries for cases of AHUO and COVID-19 were identified by a systematic review and search of the literature. For each case, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, direct bilirubin, and international normalized ratio (INR) levels were extracted as available. These were normalized to multiples of the upper limit of normal by patient age. There were statistically significant greater elevations of ALT and AST in patients with AHUO than in those with COVID-19. Only a subset of patients with COVID-19 had an AST or ALT greater than the normal range. INR elevation could be substantial for both conditions but was also statistically higher in the AHUO group. Liver chemistry changes were not statistically correlated with age. The pattern of liver chemistry changes between AHUO and COVID-19 have some distinctions, which suggests that AHUO is not a phenomenon driven primarily by SARS-CoV-2 infection alone. Differentiating AHUO and COVID-19 would be challenging based on patterns of liver chemistry changes alone.

Ferulic acid protects against gamma-radiation induced liver injury via regulating JAK/STAT/Nrf2 pathways

This study aims to evaluate the effect and underlying mechanism of ferulic acid (FA) in alleviating the acute liver injury by ionizing radiation (IR) in vivo. Rats were divided into 4groups (Groups: control, 6Gy irradiated (IRR), FA (50 mg/kg) and FA + IRR). The results showed that FA can effectively inhibit liver damage and restore the structure and function of the liver. In mechanism, FA prevented IR-induced liver fibrosis and blocked the JAK/STAT signaling pathway to effectively inhibit the hepatic inflammatory response; and inhibited IR-induced oxidative stress (OS) by upregulating the Nrf2 signaling pathway and promoting the synthesis of several antioxidants. Moreover, FA inhibited ferroptosis in the liver by stimulating the expression of GPX4 and SLC7A11. FA reduced lipid peroxidation by downregulation of the reactive oxygen species (ROS) production and iron aggregation, thus inhibiting ferroptosis and alleviating IR-induced liver injury. In conclusion, the current study suggests the potential complex mechanisms underlying the mitigating impact of FA in IR-induced ferroptotic liver damage.

Liver abnormalities following SARS-CoV-2 infection in children 1 to 10 years of age

OBJECTIVE

Beginning in October 2021 in the USA and elsewhere, cases of severe paediatric hepatitis of unknown aetiology were identified in young children. While the adenovirus and adenovirus-associated virus have emerged as leading aetiological suspects, we attempted to investigate a potential role for SARS-CoV-2 in the development of subsequent liver abnormalities.

DESIGN

We conducted a study using retrospective cohorts of deidentified, aggregated data from the electronic health records of over 100 million patients contributed by US healthcare organisations.

RESULTS

Compared with propensity score matched children with other respiratory infections, children aged 1-10 years with COVID-19 had a higher risk of elevated transaminases (HR (95% CI) 2.16 (1.74 to 2.69)) or total bilirubin (HR (95% CI) 3.02 (1.91 to 4.78)), or new diagnoses of liver diseases (HR (95% CI) 1.67 (1.21 to 2.30)) from 1 to 6 months after infection. Patients with pre-existing liver abnormalities, liver abnormalities surrounding acute infection, younger age (1-4 years) or illness requiring hospitalisation all had similarly elevated risk. Children who developed liver abnormalities following COVID-19 had more pre-existing conditions than those who developed abnormalities following other infections.

CONCLUSION

These results indicate that SARS-CoV-2 may prime the patient for subsequent development of liver infections or non-infectious liver diseases. While rare (~1 in 1000), SARS-CoV-2 is a risk for subsequent abnormalities in liver function or the diagnosis of diseases of the liver.

Demystifying the global outbreak of severe acute hepatitis of unknown aetiology in children: A systematic review and meta-analysis

BACKGROUND

The sudden outbreak of severe acute hepatitis of unknown aetiology (SAHUA) in the first half of 2022 affected more than 1010 children in 35 countries worldwide. Dire clinical outcomes, such as acute liver failure necessitating transplantation, neurological symptoms, long-term sequelae, and death, highlight the need to determine the pathogenesis of this condition. Hypotheses on the aetiology include adenovirus and SARS-CoV-2 infections and an aberrant immune response to multiple pathogen exposure following lifting of lockdown measures but further investigation is required to reach an informed consensus.

METHODS

A literature search was performed on MEDLINE and EMBASE in accordance with PRISMA guidelines for systematic reviews. Primary studies reporting data on severe acute hepatitis of unknown aetiology in children from the COVID-19 era were selected for inclusion in our review. Data on patient demographics, clinical presentation and outcomes, and diagnostic testing for coinfection were extracted. Meta-analysis used a random-effects model.

RESULTS

The 33 included studies (30 case series and 3 case-control studies) described a total of 3636 cases of SAHUA (reported 1 January, 2019-31 December, 2022), with a median age of 3.5 years. Of these, 214 children (5.9%) received a liver transplant and 66 (1.8%) died. Whilst data on diagnostic testing was incomplete, the most frequently detected coinfections were with adenovirus and/or adeno-associated virus 2 (AAV2). Other common childhood respiratory and enteric pathogens, such as enterovirus, rhinovirus, and herpesviruses (EBV and HHV-6), were also identified.

CONCLUSION

Coinfection with AAV2 and other common childhood pathogens may predispose children to develop this novel severe hepatitis. Altered susceptibility and response to such pathogens may be a consequence of immunological naivety following pandemic restrictions. Further investigations are needed to generate high-quality evidence on aetiology for different patient demographics and geographical areas.

Could Herpesviridae be the cause of severe acute hepatitis of unknown origin in children?

INTRODUCTION

Severe acute hepatitis (SAH) is defined by a severe inflammation of hepatocytes in the liver parenchyma which can lead to an acute liver failure, a clinical condition with high mortality rate that can be triggered by several factors but is usually associated to hepatotropic viruses' infection. In 2022, cases of children with severe acute hepatitis of unknown origin hospitalized in Glasgow, Scotland, were reported. Possible causes of this condition include, but are not limited to, undiagnosed viral (and non-viral) infections, autoimmune hepatitis, drug and/or chemical toxicity, mitochondrial chain respiratory and metabolic disorders.

AREAS COVERED

Herpesviruses can cause severe acute hepatitis, but little is known about the role and the mechanisms of herpesviruses as a causative agent of this type of hepatitis. We review the role of herpesviruses as causative agent of SAH in children and other possible mechanisms involved in this disease.

EXPERT OPINION

Differential diagnosis for herpesvirus in SAH should be implemented in all settings. Alternative fluids, such as saliva and dried blood, could be used in the diagnosis to overwhelm the availability of biological specimens at sufficient volume. In the future, genetic studies could also be added to increase the knowledge about severe acute hepatitis in children.

Paediatric acute hepatitis of unknown aetiology: a national investigation and adenoviraemia case-control study in the UK

BACKGROUND

An increase in acute severe hepatitis of unknown aetiology in previously healthy children in the UK in March, 2022, triggered global case-finding. We aimed to describe UK epidemiological investigations of cases and their possible causes.

METHODS

We actively surveilled unexplained paediatric acute hepatitis (transaminase >500 international units per litre) in children younger than 16 years presenting since Jan 1, 2022, through notifications from paediatricians, microbiologists, and paediatric liver units; we collected demographic, clinical, and exposure information. Then, we did a case-control study to investigate the association between adenoviraemia and other viruses and case-status using multivariable Firth penalised logistic regression. Cases aged 1-10 years and tested for adenovirus were included and compared with controls (ie, children admitted to hospital with an acute non-hepatitis illness who had residual blood samples collected between Jan 1 and May 28, 2022, and without known laboratory-confirmed diagnosis or previous adenovirus testing). Controls were frequency-matched on sex, age band, sample months, and nation or supra-region with randomised selection. We explored temporal associations between frequency of circulating viruses identified through routine laboratory pathogen surveillance and occurrence of cases by linear regression. SARS-CoV-2 seropositivity of cases was examined against residual serum from age-matched clinical comparison groups.

FINDINGS

Between Jan 1 and July 4, 2022, 274 cases were identified (median age 3 years [IQR 2-5]). 131 (48%) participants were male, 142 (52%) were female, and one (<1%) participant had sex data unknown. Jaundice (195 [83%] of 235) and gastrointestinal symptoms (202 [91%] of 222) were common. 15 (5%) children required liver transplantation and none died. Adenovirus was detected in 172 (68%) of 252 participants tested, regardless of sample type; 137 (63%) of 218 samples were positive for adenovirus in the blood. For cases that were successfully genotyped, 58 (81%) of 72 had Ad41F, and 57 were identified as positive via blood samples (six of these were among participants who had undergone a transplant). In the case-control analysis, adenoviraemia was associated with hepatitis case-status (adjusted OR 37·4 [95% CI 15·5-90·3]). Increases in the detection of adenovirus from faecal samples, but not other infectious agents, in routine laboratory pathogen surveillance correlated with hepatitis cases 4 weeks later, which independently suggested an association (β 0·06 [95% CI 0·02-0·11]). No association was identified for SARS-CoV-2 antibody seropositivity.

INTERPRETATION

We observed an association between adenovirus 41F viraemia and paediatric acute hepatitis. These results can inform diagnostic testing recommendations, clinical management, and exploratory in vitro or clinical studies of paediatric acute hepatitis of unknown aetiology. The role of potential co-factors, including other viruses and host susceptibility, requires further investigation.

FUNDING

None.

Paediatric acute hepatitis of unknown aetiology: a national surveillance investigation in the USA during 2021 and 2022

BACKGROUND

Adenovirus is a known cause of hepatitis in immunocompromised children, but not in immunocompetent children. In April, 2022, following multiple reports of hepatitis of unknown aetiology and adenovirus viraemia in immunocompetent children in the USA and UK, the US Centers for Disease Control and Prevention (CDC) and jurisdictional health departments initiated national surveillance of paediatric acute hepatitis of unknown aetiology. We aimed to describe the clinical and epidemiological characteristics of children identified with hepatitis of unknown aetiology between Oct 1, 2021, and Sept 30, 2022, in the USA and to compare characteristics of those who tested positive for adenovirus with those who tested negative.

METHODS

In this national surveillance investigation in the USA, children were identified for investigation if they were younger than 10 years with elevated liver transaminases (>500 U/L) who had an unknown cause for their hepatitis and onset on or after Oct 1, 2021. We reviewed medical chart abstractions, which included data on demographics, underlying health conditions, signs and symptoms of illness, laboratory results, vaccination history, radiological and liver pathology findings, diagnoses and treatment received, and outcomes. Caregiver interviews were done to obtain information on symptoms and health-care utilisation for the hepatitis illness, medical history, illness in close contacts or at school or daycare, diet, travel, and other potential exposures. Blood, stool, respiratory, and tissue specimens were evaluated according to clinician discretion and available specimens were submitted to CDC for additional laboratory testing or pathology evaluation.

FINDINGS

Surveillance identified 377 patients from 45 US jurisdictions with hepatitis of unknown aetiology with onset from Oct 1, 2021, to Sept 30, 2022. The median age of patients was 2·8 years (IQR 1·2-5·0) and 192 (51%) were male, 184 (49%) were female, and one patient had sex unknown. Only 22 (6%) patients had a notable predisposing underlying condition. 347 patients (92%) were admitted to hospital, 21 (6%) subsequently received a liver transplant, and nine (2%) died. Among the 318 patients without notable underlying conditions, 275 were tested for adenovirus. Of these 116 (42%) had at least one positive specimen, and species F type 41 was the most frequent type identified (19 [73%] of 26 typed specimens were HAdV-41). Proportions of patients who had acute liver failure, received a liver transplant, and died were similar between those who tested positive for adenovirus compared with those who tested negative. Adenovirus species F was detected by polymerase chain reaction in nine pathology liver evaluations, but not by immunohistochemistry in seven of the nine with adequate liver tissue available. Interviews with caregivers yielded no common exposures.

INTERPRETATION

Adenovirus, alone or in combination with other factors, might play a potential role in acute hepatitis among immunocompetent children identified in this investigation, but the pathophysiologic mechanism of liver injury is unclear. To inform both prevention and intervention measures, more research is warranted to determine if and how adenovirus might contribute to hepatitis risk and the potential roles of other pathogens and host factors.

FUNDING

None.

Non-A to E hepatitis in children: Detecting a novel viral epidemic during the COVID-19 pandemic

During the COVID-19 pandemic, two further novel viral epidemics were described in 2022, monkeypox virus infections in men having sex with men and non-A to E hepatitis in children. The latter occurred in the first half of 2022 with about 1000 cases worldwide, necessitating liver transplantation in 5% and causing death in 2% of patients. It took some effort to clarify the cause of the novel hepatitis epidemic. Researchers were confronted with a polymicrobial viral infection consisting of an adenovirus-associated virus type 2 (AAV2) infection, co-occurring with either human adenovirus type 41 (HAdV41) or herpesvirus infections; most prominently human herpesvirus type 6 (HHV-6). AAV-2, a small Dependovirus of the Parvovirus family, needs these helper viruses for its replication. AAV2 is used as a vector for liver-targeting gene therapy but was not previously known to cause acute hepatitis. HAdV41 and HHV-6 are mostly known to cause diarrhoea and febrile illnesses associated with skin rashes in children, respectively. Except for a few case reports of HHV-6 hepatitis, HAdV and HHV-6 are mostly known as major pathogens in immunosuppressed transplantation patients. A potential role of SARS-CoV-2 has also been discussed but the most popular hypothesis involves an indirect role of the COVID-19 pandemic for this novel disease. Exposure to HHV-6 infections occurs nearly quantitatively during the first year of life. Social distancing measures, followed by the lifting of these measures in 2022 might have caused a delayed exposure to multiple, normally benign childhood viral infections eliciting a dysregulated immune response with pathological effects for liver cells. In the fall of 2022, when these conditions were not longer met, case numbers dwindled. The hypothesis of an unequilibrated immune response instead of intrinsic cytopathic activity of the implicated viruses is further supported by the enrichment of a particular HLA allele in cases over controls.

Liver abnormalities following SARS-CoV-2 infection in children under 10 years of age

Objective

Beginning in October 2021 in the US and elsewhere, cases of severe pediatric hepatitis of unknown etiology were identified in young children. While the adenovirus and adenovirus-associated virus have emerged as leading etiologic suspects, we attempted to investigate a potential role for SARS-CoV-2 in the development of subsequent liver abnormalities.

Design

We conducted a study utilizing retrospective cohorts of de-identified, aggregated data from the electronic health records of over 100 million patients contributed by US health care organizations.

Results

Compared to propensity-score-matched children with other respiratory infections, children aged 1-10 years with COVID-19 had a higher risk of elevated transaminases (Hazard ratio (HR) (95% Confidence interval (CI)) 2.16 (1.74-2.69)) or total bilirubin (HR (CI) 3.02 (1.91-4.78)), or new diagnoses of liver diseases (HR (CI) 1.67 (1.21-2.30)) from one to six months after infection. Patients with pre-existing liver abnormalities, liver abnormalities surrounding acute infection, younger age (1-4 years), or illness requiring hospitalization all had similarly elevated risk. Children who developed liver abnormalities following COVID-19 had more pre-existing conditions than those who developed abnormalities following other infections.

Conclusion

These results indicate that SARS-CoV-2 may prime the patient for subsequent development of liver infections or non-infectious liver diseases. While rare (~1 in 1,000), SARS-CoV-2 is a risk for subsequent abnormalities in liver function or the diagnosis of diseases of the liver.

What is already known on this topic

Clusters of severe hepatitis in children in 2022 coincident with the increase in COVID-19 infections in children raised the question of the contribution of SARS-CoV-2 to the hepatitis outbreak, though it was soon determined that SARS-CoV-2 was not the primary etiologic agent.

What this study adds

SARS-CoV-2 may prime the patient for subsequent development of liver infections or non-infectious liver diseases.

How this study might affect research practice or policy

Despite the mild initial disease in children, there may be longer term consequences of COVID-19, such as liver abnormalities, that warrants further investigation.

Task Force for a rapid response to an outbreak of severe acute hepatitis of unknown aetiology in children in Portugal in 2022

On 5 April 2022, the United Kingdom reported an increase of cases of severe acute hepatitis of unknown aetiology in children, several needing hospitalisation and some required liver transplant or died. Thereafter, 35 countries reported probable cases, almost half of them in Europe. Facing the alert, on 28 April, Portugal created a multidisciplinary Task Force (TF) for rapid detection of probable cases and response. The experts of the TF came from various disciplines: clinicians, laboratory experts, epidemiologists, public health experts and national and international communication. Moreover, Portugal adopted the European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO) case definition and recommendations. By 31 December 2022, 28 probable cases of severe acute hepatitis of unknown aetiology were reported: 16 male and 17 aged under 2 years. Of these cases, 23 were hospitalised but none required liver transplant or died. Adenovirus was detected from nine of 26 tested cases. No association was observed between adenovirus infection and hospital admission after adjusting for age, sex and region in a binomial regression model. The TF in Portugal may have contributed to increase awareness among clinicians, enabling early detection and prompt management of the outbreak.

Signatures of AAV-2 immunity are enriched in children with severe acute hepatitis of unknown etiology

Severe acute hepatitis of unknown etiology in children is under investigation in 35 countries. Although several potential etiologic agents have been investigated, a clear cause for the liver damage observed in these cases remains to be identified. Using VirScan, a high-throughput antibody profiling technology, we probed the antibody repertoires of nine cases of severe acute hepatitis of unknown etiology treated at Children's of Alabama and compared their antibody responses with 38 pediatric and 470 adult controls. We report increased adeno-associated dependoparvovirus A (AAV-A) breadth in cases relative to controls and adeno-associated virus 2 (AAV-2) peptide responses that were conserved in seven of nine cases but rarely observed in pediatric and adult controls. These findings suggest that AAV-2 is a likely etiologic agent of severe acute hepatitis of unknown etiology.

Adenovirus F41 infection and liver cytolysis in adult hematopoietic stem cell transplant recipients

Human adenoviruses (HAdVs) of the F species are commonly responsible for acute gastroenteritis. A few cases of systemic infections have been described in adults or children who have received a hematopoietic stem cell transplant (HSCT), but with no report of liver cytolysis. Since January 2022, several countries have reported an increase in cases of acute hepatitis of unknown cause in children. Adenovirus species F type 41 (HAdV-F41) infection was predominantly identified. The objective of this study is to describe HAdV-F41 infections diagnosed since January 2022 in adult HSCT recipients in two French hospitals. All four patients had diarrhea and liver cytolysis at the time of diagnosis of infection. HAdV viremia was observed in three patients (#1, #3, and #4), but no disseminated disease was reported. HAdV whole genome sequencing and metagenomics characterization were performed on stool and blood samples. The complete HAdV-F41 genome sequence was obtained for three patients and phylogenetic analysis showed that the strains consisted of similar lineage (2b). We did not identify any new HAdV-F41 strains. Metagenomics analysis found adeno-associated virus 2 and torque-teno virus infection in patient #1 and Epstein-Barr virus in patient #4. This is the first case series reporting liver cytolysis during HAdV-F41 infection in adult HSCT patients.

Higher convergence of human-great ape enteric eukaryotic viromes in central African forest than in a European zoo: a One Health analysis

Human-animal pathogenic transmissions threaten both human and animal health, and the processes catalyzing zoonotic spillover and spillback are complex. Prior field studies offer partial insight into these processes but overlook animal ecologies and human perceptions and practices facilitating human-animal contact. Conducted in Cameroon and a European zoo, this integrative study elucidates these processes, incorporating metagenomic, historical, anthropological and great ape ecological analyses, and real-time evaluation of human-great ape contact types and frequencies. We find more enteric eukaryotic virome sharing between Cameroonian humans and great apes than in the zoo, virome convergence between Cameroonian humans and gorillas, and adenovirus and enterovirus taxa as most frequently shared between Cameroonian humans and great apes. Together with physical contact from hunting, meat handling and fecal exposure, overlapping human cultivation and gorilla pillaging in forest gardens help explain these findings. Our multidisciplinary study identifies environmental co-use as a complementary mechanism for viral sharing.

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children.

Adeno-associated virus type 2 in US children with acute severe hepatitis

As of August 2022, clusters of acute severe hepatitis of unknown aetiology in children have been reported from 35 countries, including the USA1,2. Previous studies have found human adenoviruses (HAdVs) in the blood from patients in Europe and the USA3-7, although it is unclear whether this virus is causative. Here we used PCR testing, viral enrichment-based sequencing and agnostic metagenomic sequencing to analyse samples from 16 HAdV-positive cases from 1 October 2021 to 22 May 2022, in parallel with 113 controls. In blood from 14 cases, adeno-associated virus type 2 (AAV2) sequences were detected in 93% (13 of 14), compared to 4 (3.5%) of 113 controls (P < 0.001) and to 0 of 30 patients with hepatitis of defined aetiology (P < 0.001). In controls, HAdV type 41 was detected in blood from 9 (39.1%) of the 23 patients with acute gastroenteritis (without hepatitis), including 8 of 9 patients with positive stool HAdV testing, but co-infection with AAV2 was observed in only 3 (13.0%) of these 23 patients versus 93% of cases (P < 0.001). Co-infections by Epstein-Barr virus, human herpesvirus 6 and/or enterovirus A71 were also detected in 12 (85.7%) of 14 cases, with higher herpesvirus detection in cases versus controls (P < 0.001). Our findings suggest that the severity of the disease is related to co-infections involving AAV2 and one or more helper viruses.

Mori fructus aqueous extracts attenuates liver injury by inhibiting ferroptosis via the Nrf2 pathway

BACKGROUND

Liver fibrosis and hepatocellular carcinogenesis secondary to liver fibrosis are serious liver diseases with no effective treatments. Mori fructus aqueous extracts (MFAEs) have served as successful treatments for many types of liver injury including fibrosis although the molecular mechanisms are unknown at present.

PURPOSE

To investigate the effect of MFAEs in alleviating acute and chronic liver injury and tried to decipher the underlying mechanism.

METHODS AND RESULTS

Mice were divided into 5 groups (n = 8) for acute (groups: control, 0.3% CCl₄, bifendate (BD), 100 and 200 mg/kg MFAEs, 7 d) and chronic (groups: control, 10% CCl₄, BD, 100 and 200 mg/kg MFAEs, 4 weeks) liver injury study. Each mouse was injected intraperitoneally with 10 µL/g corn oil containing CCl₄ expect the control group. HepG2 cells were used in vitro study. Eighteen communal components were identified by UPLC-LTQ-Orbitrap-MS. We utilized a mouse model for acute and chronic liver injury using CCl₄ and MFAEs administration effectively blocked fibrosis and significantly inhibited inflammation in the liver. MFAEs activated the nuclear factor erythroid derived 2 like 2/heme oxygenase 1 (Nrf2/HO-1) pathway and promoted the synthesis of the antioxidants glutathione (GSH), superoxidedismutase (SOD) and glutathione peroxidase (GSH-Px) that resulted in reduced levels of CCl₄-induced oxidative stress molecules including reactive oxygen species. These extracts administered to mice also inhibited ferroptosis in the liver by regulating the expression of Acyl-CoA synthetase long chain family member 4 (ACSL4), solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), thus reducing the occurrence of liver fibrosis. Both in vivo and in vitro tests indicated that the mechanism of MFAEs protection against liver fibrosis was linked to activation of Nrf2 signaling. These effects were blocked in vitro by the addition of a specific Nrf2 inhibitor.

CONCLUSION

MFAEs inhibited oxidative stress, ferroptosis and inflammation of the liver by activating Nrf2 signal pathway and provided a significant protective effect against CCl₄-induced liver fibrosis.

May 2022 acute hepatitis outbreak, is there a role for COVID-19 and other viruses?

There has been an increasing number of reported cases of acute hepatitis of unknown origin in previously healthy children since first reported on March 31, 2022. This clinical syndrome is identified by jaundice and markedly elevated liver enzymes with increased aspartate transaminase and/or alanine aminotransaminase (greater than 500 IU/L). We conducted an inclusive literature review with respect to acute hepatitis outbreaks in children using the search terms acute hepatitis, outbreak, children, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), coronavirus disease 2019 (COVID-19), and adenovirus. According to the cumulative data presented in four main studies, the median age is 4 years, with a male predominance (1.3:1). Jaundice was the most common clinical manifestation (69%), followed by vomiting (63%), anorexia (52.9%), diarrhea (47.2%), abdominal pain (39%), pyrexia (33.3%), pale stool (30%), and dark urine (30%). Coryza and lethargy were reported in 16.6%, while pruritus was reported in 2% of cases. Acute liver failure was observed in 25% of cases. The exact mechanism of this acute hepatitis outbreak is still not entirely clear. Adenoviruses and SARS-CoV-2 were detected in a significant number of patients. Coinfection with adenovirus and SARS-CoV-2 could be a possible underlying mechanism. However, other possible infections and mechanisms must be considered in the pathogenesis of this condition. Acute hepatitis of unknown origin in children has been a serious problem since the start of the COVID-19 pandemic but has not yet been sufficiently addressed. Many questions remain regarding the underlying mechanisms leading to acute liver failure in children, and it is likely that extensive future research is needed.

Updated information regarding acute severe hepatitis of unknown origin in children: Viewpoints of and insights from pediatricians

Recently, the morbidity of acute severe hepatitis of unknown origin in children (SHIC) has tended to decrease, but this condition should not be ignored because of its uncertain but severe nature. The current study briefly summarizes updated information regarding the epidemiological, clinical, and etiological aspects of SHIC based on the newest information available. Opinions from pediatricians are also presented. In light of the status quo of SHIC and COVID-19 globally, several suggestions are proposed to improve future studies, which could help to further explore the underlying mechanisms of SHIC in the context of COVID-19.

The Changes in Respiratory and Enteric Adenovirus Epidemiology in Korea From 2017 to June 2022

Since October 2021, severe acute hepatitis of unknown etiology in pediatric patients has been observed in many countries around the world. Adenovirus (mainly enteric adenovirus) was detected in more than 50% of the cases. Nationwide surveillance on acute hepatitis of unknown etiology in pediatric patients was started in May 2022 in Korea. Taking into account the severity of the illness and the urgency of the epidemiological situation worldwide, we report a summary of changes in adenovirus epidemiology during the past five years and six months in Korea.

Sequencing directly from antigen-detection rapid diagnostic tests in Belgium, 2022: a gamechanger in genomic surveillance?

BackgroundLateral flow antigen-detection rapid diagnostic tests (Ag-RDTs) for viral infections constitute a fast, cheap and reliable alternative to nucleic acid amplification tests (NAATs). Whereas leftover material from NAATs can be employed for genomic analysis of positive samples, there is a paucity of information on whether viral genetic characterisation can be achieved from archived Ag-RDTs.AimTo evaluate the possibility of retrieving leftover material of several viruses from a range of Ag-RDTs, for molecular genetic analysis.MethodsArchived Ag-RDTs which had been stored for up to 3 months at room temperature were used to extract viral nucleic acids for subsequent RT-qPCR, Sanger sequencing and Nanopore whole genome sequencing. The effects of brands of Ag-RDT and of various ways to prepare Ag-RDT material were evaluated.ResultsSARS-CoV-2 nucleic acids were successfully extracted and sequenced from nine different brands of Ag-RDTs for SARS-CoV-2, and for five of these, after storage for 3 months at room temperature. The approach also worked for Ag-RDTs for influenza virus (n = 3 brands), as well as for rotavirus and adenovirus 40/41 (n = 1 brand). The buffer of the Ag-RDT had an important influence on viral RNA yield from the test strip and the efficiency of subsequent sequencing.ConclusionOur finding that the test strip in Ag-RDTs is suited to preserve viral genomic material, even for several months at room temperature, and therefore can serve as source material for genetic characterisation could help improve global coverage of genomic surveillance for SARS-CoV-2 as well as for other viruses.

Acute Hepatitis of Unknown Origin in Children: Two Cases in a Portuguese Hospital

Several cases of paediatric acute hepatitis of an unknown aetiology have been described in these last few months and in several countries worldwide. We present two patients, a 7-month-old girl and an 8-year-old boy, with gastrointestinal symptoms and lethargy, associated with elevation of transaminase levels. Serologies for hepatitis A-E virus and PCR test to SARS-CoV-2 were all negative. In the first case, an adenovirus serotype C could be isolated in a respiratory sample as well as cytomegalovirus (CMV) in the blood (100 copies/mL). In both children, there was a progressive decrease in the hepatic markers and symptomatic resolution, compatible with a good prognosis, also seen globally in most cases. To date, infection remains the most plausible cause to consider, especially when it is presumed to be linked to adenovirus. Other potential agents and causes are still being evaluated, thus emphasizing the importance of continuous epidemiological surveillance, notification, and detailed study of all hepatitis cases.

Liver Transaminases in Pediatric Adenovirus Infection-A Five-Year Study in Two Major Reference Centers from Romania

Human adenovirus causes infections with a very heterogeneous clinical picture, and children are often the most frequently affected group. Interest in adenovirus has increased with the 2022 outbreak of severe acute hepatitis of unknown etiology as human adenovirus was considered as one of the possible etiological agents. We conducted a retrospective study over a 5-year period in two major tertiary hospitals in the Romanian capital with the aim to characterize the clinical picture and the dynamics of liver function tests in children with confirmed adenovirus infection. The study included 1416 children with a median age of 1.1 years (IQR: 0.3, 2.3 years). Digestive symptoms were predominant in 95.2% of children, mainly diarrhea (90.5%) and vomiting (50.5%), and 38.0% had respiratory symptoms. Increased transaminases were identified in 21.5% of patients. Age over 1 year, lethargy, vomiting and dehydration significantly increased the odds of liver cytolysis independent of other risk factors such as chronic conditions or co-infections. Aspartate aminotransferase (AST) was more commonly increased compared to alanine aminotransferase (ALT). Only six children had transaminase increases above 500 U/L, three of which had co-infections with rotavirus, Epstein-Barr virus (EBV), or respiratory syncytial virus (RSV). Liver function tests should be part of routine monitoring for pediatric patients with adenovirus infection. The current study fills a gap in current knowledge related to the frequency and the extent of liver involvement in human adenovirus infection among pediatric patients.

Multiplex MinION sequencing suggests enteric adenovirus F41 genetic diversity comparable to pre-COVID-19 era

Human adenovirus F41 causes acute gastroenteritis in children, and has recently been associated with an apparent increase in paediatric hepatitis of unknown aetiology in the UK, with further cases reported in multiple countries. Relatively little is known about the genetic diversity of adenovirus F41 in UK children; and it is unclear what, if any, impact the COVID-19 pandemic has had on viral diversity in the UK. Methods that allow F41 to be sequenced from clinical samples without the need for viral culture are required to provide the genomic data to address these questions. Therefore, we evaluated an overlapping-amplicon method of sequencing adenovirus genomes from clinical samples using Oxford Nanopore technology. We applied this method to a small sample of adenovirus-species-F-positive extracts collected as part of standard care in the East of England region in January-May 2022. This method produced genomes with >75 % coverage in 13/22 samples and >50 % coverage in 19/22 samples. We identified two F41 lineages present in paediatric patients in the East of England in 2022. Where F41 genomes from paediatric hepatitis cases were available (n=2), these genomes fell within the diversity of F41 from the UK and continental Europe sequenced before and after the 2020-2021 phase of the COVID-19 pandemic. Our analyses suggest that overlapping amplicon sequencing is an appropriate method for generating F41 genomic data from high-virus-load clinical samples, and currently circulating F41 viral lineages were present in the UK and Europe before the COVID-19 pandemic.

Changing spatiotemporal patterns for hepatitis of unspecified aetiology in China, 2004-2021: a population-based surveillance study

Objectives

As global efforts continue toward the target of eliminating viral hepatitis by 2030, the emergence of acute hepatitis of unspecified aetiology (HUA) remains a concern. This study assesses the overall trends and changes in spatiotemporal patterns in HUA in China from 2004 to 2021.

Methods

We extracted the incidence and mortality rates of HUA from the Public Health Data Center, the official website of the National Health Commission of the People's Republic of China, and the National Notifiable Infectious Disease Surveillance System from 2004 to 2021. We used R software, ArcGIS, Moran's statistical analysis, and joinpoint regression to examine the spatiotemporal patterns and annual percentage change in incidence and mortality of the HUA across China.

Results

From 2004 to 2021, a total of 707,559 cases of HUA have been diagnosed, including 636 deaths. The proportion of HUA in viral hepatitis gradually decreased from 7.55% in 2004 to 0.72% in 2021. The annual incidence of HUA decreased sharply from 6.6957 per 100,000 population in 2004 to 0.6302 per 100,000 population in 2021, with an average annual percentage change (APC) reduction of -13.1% (p < 0.001). The same result was seen in the mortality (APC, -22.14%, from 0.0089/100,000 in 2004 to 0.0002/100,000 in 2021, p < 0.001). All Chinese provinces saw a decline in incidence and mortality. Longitudinal analysis identified the age distribution in the incidence and mortality of HUA did not change and was highest in persons aged 15-59 years, accounting for 70% of all reported cases. During the COVID-19 pandemic, no significant increase was seen in pediatric HUA cases in China.

Conclusion

China is experiencing an unprecedented decline in HUA, with the lowest incidence and mortality for 18 years. However, it is still important to sensitively monitor the overall trends of HUA and further improve HUA public health policy and practice in China.

Acute liver failure and unique challenges of pediatric liver transplantation amidst a worldwide cluster of adenovirus-associated hepatitis

Investigation into a recent cluster of acute hepatitis in children from the southeastern United States identified human adenovirus (HAdV) DNAemia in all 9 cases. Molecular genotyping in 5 of 9 (56%) children identified HAdV type 41 in all cases (100%). Importantly, 2 children from this cluster progressed rapidly to pediatric acute liver failure (PALF) and required liver transplantation. HAdV type 41, a known cause of self-limited gastroenteritis, has not previously been associated with severe cholestatic hepatitis and liver failure in healthy children. Adenovirus polymerase chain reaction assay and sequencing of amplicons performed on DNA extracted from formalin-fixed, paraffin-embedded liver tissue also identified adenovirus species F (HAdV type 40 or 41) in these 2 children with PALF. Transplant considerations and successful liver transplantation in such situations remain scarce. In this report, we describe the clinical course, laboratory results, liver pathology, and treatment of 2 children with PALF associated with HAdV type 41, one of whom developed secondary hemophagocytic lymphohistiocytosis. Their successful posttransplant outcomes demonstrate the importance of early multidisciplinary medical management and the feasibility of liver transplantation in some children with PALF and HAdV DNAemia.

Acute Hepatitis of Unknown Origin in Pediatric Age Group: Recent Outbreaks and Approach to Management

Acute hepatitis has always been a public health concern, but the recent clustering of cases in various parts of the world has drawn some special attention. The sudden rise in cases has mainly been among the pediatric population of around 35 countries around the world, including developed countries such as the United States, the United Kingdom, and European countries. The outbreaks have had a devastating impact, with around 10% of the affected patients developing liver failure. The clinical presentation of patients resembles any other case of acute hepatitis, with the major symptoms being: jaundice (68.8%), vomiting (57.6%), and gastrointestinal symptoms such as abdominal pain (36.1%) and nausea (25.7%). Interestingly, the cases have tested negative for hepatotropic viruses Hep A, B, C, and E, thus giving rise to the terms Hepatitis of Unknown Origin or non-HepA-E hepatitis. Many causes have been attributed to the disease, with major evidence seen for adenovirus and SARS-CoV-2. International agencies have stressed on establishing diagnostic and management protocols to limit these outbreaks. As the understanding has evolved over time, diagnostic and management faculties have found more shape. The current review was designed to comprehensively compile all existing data and whittle it down to evidence-based conclusions to help clinicians.

Hepatitis of unknown etiology in children: Current evidence and association

Two years after the coronavirus disease 2019 (COVID-19) pandemic, acute hepatitis of unknown etiology in children (AHUCD) began to be reported worldwide. The novel coronavirus and adenovirus were found in pathogen and antibody tests in AHUCD cases reported by the World Health Organization. Children are not exposed to the viruses that children are generally exposed to owing to COVID-19 infection preventive measures such as isolation and wearing masks; therefore, some researchers have speculated that this disease is related to reduced exposure to pathogens. Some scientists have also speculated that the disease is related to liver injury and adenoviral hepatitis, which are the sequelae of COVID-19. Some evidence also suggests a weak association between the disease and COVID-19 vaccination. Therefore, further research and investigation of the pathogenesis, preventive measures, and early treatment of hepatitis of unknown etiology are required. This study aimed to synthesize available evidence to further elucidate this disease in order to treat and prevent it effectively.

Case report: Severe acute hepatitis in a 22-month-old Chinese boy with Omicron sub-variant BA.2.38

The etiology of severe acute hepatitis (SAH) in children is various. We describe the first Chinese case of severe acute hepatitis in a 22-month-old boy with the mild illness of Omicron sub-variant BA.2.38. With the application of Compound Glycyrrhizin Injection (CGI), the patient gradually recovered from acute liver injury (ALI). This case highlights the possibility of severe ALI in children with the non-critical illness of SARS-CoV-2. The management of SAH associated with the pandemic presents challenges for clinicians, and follow-up is in need. The method of differential diagnosis using limited laboratory results is of great value to the clinicians.

Acute hepatitis of unknown origin in children: A combination of factors

On 5 April 2022, the World Health Organization was notified of 10 cases of severe acute hepatitis of unknown etiology in children under 10 years of age in the United Kingdom. Although the exact cause of a proportion of pediatric acute hepatitis and acute liver failure cases was unclear, the above event has caused widespread concern worldwide. As of 14 September 2022, approximately 1,296 probable cases of acute hepatitis of unknown etiology have been reported from 37 countries/regions, of which approximately 55 required or received liver transplantation and 29 died. Although the etiology of acute hepatitis of unknown origin in children remains unclear, many hypotheses have been proposed about the disease. Instead of individual factors such as "adenovirus infection," "SARS-CoV-2 related," and "Adeno-associated virus 2 with helper virus coinfection," it is more likely due to a combination of factors. Accordingly, there is an urgent need for more data and research to clarify the disease etiology. This review aims to provide a historical perspective of acute hepatitis of unknown etiology in children in the past decades and summarize the current hypothesis and evidence on this emerging disease.

A link between severe hepatitis in children and adenovirus 41 and adeno-associated virus 2 infections

Over the past few months there have been reports of severe acute hepatitis in several hundred, otherwise healthy, immunocompetent young children. Several deaths have been recorded and a relatively large proportion of the patients have needed liver transplants. Most of the cases, so far, have been seen in the UK and in North America, but it has also been reported in many other European countries, the Middle East and Asia. Most common viruses have been ruled out as a causative agent; hepatitis A virus (HAV), hepatitis B virus (HBV) and hepatitis C virus (HCV) were not detected, nor were Epstein–Barr virus (EBV), cytomegalovirus (CMV) and human immunodeficiency virus (HIV) in many cases. A small proportion of the children had been infected with SARS-CoV-2 but these seem to be in a minority; similarly, almost none of the children had been vaccinated against COVID-19. Significantly, many of the patients were infected with adenovirus 41 (HAdV-F41). Previously, HAdV-41 had not been linked to hepatitis and is usually considered to cause gastroenteritis in both immunocompetent and immunocompromised patients. In two most recent studies, adeno-associated virus 2 (AAV2) was detected in almost all patients, together with species C and F HAdVs and human herpesvirus 6B (HHV6B). Here, I discuss the possibility that a change in tropism of HAdV-41 and changes in AAV2 may be responsible for their links to acute hepatitis.

Use of Cidofovir for Safe Transplantation in a Toddler with Acute Liver Failure and Adenovirus Viremia

BACKGROUND

Since October 2021, there have been more than 500 cases of severe hepatitis of unknown origin in children reported worldwide, including 180 cases in the U.S. The most frequently detected potential pathogen to date has been adenovirus, typically serotype 41. Adenovirus is known to cause a self-limited infection in the immunocompetent host. However, in immunosuppressed individuals, severe or disseminated infections may occur.

METHOD

We present the case of a two-year-old female who presented with cholestatic hepatitis and acute liver failure (ALF). Work up for etiologies of ALF was significant for adenovirus viremia, but liver biopsy was consistently negative for the virus. The risk for severe adenoviral infection in the setting of anticipated immunosuppression prompted us to initiate cidofovir to decrease viral load prior to undergoing liver transplantation.

RESULT

Our patient received a successful liver transplant, cleared the viremia after 5 doses of cidofovir, and continues to maintain allograft function without signs of infection at the time of this report, 5 months posttransplant.

CONCLUSION

Recent reports of pediatric hepatitis cases may be associated with adenoviral infection although the exact relationship is unclear. There is the possibility of the ongoing SARS-CoV-2 environment, or other immunologic modifying factors. All patients presenting with hepatitis or acute liver failure should be screened for adenovirus and reported to state health departments. Cidofovir may be used to decrease viral load prior to liver transplantation, to decrease risk of severe adenoviral infection.

Acute hepatitis of unknown aetiology among children around the world

By 26 August 2022, the number of cases of acute hepatitis of unknown etiology (AHUA) has drastically increased to 1115 distributed in 35 countries that fulfill the World Health Organization definition. Several hypotheses on the cause of AHUA have been proposed and are being investigated around the world. In the recent United Kingdom (UK) report, human adenovirus (HAdV) with adeno-associated virus (AAV) co-infection is the leading hypothesis. However, there is still limited evidence in establishing the causal relationship between AHUA and any potential aetiology. The leading aetiology continues to be HAdV infection. It is reported that HAdV genomics is not unusual among the population in the UK, especially among AUHA cases. Expanding the surveillance of HAdV and AAV in the population and the environment in the countries with AUHA cases is suggested to be the primary action. Metagenomics should be used in detecting other infectious pathogens on a larger scale, to supplement the detection of viruses in the blood, stool, and liver specimens from AUHA cases. It is useful to develop a consensus-specific case definition of AHUA to better understand the characteristics of these cases globally based on all the collected cases.

Current knowledge about the outbreak of acute severe hepatitis of unknown origin among children

BACKGROUND AND AIM

A recent outbreak of acute severe hepatitis of unknown etiology (ASHep-UA) among children 16 years old and younger has aroused global concern. Initially reported in central Scotland, the disease has been notified in 35 countries and linked to 22 deaths as of 25 September 2022. This review aimed to provide current knowledge about the outbreak of ASHep-UA.

METHODS AND RESULTS

The websites of the World Health Organization, the UK Health Security Agency, the European Center for Disease Prevention and Control, the Centers for Disease Control and Prevention, and the PubMed database were searched, based on the search term "acute severe hepatitis of unknown etiology." The corresponding reports or literature previously released by the mentioned websites and database were integrated to obtain current information about ASHep-UA.

CONCLUSION

Even though the potential relevance between ASHep-UA and adenovirus, adeno-associated virus 2, and human herpes viruses was revealed, the etiology of ASHep-UA is still unknown. More effort should be made to explore whether ASHep-UA is caused by a novel virus or other environmental factors, to generate appropriate treatment strategies.

RELEVANCE TO PATIENTS

ASHep-UA has aroused global concern recently, which may lead to adverse outcomes such as liver transplants and death. The present review shares current development and information about the outbreak of acute severe hepatitis of unknown origin among children.

Wastewater Surveillance Captured an Increase in Adenovirus Circulation in Milan (Italy) during the First Quarter of 2022

The quantification and molecular characterization of the AdV genome in urban wastewater samples (WWSs) collected weekly at a wastewater treatment plant (WWTP) in Milan from 1 January 2021 (week 2021-01) to 1 May 2022 (week 2022-17) were performed. The concentration of the AdV genome was graphically compared with the AdV positive rate observed in the respiratory/gastrointestinal specimens from individuals hospitalized with acute respiratory/gastrointestinal infections collected from one of the major hospitals in Milan in the same time series. An increase in the AdV circulation in WWSs was seen from November 2021, peaking in March 2022 and overlapped with an increase in the AdV positive rate in respiratory/fecal samples from individuals hospitalized with acute respiratory/gastrointestinal infections. The molecular characterization of the hexon hypervariable region of loop 1 of AdV revealed the presence of the species F type 41 in WWSs collected from February 2022 to April 2022. The wastewater surveillance of AdV can provide crucial epidemiological characteristics regarding AdV, particularly where no clinical surveillance is ongoing. The increase in the AdV circulation in Milan both in WWSs and clinical samples temporally overlapped with the outbreak of severe acute pediatric hepatitis observed in Europe and needs to be better investigated.

Characterization of a Hepatitis Outbreak in Children, 2021 to 2022

IMPORTANCE

After a cluster of pediatric cases of hepatitis of unknown etiology were identified in Scotland in March 2022, the World Health Organization published an outbreak alert, and more than 1010 probable cases were reported. Some cases progressed to acute liver failure and required liver transplant. Although many patients had positive results for adenovirus on polymerase chain reaction testing from whole blood samples and/or reported recent COVID-19 infection (with or without seropositivity), the precise pathogenesis remains unclear despite the high potential morbidity of this condition.

OBJECTIVE

To summarize the currently available evidence regarding novel pediatric hepatitis of unknown etiology (or novel hepatitis), encompassing case numbers, testing, management, and outcomes.

EVIDENCE REVIEW

A rapid review of the literature from April 1, 2021, to August 30, 2022, aimed to identify all available published case series and case-control studies of novel hepatitis. The search included PubMed and references and citations of short-listed studies.

FINDINGS

A total of 22 available case series and case-control studies describing 1643 cases were identified, with 120 children (7.3%) receiving liver transplants and 24 deaths (1.5%). Outcome reporting and testing for adenovirus and SARS-CoV-2 was incomplete. Assessment of disease severity and management was mixed and results regarding testing for adenovirus and SARS-CoV-2 were inconsistent for both serological testing and testing of explant or biopsy liver samples. More recent studies suggest a more plausible role for adenovirus and/or adeno-associated virus 2.

CONCLUSIONS AND RELEVANCE

This systematic review without meta-analysis describes the challenge posed by hepatitis of unknown etiology in terms of investigation and management, with many cases progressing to acute liver failure. The lack of clarity regarding pathogenesis means that these children may be missing the potential for targeted therapies to improve outcomes and avert the need for transplant. Clinicians, immunologists, and epidemiologists must collaborate to investigate the pathogenesis of this novel hepatitis.

Advances in medical management of acute liver failure in children: promoting native liver survival

Paediatric acute liver failure (PALF) is defined as a biochemical evidence of acute liver injury in a child with no previous history of chronic liver disease characterised by an international normalised ratio (INR) of 1·5 or more unresponsive to vitamin K with encephalopathy, or INR of 2·0 or more with or without encephalopathy. PALF can rapidly progress to multiorgan dysfunction or failure. Although the transplant era has substantially changed the outlook for these patients, transplantation itself is not without risks, including those associated with life-long immunosuppression. Consequently, there has been an increased focus on improving medical management to prioritise bridging of patients to native liver survival, which is possible due to improved understanding of the underlying pathophysiology of multiorgan involvement in PALF. In this Review, we discuss recent advances in the medical management of PALF with an aim of reducing the need for liver transplantation. The Review will focus on the non-specific immune-mediated inflammatory response, extracorporeal support devices, neuromonitoring and neuroprotection, and emerging cellular and novel future therapeutic options.

Acute Hepatitis of Unknown Etiology Among Young Children: Research Agenda by the ESPGHAN Hepatology Committee

In April 2022, an increased incidence of acute hepatitis cases of unknown etiology among previously healthy children across the United Kingdom was described. Since, more than 270 cases from the United Kingdom and hundreds more from all across the world have been reported. The majority of affected children were younger than 6 years of age. The clinical presentation was nonspecific with diarrhea and vomiting usually preceding the appearance of jaundice, abdominal pain, nausea, and malaise. Approximately 5% have required liver transplantation. An infectious etiology has been considered likely given the epidemiological and clinical features of the reported cases. Between 50 and 60% of the children tested were diagnosed with adenovirus infection although a clear etiological connection has still to be demonstrated. No link with SARS-CoV-2 infection and COVID-19 vaccine was found. What is not clear to date is whether the high number of acute hepatitis cases reported is related to a true increase in incidence or heightened awareness following on from the initial reports from the United Kingdom. The Hepatology Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) developed a paper on the current outbreak of acute hepatitis of unknown etiology recognizing its importance and the need of approaching the current situation with a scientifically rigorous approach. The aims of the article are to summarize the current knowledge and to identify the most pertinent issues regarding the diagnosis and management of this condition and the research questions raised.

Long COVID-19 Liver Manifestation in Children

OBJECTIVES

Severe acute respiratory syndrome coronavirus 2, the novel coronavirus responsible for coronavirus disease (COVID-19), has been a major cause of morbidity and mortality worldwide. Gastrointestinal and hepatic manifestations during acute disease have been reported extensively in the literature. Post-COVID-19 cholangiopathy has been increasingly reported in adults. In children, data are sparse. Our aim was to describe pediatric patients who recovered from COVID-19 and later presented with liver injury.

METHODS

This is a retrospective case series study of pediatric patients with post-COVID-19 liver manifestations. We collected data on demographics, medical history, clinical presentation, laboratory results, imaging, histology, treatment, and outcome.

RESULTS

We report 5 pediatric patients who recovered from COVID-19 and later presented with liver injury. Two types of clinical presentation were distinguishable. Two infants aged 3 and 5 months, previously healthy, presented with acute liver failure that rapidly progressed to liver transplantation. Their liver explant showed massive necrosis with cholangiolar proliferation and lymphocytic infiltrate. Three children, 2 aged 8 years and 1 aged 13 years, presented with hepatitis with cholestasis. Two children had a liver biopsy significant for lymphocytic portal and parenchyma inflammation, along with bile duct proliferations. All 3 were started on steroid treatment; liver enzymes improved, and they were weaned successfully from treatment. For all 5 patients, extensive etiology workup for infectious and metabolic etiologies was negative.

CONCLUSIONS

We report 2 distinct patterns of potentially long COVID-19 liver manifestations in children with common clinical, radiological, and histopathological characteristics after a thorough workup excluded other known etiologies.

A review on acute, severe hepatitis of unknown origin in children: A call for concern

Hepatitis is defined as the inflammatory reaction of the liver parenchyma. It is either acute, which resolves within six months or may be chronic. An outbreak of severe, acute hepatitis of unknown origin in children was reported in nearly all World Health Organisation (WHO) regions except in the Africa. As per the recent update on the 26th of May, approximately 650 cases have met the WHO's probable criteria. While some are yet to be confirmed, the WHO warns that the figure may be underestimating the real situation. The observed clinical presentation includes outstanding immoderate levels of transaminases, vomiting from the previous presentation, pale/mild stools, and jaundice. So far, the viruses which can cause viral hepatitides, like Hepatitis A, B, C, D, and E, have not been detected in any of the identified cases. Some literature reported human enteric adenovirus type 41F in the majority of cases aged sixteen or younger, with few cases of co-infection with SARS-CoV-2. Currently, only several hypotheses have discussed the causality of the outbreak. However, no consensus has been reached. During this outbreak, it is important to adhere to both hand and body hygiene, general infection and control prevention strategies, and lastly, case presentation matching the criteria of case definition set by the WHO. Said identified cases should be reported to concerned health authorities on an urgent basis and must be kept under proper surveillance.

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Hepatitis is defined as the inflammatory reaction of the liver parenchyma. It is either acute, which resolves within six months or may be chronic.

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An outbreak of severe, acute hepatitis of unknown origin in children was reported in nearly all World Health Organisation (WHO) regions except in the Africa.

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Although extensive research has not been conducted on the rapidly-progressing AHUO in children, current literature has reported human enteric adenovirus type-41F in most cases aged sixteen or younger.

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Potential confounding coronavirus infection is one of several theories currently being considered in acute non-hepatitis A–E viral hepatitis origin.

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During this outbreak, it is important to adhere to both hand and body hygiene, general infection and control prevention strategies, and lastly, case presentation matching the criteria of case definition set by the WHO.

Acute hepatitis (Non Hepa A-E) of unknown origin among pediatrics

Several clusters and individual cases of acute hepatitis have been reported in the US, Europe and recently in Asia and Central America since October 2021. A laboratory investigation of the common viral hepatitis agents (HAV, HBV, HCV, HDV and HEV) yielded negative results prompting the use of the term "acute non HepA-E hepatitis" to describe this condition. As of 24 June of 2022, WHO have reported 920 probable cases of severe acute hepatitis of unknown origin among pediatrics in 33 countries in five WHO regions. Since the previous reports on 27 May 2022, 270 new probable cases have been increased, including from four new countries, some of whom were also found to be positive for SARS-CoV-2. All the patients showed symptoms such as vomiting, diarrhea, jaundice, and abdominal pain. The patients' liver enzymes were remarkably increased. No connection with SARS-CoV-2 or its vaccine has been found so far. However, the suspected cause is adenovirus, including its genomic variations, because its pathogenesis and laboratory investigations have been positively linked. Until further evidence emerges, hygiene precautions could be helpful to prevent its spread.

High population burden of Omicron variant (B.1.1.529) is associated with the emergence of severe hepatitis of unknown etiology in children

OBJECTIVES

To explore a potential country-based ecological link between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529) infection and an apparent current global outbreak of severe hepatitis of unknown etiology among children.

METHODS

We examined country-level statistical associations between reported detection of one or more unexplained severe hepatitis cases in children and the cumulative number of Omicron (B.1.1.529) cases in 38 Organisation for Economic Co-operation and Development (OECD) member countries plus Romania.

RESULTS

At least one focal hepatitis case was detected in 12 of the 39 countries included in our analysis. Numbers of confirmed Omicron cases reported in these 12 countries ranged from 4.4 to 11.9 million. Among the remaining 27 countries, this measure ranged from 0.5 to 5.5 million cases. Countries which reported focal hepatitis cases experienced higher precedent population burdens of Omicron cases relative to those which did not report any such hepatitis cases (p=0.013).

CONCLUSION

Prior exposure to Omicron variant (B.1.1.529) may be associated with an increased risk for severe hepatitis among children, indicating a critical need to conduct cofactor studies.

Revisiting the overlooked role of recycled sewage water in high-income countries in adenoviral outbreaks such as the “2022 pediatric hepatitis’ outbreak”

Background

On the 5th of April 2022, cases of adenovirus-induced hepatitis were reported in Scotland and then reached multiple parts of the world. While adenovirus normally presents with diarrhea, vomiting, and fever, these novel cases also resulted in the development of fulminant hepatitis in non-immunocompromised cases.

Main body

The responsible pathogen “Adenovirus 41” is an enterovirus. Enteroviruses are spread by the fecal-oral route and are resistant to drying. As such, they predominate in sewage water. Hepatitis is normally restricted to poorer countries, yet this new wave seems to be confined to mostly high-income countries in Europe and the USA. These countries treat and recycle a higher percentage of sewage water. We also propose that the fulminant nature of this strain could be due to either a cross-species mutation or the general decrease in trained immunity post-COVID-19 lockdown.

Short conclusion

Evidence strongly suggests that the link between these new hepatitis cases is recycled sewage water. This should warrant further investigations on the origin of this outbreak by re-visiting the role of recycled sewage water in causing such outbreak.

Potential protective benefits of Schisandrin B against severe acute hepatitis in children during the COVID-19 pandemic based on a network pharmacology analysis

Aims: Reports of hepatitis in children during the coronavirus disease 2019 (COVID-19) pandemic garnered worldwide attention. The most probable culprits are adenovirus and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). At present, the optimal symptomatic treatment consists of a combination of anti-COVID-19 and hepatitis symptom alleviators. Schisandrin B (SchB) has been known to have liver-protective properties for a long time, whereas anti-COVID-19 properties only recently have been discovered. In the case of COVID-19 with hepatitis of unknown origin, we used network pharmacology to explore the symptomatic therapy and protective effects of SchB. Main methods: The most probable protein targets of SchB were predicted in the SwissTargetPrediction database. The GeneCards, National Center for Biotechnology Information, and Online Mendelian Inheritance in Man databases were used to compile information on the diseases hepatitis, adenovirus, and SARS-CoV-2. Following the use of a Venn diagram viewer to identify intersection genes, we constructed a protein-protein interaction network and identified the core genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment, as well as molecular docking, were employed to highlight the mechanisms of SchB on hepatitis. Key findings: SchB contains 27 targets on adenovirus_hepatitis and 16 targets on SARS-CoV-2_hepatitis, with 12 shared genes. Both target populations clustered in viral infection and cancer pathways, as well as in processes such as kinase activity phosphatase, cell adhesion, and ATPase binding. These genes might be closely related to liver damage and membrane binding from adenovirus or SARS-CoV-2 infections. In addition, epidermal growth factor receptor, HSP90AA1, and MAPK1 were among the top five targets of both SchB SARS-CoV-2 hepatitis and SchB adenovirus hepatitis. Significance: SchB may target common protective targets and mechanisms against acute hepatitis caused by adenovirus or by SARS-CoV-2 in children during the COVID-19 pandemic. These findings indicate SchB's potential as a treatment for hepatitis of unknown origin.