Italian children seem to be spared from the mysterious severe acute hepatitis outbreak: A report by SIGENP Acute Hepatitis Group

Investigation of an outbreak of novel hepatitis of unknown aetiology in children and adolescents, Ireland, 2021 to 2023

An outbreak of severe acute hepatitis of unknown aetiology in children (HUAC) was reported by the United Kingdom (UK) in spring 2022. Within days, a corresponding increase was identified in Ireland. A multi-agency incident management team (IMT), led by the Health Protection Surveillance Centre (HPSC), established a national case definition, trawling questionnaire, testing protocol and communications plan. Between 1 October 2021 and 12 May 2023, 44 probable and three possible cases of HUAC were identified in Ireland with a median age of 3 years. Adeno-associated virus 2 (AAV2), detected in 18 of 31 probable cases, and SARS-CoV-2 antibodies in 22 of 37 of probable cases were the most common infectious agents, followed by human herpes virus 7 (18/33) and adenovirus (20/44). Immunological findings included the human leukocyte antigen (HLA) class II HLA-DRB1*04:01 allele in 17 of 32 cases. Autoantibodies were found in 15 of 40 patients. Our findings corroborate those of the UK, which suggested a link between HUAC and AAV2 and another virus, in children predisposed due to presence of a particular HLA class II type. Close collaboration with the UK, the European Centre for Disease Prevention and Control (ECDC) and World Health Organization (WHO) was invaluable in the investigation.

The clinical characteristics and SARS-CoV-2 infection in children of acute hepatitis with unknown aetiology: A meta-analysis and systematic review

The World Health Organization has issued a global alert on Acute Severe Hepatitis of Unknown Aetiology (AS-HEP-UA) since 23 April 2022,and there was still uncertainty regarding the association of AS-HEP-UA with SARS-CoV-2 as well as adenovirus. This study aimed to summarize the infection of SARS-CoV-2 and co-infections with adenovirus, as well as clinical features and outcomes in patients with AS-HEP-UA. PubMed, Embase, Web of Science, and the Cochrane Library were searched from 1 October 2021 to 8 December 2022 for studies about patients with AS-HEP-UA. This study was registered in the PROSPERO database (CRD42023385056). We has included 14 eligible articles. The main clinical features of AS-HEP-UA were jaundice (65%) and vomiting (59%), while other clinical features included diarrhea (45%), abdominal pain (37%), and fever (31%), roughly 10% of the children required liver transplantation. The overall positivity rate for SARS-CoV-2 was 21.6% (95% CI: 0.126-0.319), with 25.5% (95% CI: 0.161-0.358) for previous infections. The positivity rate for adenovirus infection was 58.6% (95% CI:0.429-0.736) while co-infection with SARS-CoV-2 was 17.5% (95% CI: 0.049-0.342). Moreover, we found that the positive rate of SARS-CoV-2 for this hepatitis outbreak was correlated with region by subgroup analysis. In conclusion, the positive rate of adenovirus was higher than SARS-CoV-2, and the relationship between AS-Hep-UA and COVID-19 is not significant. However, it cannot be excluded that the COVID-19 epidemic is an indirect causative agent of AS-Hep-UA, which requires a larger cohort of AS-Hep-UA patients to uncover additional findings.

Acute Hepatitis of Unknown Origin in Children: Analysis of 17 Cases Admitted to the Bambino Gesù Children's Hospital in Rome

This study described 17 cases of children admitted to the Bambino Gesù Children's Hospital with acute hepatitis of unknown origin between mid-April and November 2022. Following the World Health Organization's working case definition of probable cases, 17 children, with a median age of 2.1 years (interquartile range: 1.0-7.1), presenting with acute hepatitis non-AE, with serum transaminase >500 IU/L, were included in the study. A pre-specified set of microbiological tests was performed on different biological specimens for all pediatric patients. All patients resulted negative for the common hepatotropic viruses. The most common pathogen detected in blood specimens was human-herpes-virus-7 (52.9%). Adenovirus was detected more frequently in stool specimens (62.5%) than in respiratory (20.0%) or blood samples (17.6%). Regarding Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, one child tested positive two days after admission, while antibodies against spike and nucleoprotein were present in 82.3% of patients. A co-pathogen detection was observed in 94.1% of children. Overall, 16 children recovered without clinical complications, while one patient required liver transplantation. In these cases of acute hepatitis of unknown origin, adenovirus was mainly detected in stool samples. A co-pathogen detection was also frequently observed, suggesting that the etiology of this acute hepatitis is most probably multifactorial.

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.

Recent Increase in Incidence of Severe Acute Hepatitis of Unknown Etiology in Children is Associated with Infection with Adenovirus and Other Nonhepatotropic Viruses

OBJECTIVE

To evaluate whether the nature and severity of non-A-E severe acute hepatitis in children noted by the World Health Organization from late 2021 through early 2022 was indeed increased in 2021-2022 compared with prior years.

STUDY DESIGN

We performed a single-center, retrospective study to track the etiology and outcomes of children with non-A-E severe acute hepatitis in 2021-2022 compared with the prior 3-year periods (2018-2019, 2019-2020, and 2020-2021). We queried electronic medical records of children ≤16 years of age with alanine or aspartate aminotransferase levels of >500 IU. Data were analyzed for the periods of October 1, 2021, to May 1, 2022, and compared with the same time periods in 2018-2021.

RESULTS

Of 107 children meeting entry criteria, 82 cases occurred from October to May of 2018-2022. The average annual case number was 16.3 in 2018-2021 compared with a 2-fold increase (to 33) in 2021-2022 (P = .0054). Analyses of etiologies showed that this increase was associated with a higher number of children who tested positive for viruses (n = 16) when compared with the average of 3.7 for 2018-2021 (P = .018). Adenovirus (26.1%) and severe acute respiratory syndrome coronavirus-2 (10.3%) were the most frequently detected viruses in 2021-2022. Despite evidence of acute liver failure in 37.8% of children in the entire cohort and in 47% of those with viral infection, the overall survival rate was high at 91.4% and 88.9%, respectively.

CONCLUSIONS

The number of children with severe acute hepatitis in our center increased from 2021 to May 2022, with a greater frequency of cases associated with adenovirus, yet transplant-free survival remains high.

Pediatric Gastroenterology and Hepatology in Italy before and after the COVID-19: Lessons learned and management changes by SIGENP

Around the world, the 2019 Coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has raised serious public health problems and major medical challenges. The Italian Society of Pediatric Gastroenterology, Hepatology and Nutrition (SIGENP) published several papers on the impact of COVID-19 on the current management, diagnosis, and treatment of acute and chronic gastrointestinal, hepatic, immune-mediated, and functional disorders. The present article summarizes the most relevant SIGENP reports and consensus during and after the peak of the COVID-19 outbreak, including the diagnosis and treatment of inflammatory bowel disease (IBD), indications and timing of digestive endoscopy, and insights into the novel hepatitis.

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.