Human Adenovirus Infection Research Articles

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.

PREVALENCE OF HUMAN ADENOVIRUS IN PAEDIATRIC PATIENTS PRESENTING WITH ACUTE RESPIRATORY SYMPTOMS AT DIFFERENT HOSPITALS OF PAKISTAN

Background: Human Adenovirus (HAdV) is one of the most common causes of infection in children. HAdV commonly affects respiratory system, however can also involve other parts of the body like nervous system, eyes and urinary tract. The virus usually causes a mild infection of the lower and upper respiratory tract. Objective of the study was to find the prevalence of HAdV in paediatric patients presenting with Influenza like symptoms and severe acute respiratory illness across Pakistan. Methods: This cross-sectional study was conducted at the National Institute of Health, Islamabad. Respiratory swabs were collected from 389 children with age less than five years from 14 hospitals in different regions of Pakistan from October 1, 2017 to September 30, 2018. Patients’ demographics, signs and symptoms were recorded through a predesigned proforma while Real-time polymerase chain reaction (RT-PCR) was performed for respiratory samples. Results: Out of all 389 samples, HAdV was found in 25 (6.4%) cases. The proportion of HAdV obtained was greater in females 18 (4.6%) than male 7 (1.8%). The influenza-like illness in children attending outpatient department had a higher prevalence of HAdV 13(3.3%) compared to admitted children 12 (3.1%). Similarly, patients from one to 6 months of age had higher positive outcome than older children. Majority of positive patients were from Islamabad (2.0%) followed by Gilgit (1.8%), Azad Jammu Kashmir (1.0%), Multan (0.5%), and Karachi (0.5%). The most frequent signs and symptoms were cough, fever, sore throat, nasal congestion and shortness of breath. Conclusion: The present study concludes that HAdV infection is common in Pakistan especially in female patients aged 1–6 months. It’s crucial to improve the diagnosis of HAdV infections in our country to prevent complications associated with the virus. Furthermore, genetic analysis may help find different genotypes of HAdV circulating in Pakistan.

Adenoviruses in medicine: innocuous pathogen, predator, or partner.

The consequences of human adenovirus (HAdV) infections are generally mild. However, despite the perception that HAdVs are harmless, infections can cause severe disease in certain individuals, including newborns, the immunocompromised, and those with pre-existing conditions, including respiratory or cardiac disease. In addition, HAdV outbreaks remain relatively common events and the recent emergence of more pathogenic genomic variants of various genotypes has been well documented. Coupled with evidence of zoonotic transmission, interspecies recombination, and the lack of approved AdV antivirals or widely available vaccines, HAdVs remain a threat to public health. At the same time, the detailed understanding of AdV biology garnered over nearly 7 decades of study has made this group of viruses a molecular workhorse for vaccine and gene therapy applications.

Different Clinical Manifestations of Adenoviral Infection Confirmed Using Point-of-Care Testing in a Group of Hospitalized Children.

Objective: A restrospective analysis of the clinical picture (inflammatory markers, characteristics of fever, comorbidities) in different clinical manifestations of human adenovirus (HAdV) infections confirmed using point-of-care testing in a group of hospitalized children. Material and Methods: A total of 135 children with confirmed HAdV infections were divided into three groups according to their clinical symptoms: Group A—respiratory (n = 57), Group B—gastrointestinal (n = 40), and Griup C—mixed (n = 38). Results: Respiratory and mixed HAdV-infected patients, as compared with gastrointestinal HAdV-infected patients, were younger (median value (Me) and interquartile range (IQR) (months): 17 (12−30) and 17 (12−27) vs. 30 (16−50), p = 0.04), had a longer duration of fever (days): 3 (1−5) and 3 (1−4) vs. 1 (1−2), p = 0.01), and had higher C-reactive protein values (mg/L): 29.2 (10.4−69.1) and 28.7 (10.8−49.1) vs. <5 (<5−20.6), p < 0.001). There were no correlations between CRP levels and patient’s age, fever duration, the occurrence of acute otitis media and lower respiratory tract infection, and antibiotic treatment before admission. Conclusions: Patients with respiratory HAdV infections have fevers more often, the duration of the fever prior to admission is longer, and CRP levels are higher.

2197. Genomic Surveillance for Human Adenovirus Infections among Department of Defense Beneficiaries in the 2018-2019 Season

Abstract Background Human adenoviruses (family Adenoviridae, genus Mastadenovirus) (HAdV) species B, C and E cause acute respiratory illnesses (ARI). In particular, respiratory HAdV types 3, 4, 7, 11, 14, 21 and 55 were associated with ARI outbreaks in the US and in other countries. The risk of outbreaks can be effectively controlled by implementation of the live HAdV types 4 and 7 vaccines or mitigated by screening and preventive measures. Methods During the influenza season 2018 – 2019, the DoD Global Respiratory Pathogen Surveillance Program (DoDGRS) received 24,300 specimens from its surveillance network. In total, 322 (1.3%) respiratory specimens were positive for HAdV in molecular assays. HAdV samples that produced positive cytopathic effects (CPE) in subsequent viral cultivation were subjected to next-gen sequencing (NGS) for genome sequence assembly, HAdV genome typing, whole genome phylogeny, and sequence comparative analyses to identify sequence insertions, deletions and amino acid mutations. Results Out of 166 viral culture samples available for NGS, whole genome sequences were obtained for 161 isolates. A variety types of HAdV were identified, including HAdV-1 (N = 15), HAdV-2 (N = 26), HAdV-3 (N = 60), HAdV-4 (N = 13), HAdV-5 (N = 6), HAdV-6 (N = 3), HAdV-7 (N = 12), HAdV-14 (N = 10), HAdV-55 (N = 1), and HAdV-56 (N = 1). HAdV types 4, 7 and 14, which were reported causing ARI outbreaks in the US military and other congregate settings, were found in clustered cases in several US states. Comparative sequence analyses of these isolates revealed the emergence of novel genetic mutations despite the stability of adenovirus genomes. Conclusion Routine clinical respiratory pathogen diagnostics or molecular surveillance of respiratory diseases detect adenovirus without determination of HAdV type. Human adenoviruses are genetically diverse and can infect a number of tissues with severities varied from mild to fatal. Enhanced genomic surveillance of HAdV in the US and worldwide will shed light on prevalence, genetic divergence, and viral evolution of human adenoviruses and inform timely risk assessment and countermeasures. Disclosures All Authors: No reported disclosures.

CELO Fiber1 Knob Is a Promising Candidate to Modify the Tropism of Adenoviral Vectors.

Fowl adenovirus 4 (FAdV-4) has the potential to be constructed as a gene transfer vector for human gene therapy or vaccine development to avoid the pre-existing immunity to human adenoviruses. To enhance the transduction of FAdV-4 to human cells, CELO fiber1 knob (CF1K) was chosen to replace the fiber2 knob in FAdV-4 to generate recombinant virus F2CF1K-CG. The original FAdV4-CG virus transduced 4% human 293 or 1% HEp-2 cells at the multiplicity of infection of 1000 viral particles per cell. In contrast, F2CF1K-CG could transduce 98% 293 or 60% HEp-2 cells under the same conditions. Prokaryotically expressed CF1K protein blocked 50% transduction of F2CF1K-CG to 293 cells at a concentration of 1.3 µg/mL while it only slightly inhibited the infection of human adenovirus 5 (HAdV-5), suggesting CF1K could bind to human cells in a manner different from HAdV-5 fiber. The incorporation of CF1K had no negative effect on the growth of FAdV-4 in the packaging cells. In addition, CF1K-pseudotyped HAdV-41 could transduce HEp-2 and A549 cells more efficiently. These data indicated that CF1K had the priority to be considered when there is a need to modify adenovirus tropism.

Laboratory Diagnosis of Human Adenovirus associated with Respiratory Tract Infection in children

Human Adenovirus (HADV) is classified in Adenoviridae family, it is important viral pathogen of respiratory tract infection (RTIs) among children. This study aimed at detecting HADV infections among hospitalized children under 10 years old with respiratory tract infections in Salahaldin Governorate, in addition to compare different diagnostic methods for the detection of this virus.&#x0D; Nasopharyngel Swabs (NPS) and whole blood samples were taken from 400 hospitalized children between end of August 2013, to the end of May 2014, each sample was analyzed for HADV by real time –PCR, IgM and IgG specific to HADV determining from blood specimens in serum using Enzyme Immuno sorbent assay (ELISA) technique.&#x0D; Nasopharyngel Swab was more sensitive than the whole blood specimens for the detection of HADV and was identified in 3% by RT-PCR, in 72.2% by IgM – HADV antibodies, 83.1% by IgG-HADV antibodies.&#x0D; Autumn – Spring periods were considered as the most common time for HADV infection with peak in September and February.

Detection of human adenovirus among Iranian pediatric hospitalized patients suspected of COVID-19: epidemiology and comparison of clinical features.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children typically results in similar symptoms with other viral respiratory agents including human adenoviruses (HAdVs). Mixed HAdV and SARS-CoV-2 infection (co-infection) in children might result in enhanced or reduced disease severity compared with single infections. The present study aims to investigate the rate of SARS-CoV2 and HAdV infection and also their coinfection and compare the two infections regarding their laboratory and clinical characteristics at hospital admission. A total of 360 combined oropharyngeal and nasopharyngeal swab samples from hospitalized children were examined by real-time PCR for the existence of the SARS-CoV-2 and HAdVs. The symptoms, the clinical characteristics and laboratory findings were retrieved and compared in SARS-CoV-2 and HAdVs positive cases. Of the total 360 suspected COVID-19 hospitalized children, 45 (12.5%) and 19 (5.3%) specimens were PCR-positive for SARS-CoV-2 and HAdV respectively. SARS-CoV-2 and HAdV co-infection was detected in 4 cases (1.1%). Regarding symptoms at hospital admission, fever in SARS-CoV-2 positive group was significantly higher than that in HAdV positive group [34 (85%) vs. 7 (46.7%), p = 0.012]. However, percentages of cases with sore throat, headache, fatigue, lymphadenopathy and conjunctivitis in HAdV positive group were significantly higher than those in SARS-CoV-2 positive group. SARS-CoV-2 and HAdV co-infected children showed mild respiratory symptoms. The present study revealed that SARS-CoV-2 positive children often appear to have a milder clinical course than children with respiratory HAdV infection and children co-infected with SARSCoV-2 and HAdV had less-severe disease on presentation.

Molecular typing and epidemiology profiles of human adenovirus infection among children with severe acute respiratory infection in Huzhou, China.

Human adenoviruses (HAdVs) are prevalent worldwide and are a common cause of respiratory tract infection in people of all ages. However, little is known about HAdV infection among children with severe acute respiratory infection (SARI). The present study retrospectively analysed the molecular typing and epidemiological characteristics of HAdV-positive samples from children with SARI from January 2017 to December 2021 in Huzhou. The results showed that 89 (8·27%) of 1078 SARI paediatric patients were positive for HAdVs. Children <5 years of age accounted for 87·64% of the positive cases. The peak seasons for HAdV infection were the first quarter and the fourth quarter. In addition, HAdV-B and HAdV-C were circulating among paediatric patients with SARI, of which the B3 genotype (n = 30, 51·72%) was the most prevalent and was detected every year, indicating that B3 is the main epidemic strain in the Huzhou area, followed by C1 (n = 9, 15·52%), C2 (n = 7, 12·07%) and B7 (n = 5, 8·62%). These findings provide a benchmark for future epidemiology and prevention strategies for HAdVs.

Characterization of the conserved regions of E1A protein from human adenovirus for reinforcement of cytotoxic T lymphocytes responses to the all genogroups causes ocular manifestation through an in silico approach.

Adenovirus species B, C, D, and E are the most common causes of ocular manifestations caused by adenoviruses. FDA-approved treatment agents for adenovirus infections are not available. Cell-mediated immunity is the major protective mechanism versus human adenoviruses (HAdVs) infection and T cells specific for peptide epitopes from nonstructural proteins can prevent adenoviral dissemination. E1A CR2 region of HAdVs Epitopes predicted for reinforcing cytotoxic T lymphocytes (CTLs) in the EKC patients. Among human adenoviruses E1 protein, four distinct E1A regions had a significantly higher level of homology than the rest of E1A protein. E1A protein inhibits IFN signal transduction. Epitope-based vaccines are designed to have flexible and simple methods to synthesize a vaccine, using an adjuvant to trigger fast immune responses. CTL epitopes were applied to create a multiepitope vaccine. Conserve region1 (CR1) and CR3 have less antigenicity compared to CR2. Additionally, CR3 in HAdV-D8 contains three toxic areas. CR4 similar to the two regions CR1 and CR3 do not show acceptable antigenic properties. Bioinformatics' tools were used to predict, refine and validate the 3D structure of the construct. Effective binding was predicted by protein-protein docking of the epitope vaccine with MHC-I molecules and revealed the safety and efficacy of the predicted vaccine construct. In silico analysis show that rising levels of cytotoxic CD8 + T cells, TH1 cells, macrophages, and neutrophils are linked to IFN-dominant TH1-type responses, which are detected in putative immune individuals. Combined with 3D protein modeling, this study predicted the epitopes of E1A CR2 protein in HAdVs.

An Epidemic of Acute Hepatitis of Unknown Etiology in Children

An Epidemic of Acute Hepatitis of Unknown Etiology in Children

Filociclovir is a potent inhibitor of human adenovirus F41

Clusters of acute non HepA-E hepatitis cases in previously healthy children have been reported globally. At least, 1010 cases were identified in 35 countries, 5% of those cases required liver transplantation and 2% died. The exact cause is not yet known, but there is circumstantial evidence suggesting that human adenovirus F41 (HAdV-F41) might be playing a role. No antiviral drug has been approved for treating human adenovirus infections. Furthermore, HAdV-F41 is notoriously difficult to grow in cell culture, which hindered studying the efficacy of an antiviral compound against this virus. Here, we show that filociclovir (FCV), a nucleoside analog, is a potent inhibitor of HAdV-F41 in cell culture using 2 approaches, namely immunostaining of infected cells and virus yield reduction assay. The activity of FCV was compared to 3 other known antivirals: cidofovir (CDV), ganciclovir (GCV) and valganciclovir (VGCV). Among the 4 compounds examined in this study, FCV was the most potent, with an EC50 of 3.5 μM. These compounds can be ranked by potency as follows: FCV > CDV > GCV ≥ VGCV. In addition, FCV was 10-fold more potent than CDV in a virus yield reduction assay. This report provides timely and valuable methodologies to the research community for testing antivirals against HAdV-F41. Our findings also support the continued development of FCV for various therapeutic applications, including pediatric hepatitis, if a causal relationship is firmly established in the future.

Isolation and Genotyping of Adenoviruses from Wastewater and Diarrheal Samples in Egypt from 2016 to 2020.

Human adenoviruses (HAdV) are a prevalent cause of diarrhea in children all over the world. Adenoviral infections are responsible for 2% to 10% of diarrheic cases. A long-term investigation was required to gain better knowledge about the incidence of HAdV in Egypt. Herein, we conducted 5 years of detection, isolation, and genotyping of HAdV in fecal and sewage samples from 2016 to 2020, in Cairo, Egypt using molecular and cell culture assays. Human adenoviruses were identified in 35 of 447 fecal samples (7.8%), but only 53.3% (64/120) of the sewage samples. Children under the age of two had the highest positive rate for HAdV infection (77.1%). Species F of HAdV was the most common prevalent genotype in fecal and sewage samples, at 88.5% and 85.9%, respectively. The most prevalent genotypes detected in fecal samples were HAdV-41 (71.2%), HAdV-40 (17.2%), HAdV-6 (5.7%), and HAdV-1 (5.7%). In contrast, the most common genotypes in sewage samples were HAdV-41 (64%), HAdVs-40 (21.8%), HAdV-6 (7.8%), HAdV-1 (4.7%), and HAdV-2 (1.6%). HAdV was detected in all months of the year, with a peak period for clinical samples from December to February (p < 0.001), which matched Egypt’s rainy season, while the monthly distribution of HAdV in sewage samples remained consistent throughout the year, with no statistically significant peak period. Interestingly, the HAdV-type 41 genotype was the most common genotype during all of the years of this study. Throughout a 5-year period, our work revealed the infection rate, seasonal distribution, virus isolates, and genetic diversity of HAdV infections in environmental and clinical samples in Cairo, Egypt. Non-enteric adenovirus types (1, 2 and 6), as well as enteric adenovirus (41 and 40), may play a key role in gastroenteritis in Egypt.

A brief review on the molecular biology of human adenoviruses

Human adenoviruses infection causes diseases worldwide in all age groups and genders, which is associated with a wide range of diseases affecting the gastrointestinal tract, respiratory tract, urinary tract, and the eye, but they are often isolated from the pharynx and stool of asymptomatic children. However, in developing countries, diarrhea is a major cause of morbidity and mortality; and after rotaviruses, human adenoviruses are considered to be the second most important cause of viral infantile diarrhea. Also, human adenoviruses cause fatal acute respiratory distress syndrome in healthy adults and are especially fatal in infants and immune-compromised individuals. This review summarizes both classical and contemporary discoveries in the study of human adenoviruses at the molecular level, with particular emphasis on viral receptors, capsid proteins, nucleic acid, and genome properties as well as the molecular interactions governing the virion assembly. In this article, we provide insightful information concerning the molecular aspects of human adenoviruses. This would develop an understanding of the virus and serve as a powerful tool in identifying new approaches for the prevention and treatment of adenoviral infection.

Outpatient human coronavirus associated conjunctivitis in India.

BackgroundViral conjunctivitis (pink eye) can be highly contagious and is of public health importance. There remains significant debate whether SARS-CoV-2 can present as a primary conjunctivitis. The aim of this study was to identify pathogens associated with outpatient infectious conjunctivitis during the COVID-19 Delta surge.MethodsThis prospective study was conducted in the spring and summer months of 2021. 106 patients with acute conjunctivitis who presented to the Aravind Eye Center in Madurai, India were included. One anterior nasal swab and one conjunctival swab of each eye were obtained for each enrolled patient. Samples were subsequently processed for unbiased metagenomic RNA deep sequencing (RNA-seq). Outcomes included clinical findings and codetection of other pathogens with SARS-COV-2 in patients with conjunctivitis.ResultsAmong the 13 patients identified with human coronavirus RNA fragments in their swabs, 6 patients had SARS-COV-2 infection, 5 patients had coinfections of SARS-CoV-2 and human adenovirus (HAdV), 1 patient had a coinfection with human coronavirus OC43 and HAdV, and 1 patient had a coinfection of Vittaforma corneae and SARS-CoV-2. 30% had bilateral disease and symptoms on presentation. Petechial hemorrhage was noted in 33% of patients with SARS-COV-2 infection. No patients with SARS-CoV-2 or SARS-CoV-2 and HAdV infections had subepithelial infiltrates on presentation. All patients denied systemic symptoms.ConclusionsAmong the patients presented with conjunctivitis associated with human coronavirus infection, over 50% of the patients had co-infections with other circulating pathogens, suggesting the public-health importance of broad pathogen testing and surveillance in the outpatient conjunctivitis population.

Alterations in bile acids as metabolic signatures in the patients with human adenovirus type 7 infection.

ObjectivesThe changes in metabolism by human adenovirus (HAdV) infection was unclear. The potential mechanism of HAdV-7 causing acute respiratory tract infection was explored.MethodsTotally 35 patients with HAdV-7 infection, 32 asymptomatic cases with HAdV-7 and 14 healthy controls were enrolled from an outbreak of HAdV-7 in the army. The serum samples were analyzed by untargeted and targeted metabolomics. The effects of differential metabolites were verified on HAdV-7 replication in an A549 cell line.ResultsThe untargeted metabolomics analysis revealed more significant changes in the classes of sphingolipids, polyketides, glycerolipids, fatty acyls, and carboxylic acids and their derivatives in the patients with HAdV-7 than in healthy controls. Two key metabolic pathways of secondary and primary bile acid biosynthesis were noted from pathway enrichment analysis. Targeted metabolomics analysis showed that the levels of unconjugated bile acids in the patients were significantly lower, while the levels of glyco- and tauro- conjugated bile acids in patients and asymptomatic cases were higher than those in the healthy controls. The profiles of cytokines and peripheral lymphocyte subsets obviously varied at different levels of bile acids, with significant differences after HAdV-7 infection. A cell verification test demonstrated that the replication of HAdV-7 significantly reduced when GCDCA and TCA were added.ConclusionBile acids inhibited HAdV-7 replication in vitro. Alterations in bile acids was metabolic signatures of HAdV-7 infected subjects, and our results suggested bile acids might play protective roles against HAdV-7 infection.

Adenovirus Infection in Pediatric Hematopoietic Cell Transplantation: A Challenge Still Open for Survival.

Human Adenovirus (HAdV) infection occurs in 14–16% of patients in the early months after pediatric hematopoietic cell transplantation (HCT) and this correlates with a higher risk of developing HAdV disease and overall 6-month mortality. The main risk factors for HAdV infection are T-cell depletion of the graft by ex vivo CD34+ selection or in vivo use of alemtuzumab or anti-thymocyte serum, the development of grade III-IV graft versus host disease (GVHD), the type of donor (unrelated donor, cord blood, haploidentical, or HLA mismatched parent), and severe lymphopenia (<0.2 × 109/L). The prevention of HAdV disease is based on early intervention with antivirals in the asymptomatic patient when the permitted viral load threshold in the blood (≥102–3 copies/mL) and/or in the stool (109 copies/g stool) is exceeded. Cidofovir, a monophosphate nucleotide analog of cytosine, is the primary drug for preemptive therapy, used at 5 mg/kg/week for 2 weeks followed by 3–5 mg/kg every 2 weeks. The alternative schedule is 1 mg/kg every other day (three times/week). Enhancing virus-specific T-cell immunity in the first months post-HCT by donor-derived or third-party-derived virus-specific T cells represents an innovative and promising way of intervention, applicable both in prevention and therapeutic settings.

A Case Series of Children with Acute Hepatitis and Human Adenovirus Infection

BackgroundHuman adenoviruses typically cause self-limited respiratory, gastrointestinal, and conjunctival infections in healthy children. In late 2021 and early 2022, several previously healthy children were identified with acute hepatitis and human adenovirus viremia.MethodsWe used International Classification of Diseases, 10th Revision, codes to identify all children (<18 years of age) with hepatitis who were admitted to Children’s of Alabama hospital between October 1, 2021, and February 28, 2022; those with acute hepatitis who also tested positive for human adenovirus by whole-blood quantitative polymerase chain reaction (PCR) were included in our case series. Demographic, clinical, laboratory, and treatment data were obtained from medical records. Residual blood specimens were sent for diagnostic confirmation and human adenovirus typing.ResultsA total of 15 children were identified with acute hepatitis — 6 (40%) who had hepatitis with an identified cause and 9 (60%) who had hepatitis without a known cause. Eight (89%) of the patients with hepatitis of unknown cause tested positive for human adenovirus. These 8 patients plus 1 additional patient referred to this facility for follow-up were included in this case series (median age, 2 years 11 months; age range, 1 year 1 month to 6 years 5 months). Liver biopsies indicated mild-to-moderate active hepatitis in 6 children, some with and some without cholestasis, but did not show evidence of human adenovirus on immunohistochemical examination or electron microscopy. PCR testing of liver tissue for human adenovirus was positive in 3 children (50%). Sequencing of specimens from 5 children showed three distinct human adenovirus type 41 hexon variants. Two children underwent liver transplantation; all the others recovered with supportive care.ConclusionsHuman adenovirus viremia was present in the majority of children with acute hepatitis of unknown cause admitted to Children’s of Alabama from October 1, 2021, to February 28, 2022, but whether human adenovirus was causative remains unclear. Sequencing results suggest that if human adenovirus was causative, this was not an outbreak driven by a single strain. (Funded in part by the Centers for Disease Control and Prevention.)

Trained innate immunity and human adenovirus infection as a novel mechanism linked to the severe acute hepatitis of unknown origin in children during the COVID‐19 pandemic

Key points Recent clinical findings indicate that in severe acute hepatitis of unknown origin in children, the innate immune response underlies the main pathogenesis, regardless of the involved pathogens, including adenoviruses (AdVs) that predominantly affect the gut. The present work suggests that in the presence of trained immunity, the inflammation triggered by AdV infection is mild and confined to the gut, whereas without trained immunity, AdV infection can lead to viremia, severe inflammation, and even cytokine storms.

Non-hepatotropic viral hepatitis and its causative pathogens: The ongoing need for monitoring in children with severe acute hepatitis of unknown etiology.

Non-hepatotropic viral hepatitis and its causative pathogens: The ongoing need for monitoring in children with severe acute hepatitis of unknown etiology.