Outbreaks of different viral etiologies amidst COVID-19 pandemic

The COVID-19 pandemic has severely affected public health system and surveillance of other communicable diseases across the globe. The lockdown, travel constraints and COVID phobia turned down the number of people with illness visiting to the clinics or hospitals. Besides this, the heavy workload of SARS-CoV-2 diagnosis has led to the reduction in differential diagnosis of other diseases. Consequently, it added to the underlying burden of many diseases which remained under-diagnosed. Amidst the pandemic, the rise of emerging and re-emerging infectious diseases was observed worldwide and reported to the World Health Organization i.e., Crimean Congo Hemorrhagic Fever (2022, Iraq;2021 India), Nipah virus (2021, India), Zika virus (2021, India), and H5N1 influenza (2021, India), Monkeypox (2022, multicountry outbreak), Ebola virus disease (2022, DRC, Uganda;2021, DRC, Guinea;2020, DRC), Marburg (2022, Ghana;2021, Guinea), Yellow fever (2022, Uganda, Kenya, West and Central Africa;2021, Ghana, Venezuela, Nigeria;2020, Senegal, Guinea, Nigeria, Gabon;2020, Ethiopia, Sudan, Uganda), Dengue (2022, Nepal, Pakistan, Sao Tome, Temor-Leste;2021, Pakistan), Middle east respiratory syndrome coronavirus (2022, Oman, Qatar;2021, Saudi Arabia, UAE;2020, Saudi Arabia, UAE), Rift valley fever (2021, Kenya;2020, Mauritania), wild poliovirus type 1 (2022, Mozambique), Lassa fever (2022, Guinea, Togo, Nigeria;2020, Nigeria), Avian Influenza (H3N8) (2022, China), Avian Influenza (H5N1) (2022, USA), H10N3 influenza (2021, China), Hepatitis E virus (2022, Sudan), Measles (2022, Malawi, Afghanistan;2020, Burundi, Mexico), Mayaro virus disease (2020, French Guiana), Oropouche virus disease (2020, French Guiana). All these diseases were associated with high morbidity and burdened the public health system during the COVID-19 pandemic. During this critical public health menace, majority of the laboratory workforce was mobilized to the SARS-CoV-2 diagnosis. This has limited the surveillance efforts that likely led to under diagnosis and under-detection of many infectious pathogens. Lockdowns and travel limitations also put a hold on human and animal surveillance studies to assess the prevalence of these zoonotic viruses. In addition, lack of supplies and laboratory personnel and an overburdened workforce negatively impacted differential diagnosis of the diseases. This is especially critical given the common symptoms between COVID-19 and other pathogens causing respiratory illnesses. Additionally, the vaccination programs against various vaccine preventable diseases were also hampered which might have added to the disease burden. Despite these challenges, the world is better prepared to detect and respond to emerging/re-emerging pathogens. India now has more than 3000 COVID-19 diagnostic laboratories and an enhanced hospital infrastructure. In addition, mobile BSL-3 facilities are being validated for onsite sampling and testing in remote areas during outbreak situations and surveillance activities. This will undoubtedly be valuable as the COVID-19 pandemic evolves as well as during future outbreaks and epidemics. In conclusion, an increase in the emergence and re-emergence of viruses demonstrates that other infectious diseases have been neglected during the COVID-19 pandemic. Lessons learned from the infrastructure strengthening, collaborations with multiple stakeholders, increased laboratory and manufacturing capacity, large-scale COVID-19 surveillance, extensive network for laboratory diagnosis, and intervention strategies can be implemented to provide quick, concerted responses against the future threats associated with other zoonotic pathogens.

Severe Acute Hepatitis in Children

Viral infections affecting the liver had a serious impact on humanity, as they have led to significant morbidity and mortality in patients with acute and chronic infections. The discovery of the viral agents of severe acute hepatitis in children triggered interest of the scientific community to establish the pathogenesis and diagnostic techniques to identify the affected population. But, WHO, together with scientists in various affected countries, are working to understand the cause of this infection that does not appear to belong to any of the known five types of hepatitis viruses: A, B, C, D and E. Many cases of severe acute hepatitis of unknown origin in children <10 years of age were reported by the International Health Regulations (IHR) was mainly by adenovirus infection, HAdV-41. Although most acute infections cause mild disease and even go undetected, some can lead to complications and turn fatal. With the rapid scientific and technological advances in the last centuries, controlling and even curing the infections became a possibility, with a large focus on preventive medicine through vaccination. The review article describes the epidemiology, pathogenesis, clinical presentation, diagnostic tools and current medication regimens for severe acute hepatitis of unknown origin in children.Copyright © 2022, Global Research Online. All rights reserved.

Low Prevalence of HEV Infection and No Associated Risk of HEV Transmission from Mother to Child among Pregnant Women in Vietnam.

Infections with HEV in low- and middle-income countries (LMICs) are associated with increased rates of preterm birth, miscarriage, and stillbirth. The aim of the present study was to investigate HEV infections in pregnant women and the possibility of mother-to-child transmission, and associated outcomes. A total of 183 pregnant women in their third trimester were recruited and followed until delivery. Anti-HEV IgG and IgM were determined via enzyme-linked immunosorbent assay (ELISA), and HEV nucleic acids were detected in stool and cord blood samples. HEV genotypes were identified by Sanger sequencing, and phylogenetic analyses were performed. Mother-to-child transmission and associated adverse outcomes were not observed. Only 2% of patients (n = 4/183) tested positive for anti-HEV IgM, and 8% (n = 14/183) tested positive for anti-HEV IgG antibodies. Cord blood (n = 150) analysis showed that there was no IgM detected, while 4% (n = 6/150) tested positive for anti-HEV IgG, which was consistent with mothers testing positive for anti-HEV IgG. Nucleic acid tests for HEV RNA yielded 2% (n = 4/183) from the serum and stool of pregnant women, and none from cord blood. The HEV isolates belonged to the genotype HEV-3a, with 99% homology with humans and 96% with pigs. No association was found between the risk of HEV infection and pregnancy outcomes or HEV transmission from mother to child. HEV-3 infections of zoonotic origin in pregnancy might have eventually resolved without complications.

CdSe-Co3O4@TiO2 nanoflower-based photoelectrochemical platform probing visible light-driven virus detection.

The design and construction of a visible light-driven photoelectrochemical (PEC) device is described based on a CdSe-Co3O4@TiO2 nanoflower (NF). Moreover, an application to the ultrasensitive detection of viruses, such as hepatitis E virus (HEV), HEV-like particles (HEV-LPs), and SARS-CoV-2 spike protein in complicated lysate solution, is demonstrated. The photocurrent response output of a PEC device based on CdSe-Co3O4@TiO2 is enhanced compared with the individual components, TiO2 and CdSe-Co3O4. This can be attributed to the CdSe quantum dot (QD) sensitization effect and strong visible light absorption to improve overall system stability. A robust oxygen-evolving catalyst (Co3O4) coupled at the hole-trapping site (CdSe) extends the interfacial carrier lifetime, and the energy conversion efficiency was improved. The effective hybridization between the antibody and virus resulted in a linear relationship between the change in photocurrent density and the HEV-LP concentration ranging from 10 fg mL-1 to 10 ng mL-1, with a detection limit of 3.5 fg mL-1. This CdSe-Co3O4@TiO2-based PEC device achieved considerable sensitivity, good specificity, and acceptable stability and demonstrated a significant ability to develop an upgraded device with affordable and portable biosensing capabilities.

Integrative Multiomics and Regulatory Network Analyses Uncovers the Role of OAS3, TRAFD1, miR-222-3p, and miR-125b-5p in Hepatitis E Virus Infection.

The hepatitis E virus (HEV) is a long-ignored virus that has spread globally with time. It ranked 6th among the top risk-ranking viruses with high zoonotic spillover potential; thus, considering its viral threats is a pressing priority. The molecular pathophysiology of HEV infection or the underlying cause is limited. Therefore, we incorporated an unbiased, systematic methodology to get insights into the biological heterogeneity associated with the HEV. Our study fetched 93 and 2016 differentially expressed genes (DEGs) from chronic HEV (CHEV) infection in kidney-transplant patients, followed by hub module selection from a weighted gene co-expression network (WGCN). Most of the hub genes identified in this study were associated with interferon (IFN) signaling pathways. Amongst the genes induced by IFNs, the 2'-5'-oligoadenylate synthase 3 (OAS3) protein was upregulated. Protein-protein interaction (PPI) modular, functional enrichment, and feed-forward loop (FFL) analyses led to the identification of two key miRNAs, i.e., miR-222-3p and miR-125b-5p, which showed a strong association with the OAS3 gene and TRAF-type zinc finger domain containing 1 (TRAFD1) transcription factor (TF) based on essential centrality measures. Further experimental studies are required to substantiate the significance of these FFL-associated genes and miRNAs with their respective functions in CHEV. To our knowledge, it is the first time that miR-222-3p has been described as a reference miRNA for use in CHEV sample analyses. In conclusion, our study has enlightened a few budding targets of HEV, which might help us understand the cellular and molecular pathways dysregulated in HEV through various factors. Thus, providing a novel insight into its pathophysiology and progression dynamics.

High-Yield Production of Chimeric Hepatitis E Virus-Like Particles Bearing the M2e Influenza Epitope and Receptor Binding Domain of SARS-CoV-2 in Plants Using Viral Vectors.

Capsid protein of Hepatitis E virus (HEV) is capable of self-assembly into virus-like particles (VLPs) when expressed in Nicotiana benthamiana plants. Such VLPs could be used as carriers of antigens for vaccine development. In this study, we obtained VLPs based on truncated coat protein of HEV bearing the M2e peptide of Influenza A virus or receptor-binding domain of SARS-CoV-2 spike glycoprotein (RBD). We optimized the immunogenic epitopes' presentation by inserting them into the protruding domain of HEV ORF2 at position Tyr485. The fusion proteins were expressed in Nicotiana benthamiana plants using self-replicating potato virus X (PVX)-based vector. The fusion protein HEV/M2, targeted to the cytosol, was expressed at the level of about 300-400 µg per gram of fresh leaf tissue and appeared to be soluble. The fusion protein was purified using metal affinity chromatography under native conditions with the final yield about 200 µg per gram of fresh leaf tissue. The fusion protein HEV/RBD, targeted to the endoplasmic reticulum, was expressed at about 80-100 µg per gram of fresh leaf tissue; the yield after purification was up to 20 µg per gram of fresh leaf tissue. The recombinant proteins HEV/M2 and HEV/RBD formed nanosized virus-like particles that could be recognized by antibodies against inserted epitopes. The ELISA assay showed that antibodies of COVID-19 patients can bind plant-produced HEV/RBD virus-like particles. This study shows that HEV capsid protein is a promising carrier for presentation of foreign antigen.

Expression and Immunogenicity of SARS-CoV-2 Virus-Like Particles based on Recombinant Truncated HEV-3 ORF2 Capsid Protein.

COVID-19 is an emerging disease that poses a severe threat to global public health. As such, there is an urgent demand for vaccines against SARS-CoV-2, the virus that causes COVID-19. Here, we describe a virus-like nanoparticle candidate vaccine against SARS-CoV-2 produced by an E. coli expression system. The fusion protein of a truncated ORF2-encoded protein of aa 439~608 (p170) from hepatitis E virus CCJD-517 and the receptor-binding domain of the spike protein from SARS-CoV-2 were expressed, purified and characterized. The antigenicity and immunogenicity of p170-RBD were evaluated in vitro and in Kunming mice. Our investigation revealed that p170-RBD self-assembled into approximately 24 nm virus-like particles, which could bind to serum from vaccinated people (p < 0.001) and receptors on cells. Immunization with p170-RBD induced the titer of IgG antibody vaccine increased from 14 days post-immunization and was significantly enhanced after a booster immunization at 28 dpi, ultimately reaching a peak level on 42 dpi with a titer of 4.97 log10. Pseudovirus neutralization tests showed that the candidate vaccine induced a strong neutralizing antibody response in mice. In this research, we demonstrated that p170-RBD possesses strong antigenicity and immunogenicity and could be a potential candidate for use in future SARS-CoV-2 vaccine development.

Investigation of coronavirus and hepatitis E virus in rodents in Dali City, Yunnan Province

An investigation of coronavirus (CoV) and hepatitis E virus (HEV) in rodents was performed to understand CoV and HEV infection of rodents in Dali City, Yunnan Province. Rodent samples were obtained in the four towns of Dali city through traps from August 2020 to August 2021. A total of 76 rodents belonging to six species and five genera were captured: Rattus tanezumi, Rattus norvegicus, Apodemus chevrieri, Eothenomys miletus, Niviventer fulvescens, and Mus Pahari. Detection of CoV and HEV was performed by nested-PCR. The infection rate of CoV was 40.74% (11/27) and 2.38% (1/42) in R. norvegicus and R. tanezumi, respectively. The infection rate of HEV was 14.81% (4/27) and 2.38% (1/42) in R. norvegicus and R. tanezumi, respectively. Co-infection with CoV and HEV was detected in two R. norvegicus, with a co-infection rate of 7.41% (2/27). A Basic Local Alignment Search Tool (BLAST) search was performed on partial RNA-dependent RNA polymerase (RdRp) sequences of CoV and HEV. Eleven strains from R. norvegicus were a-CoV, and matched best to strain KY370050 from Rattus losea (Fujian, China), with 99.73% to 99.74% nucleotide (nt) sequency identity. One strain was ss-CoV from R. tanezumi, which displayed 98.21% nt sequence identity with strain MT820632 from Bandicota indica (Yunnan, China). Five strains from R. norvegicus were all HEV-C, and showed 95.87% to 96.21% sequence similarity to strain MN450853 from a patient in Hong Kong, China. In conclusion, CoV and HEV infections are present in rodents in Dali City. Because the host animals of the two viruses are closely related to humans, surveillance and investigations of related viruses should be strengthened.

Plant-Derived Recombinant Vaccines against Zoonotic Viruses.

Emerging and re-emerging zoonotic diseases cause serious illness with billions of cases, and millions of deaths. The most effective way to restrict the spread of zoonotic viruses among humans and animals and prevent disease is vaccination. Recombinant proteins produced in plants offer an alternative approach for the development of safe, effective, inexpensive candidate vaccines. Current strategies are focused on the production of highly immunogenic structural proteins, which mimic the organizations of the native virion but lack the viral genetic material. These include chimeric viral peptides, subunit virus proteins, and virus-like particles (VLPs). The latter, with their ability to self-assemble and thus resemble the form of virus particles, are gaining traction among plant-based candidate vaccines against many infectious diseases. In this review, we summarized the main zoonotic diseases and followed the progress in using plant expression systems for the production of recombinant proteins and VLPs used in the development of plant-based vaccines against zoonotic viruses.

Advances in acute severe hepatitis of unknown etiology in children

Since the International Health Regulations National Focal Point for the United Kingdom alerted the WHO of ten cases of acute severe hepatitis of unknown etiology in children on April 5, 2022, relevant cases have been reported worldwide. These patients had acute hepatitis (negative for hepatitis viruses A-E) and elevated aminotransferase (AST) or alanine aminase (ALT) exceeding 500 U/L. Furthermore, severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and/or adenovirus type F41 have been detected in some cases. This unknown hepatitis has been hypothesized to be induced by a viral reservoir of novel coronavirus superantigen, which repeatedly stimulates the intestines and leads to a multisystem inflammatory syndrome in children (MIS-C), which causes immune abnormalities in the presence of human adenovirus. Although this hypothesis has not been confirmed by any in vivo experimental or clinical studies, it may provide ideas for possible intervention strategies.

Research status and trend of zoonosis and zoonotic microorganisms based on pubmed database retrieval

Objective: To gather information on the research status and the hot spots of zoonosis and zoonotic microorganisms worldwide, and to provide references for the prevention and control of zoonotic diseases in China. Method: COOC 12.6 and Citespace 5.8 R1 software were used to carry out frequency statistics, co-occurrence analysis, cluster analysis, timeline analysis and burst analysis on the keywords associated with zoonosis and zoonotic microorganisms in PubMed database. Result: According to the keywords frequency statistics and co-occurrence analysis results from the year of 2001 to 2021 in pubMed database, the zoonosis and zoonotic microorganisms arousing high international attentions were classified into the following three categories: the first category was commonly observed zoonotic microorganisms such as Brucella, hepatitis E virus, Streptococcus, Escherichia coli (E. coli) and Salmonella, to which continuous public attentions were still needed to be paid;the second category was the zoonotic microorganisms worldwide concerned in recent years such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and influenza A virus, which were worthy of more in-depth research to control the spread of these diseases as soon as possible;the third category was the zoonosis that had massively prevailed in specific regions abroad such as Q fever and middle east respiratory syndrome (MERS), and these diseases were expected to be noticed in terms of imported risks to avoid their outbreaks in China. In addition to the above mentioned zoonosis and zoonotic microorganisms, some keywords associated with detection and diagnosis such as phylogeny and PCR were also of high interests. The cluster analysis generated a total of 10 clusters, in which the tick-borne infectious disease cluster suggested the role of ticks in the transmission of zoonotic diseases;the results of timeline and burst analysis demonstrated that among the zoonotic microorganisms, the attentions being paid to influenza A virus and SARS-CoV-2 were gradually increasing. At the same time, the detection technology of zoonotic microorganisms was evolving from specific sequence detection to whole genome sequencing. These fields were likely to be the research direction and trend in the future.

Ecological Barrier Deterioration Driven by Human Activities Poses Fatal Threats to Public Health due to Emerging Infectious Diseases

The coronavirus disease 2019 (COVID-19) and concerns about several other pandemics in the 21st century have attracted extensive global attention. These emerging infectious diseases threaten global public health and raise urgent studies on unraveling the underlying mechanisms of their transmission from animals to humans. Although numerous works have intensively discussed the cross-species and endemic barriers to the occurrence and spread of emerging infectious diseases, both types of barriers play synergistic roles in wildlife habitats. Thus far, there is still a lack of a complete understanding of viral diffusion, migration, and transmission in ecosystems from a macro perspective. In this review, we conceptualize the ecological barrier that represents the combined effects of cross-species and endemic barriers for either the natural or intermediate hosts of viruses. We comprehensively discuss the key influential factors affecting the ecological barrier against viral transmission from virus hosts in their natural habitats into human society, including transmission routes, contact probability, contact frequency, and viral characteristics. Considering the significant impacts of human activities and global industrialization on the strength of the ecological barrier, ecological barrier deterioration driven by human activities is critically analyzed for potential mechanisms. Global climate change can trigger and expand the range of emerging infectious diseases, and human disturbances promote higher contact frequency and greater transmission possibility. In addition, globalization drives more transmission routes and produces new high-risk regions in city areas. This review aims to provide a new concept for and comprehensive evidence of the ecological barrier blocking the transmission and spread of emerging infectious diseases. It also offers new insights into potential strategies to protect the ecological barrier and reduce the wide-ranging risks of emerging infectious diseases to public health. (c) 2020 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Chirohepevirus from Bats: Insights into Hepatitis E Virus Diversity and Evolution

Homologs of the human hepatitis E virus (HEV) have been identified in more than a dozen animal species. Some of them have been evidenced to cross species barriers and infect humans. Zoonotic HEV infections cause chronic liver diseases as well as a broad range of extrahepatic manifestations, which increasingly become significant clinical problems. Bats comprise approximately one-fifth of all named mammal species and are unique in their distinct immune response to viral infection. Most importantly, they are natural reservoirs of several highly pathogenic viruses, which have induced severe human diseases. Since the first discovery of HEV-related viruses in bats in 2012, multiple genetically divergent HEV variants have been reported in a total of 12 bat species over the last decade, which markedly expanded the host range of the HEV family and shed light on the evolutionary origin of human HEV. Meanwhile, bat-borne HEV also raised critical public health concerns about its zoonotic potential. Bat HEV strains resemble genomic features but exhibit considerable heterogeneity. Due to the close evolutionary relationships, bat HEV altogether has been recently assigned to an independent genus, Chirohepevirus. This review focuses on the current state of bat HEV and provides novel insights into HEV genetic diversity and molecular evolution.

The Human Liver-Expressed Lectin CD302 Restricts Hepatitis C Virus Infection.

C-type lectin domain-containing proteins (CTLDcps) shape host responses to pathogens and infectious disease outcomes. Previously, we identified the murine CTLDcp Cd302 as restriction factor, limiting hepatitis C virus (HCV) infection of murine hepatocytes. In this study, we investigated in detail the human orthologue's ability to restrict HCV infection in human liver cells. CD302 overexpression in Huh-7.5 cells potently inhibited infection of diverse HCV chimeras representing seven genotypes. Transcriptional profiling revealed abundant CD302 mRNA expression in human hepatocytes, the natural cellular target of HCV. Knockdown of endogenously expressed CD302 modestly enhanced HCV infection of Huh-7.5 cells and primary human hepatocytes. Functional analysis of naturally occurring CD302 transcript variants and engineered CD302 mutants showed that the C-type lectin-like domain (CTLD) is essential for HCV restriction, whereas the cytoplasmic domain (CPD) is dispensable. Coding single nucleotide polymorphisms occurring in human populations and mapping to different domains of CD302 did not influence the capacity of CD302 to restrict HCV. Assessment of the anti-HCV phenotype at different life cycle stages indicated that CD302 preferentially targets the viral entry step. In contrast to the murine orthologue, overexpression of human CD302 did not modulate downstream expression of nuclear receptor-controlled genes. Ectopic CD302 expression restricted infection of liver tropic hepatitis E virus (HEV), while it did not affect infection rates of two respiratory viruses, including respiratory syncytial virus (RSV) and the alpha coronavirus HVCoV-229E. Together, these findings suggest that CD302 contributes to liver cell-intrinsic defense against HCV and might mediate broader antiviral defenses against additional hepatotropic viruses. IMPORTANCE The liver represents an immunoprivileged organ characterized by enhanced resistance to immune responses. However, the importance of liver cell-endogenous, noncytolytic innate immune responses in pathogen control is not well defined. Although the role of myeloid cell-expressed CTLDcps in host responses to viruses has been characterized in detail, we have little information about their potential functions in the liver and their relevance for immune responses in this organ. Human hepatocytes endogenously express the CTLDcp CD302. Here, we provide evidence that CD302 limits HCV infection of human liver cells, likely by inhibiting a viral cell entry step. We confirm that the dominant liver-expressed transcript variant, as well as naturally occurring coding variants of CD302, maintain the capacity to restrict HCV. We further show that the CTLD of the protein is critical for the anti-HCV activity and that overexpressed CD302 limits HEV infection. Thus, CD302 likely contributes to human liver-intrinsic antiviral defenses.

Induction of Hepatitis E Virus Anti-ORF3 Antibodies from Systemic Administration of a Muscle-Specific Adeno-Associated Virus (AAV) Vector.

The hepatitis E virus (HEV) is a major global health problem, leading to large outbreaks in the developing world and chronic infections in the developed world. HEV is a non-enveloped virus, which circulates in the blood in a quasi-enveloped form. The quasi-envelope protects HEV particles from neutralising anti-capsid antibodies in the serum; however, most vaccine approaches are designed to induce an immune response against the HEV capsid. In this study, we explored systemic in vivo administration of a novel synthetic and myotropic Adeno-associated virus vector (AAVMYO3) to express the small HEV phosphoprotein ORF3 (found on quasi-enveloped HEV) in the musculature of mice, resulting in the robust and dose-dependent formation of anti-ORF3 antibodies. Neutralisation assays using the serum of ORF3 AAV-transduced mice showed a modest inhibitory effect on the infection of quasi-enveloped HEV in vivo, comparable to previously characterised anti-ORF3 antibodies used as a control. The novel AAVMYO3 capsid used in this study can serve as a versatile platform for the continued development of vector-based vaccines against HEV and other infectious agents, which could complement traditional vaccines akin to the current positive experience with SARS-CoV-2.

Is There A Correlation Between COVID-19 and Hepatitis A and Hepatitis E Serum Antibody Level?

BACKGROUND & OBJECTIVE: The prevalence of COVID-19 and its severity have been observed to be on a lower level in underdeveloped countries with poorer standards of hygiene. This disparity may be attributed to the higher seroprevalence of other viral diseases, which can result in the presence of antibodies protective against COVID-19. Two of the widespread diseases in such countries are infection to hepatitis A and E viruses (HAV and HEV). In the present study, we explored the relationship between the level of antibodies against these viruses and the susceptibility to COVID-19. METHODS: Ninety patients were studied in two groups of controls and cases, each consisting 45 individuals. The cases were patients with the clinical symptoms of COVID-19 and positive RT-PCR test results. The controls were individuals referred to the respiratory triage of Imam Khomeini Hospital Complex and were not demonstrating relevant clinical symptoms of COVID-19 and their RT-PCR test results were negative. Levels of HAV and HEV antibodies were measured and compared in these two groups. RESULTS: The median of HAV antibody level was 13.6 (IQR=11.5-16.9) and 13.2 (IQR =10.7-14.7) in cases and controls, respectively, showing no statistically significant difference (P=0.1). Likewise, the median of HEV antibody level was 6.7 (IQR=5.3-7.1) and 7.1 (IQR=6.3-7.5) in cases and controls, respectively, which again showed no statistically significant difference (P=0.41). CONCLUSION: The present study was carried out in a region with a relatively high prevalence of HAV and HEV infections. Contrary to our expectations, no statistically significant relationship was observed between the levels of antibodies against these viruses and the susceptibility to COVID-19. Further studies with larger sample sizes and in other countries are needed to come to a definite conclusion.

Hepatitis E in Bangladesh: Insights From a National Serosurvey.

BACKGROUND: Hepatitis E virus (HEV) genotypes 1 and 2 are a major cause of avoidable morbidity and mortality in South Asia. Despite the high risk of death among infected pregnant women, scarce incidence data has been a contributing factor to global policy recommendations against the introduction of licensed hepatitis E vaccines, one of the only effective prevention tools. METHODS: We tested serum from a nationally representative serosurvey in Bangladesh for anti-HEV immunoglobulin G and estimated seroprevalence. We used Bayesian geostatistical models to generate high-resolution maps of seropositivity and examined variability in seropositivity by individual-level, household-level, and community-level risk factors using spatial logistic regression. RESULTS: We tested serum samples from 2924 individuals from 70 communities representing all divisions of Bangladesh and estimated a national seroprevalence of 20% (95% confidence interval [CI], 17%-24%). Seropositivity increased with age and male sex (odds ratio, 2.2 male vs female; 95% CI, 1.8-2.8). Community-level seroprevalence ranged widely (0-78%) with higher seroprevalence in urban areas, including Dhaka, with a 3.0-fold (95% credible interval, 2.3-3.7) higher seroprevalence than the rest of the country. CONCLUSIONS: Hepatitis E infections are common throughout Bangladesh. Strengthening surveillance for hepatitis E, especially in urban areas, can provide additional evidence to appropriately target interventions.