Human coronavirus and acute respiratory illness in older adults with chronic obstructive pulmonary disease

Seasonal human coronavirus humoral responses in AZD1222 (ChaAdOx1 nCoV-19) COVID-19 vaccinated adults reveal limited cross-immunity

Background

Immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now widespread; however, the degree of cross-immunity between SARS-CoV-2 and endemic, seasonal human coronaviruses (HCoVs) remains unclear.

Methods

SARS-CoV-2 and HCoV cross-immunity was evaluated in adult participants enrolled in a US sub-study in the phase III, randomized controlled trial (NCT04516746) of AZD1222 (ChAdOx1 nCoV-19) primary-series vaccination for one-year. Anti-HCoV spike-binding antibodies against HCoV-229E, HCoV-HKU1, HCoV-OC43, and HCoV-NL63 were evaluated in participants following study dosing and, in the AZD1222 group, after a non-study third-dose booster. Timing of SARS-CoV-2 seroconversion (assessed via anti-nucleocapsid antibody levels) and incidence of COVID-19 were evaluated in those who received AZD1222 primary-series by baseline anti-HCoV titers.

Results

We evaluated 2,020/21,634 participants in the AZD1222 group and 1,007/10,816 in the placebo group. At the one-year data cutoff (March 11, 2022) mean duration of follow up was 230.9 (SD: 106.36, range: 1-325) and 94.3 (74.12, 1-321) days for participants in the AZD1222 (n = 1,940) and placebo (n = 962) groups, respectively. We observed little elevation in anti-HCoV humoral titers post study-dosing or post-boosting, nor evidence of waning over time. The occurrence and timing of SARS-CoV-2 seroconversion and incidence of COVID-19 were not largely impacted by baseline anti-HCoV titers.

Conclusion

We found limited evidence for cross-immunity between SARS-CoV-2 and HCoVs following AZD1222 primary series and booster vaccination. Susceptibility to future emergence of novel coronaviruses will likely persist despite a high prevalence of SARS-CoV-2 immunity in global populations.

Ontology-based taxonomical analysis of experimentally verified natural and laboratory human coronavirus hosts and its implication for COVID-19 virus origination and transmission

To fully understand COVID-19, it is critical to study all possible hosts of SARS-CoV-2 (the pathogen of COVID-19). In this work, we collected, annotated, and performed ontology-based taxonomical analysis of all the reported and verified hosts for all human coronaviruses including SARS-CoV, MERS-CoV, SARS-CoV-2, HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1. A total of 37 natural hosts and 19 laboratory animal hosts of human coronaviruses were identified based on experimental evidence. Our analysis found that all the verified susceptible natural and laboratory animals belong to therian mammals. Specifically, these 37 natural therian hosts include one wildlife marsupial mammal (i.e., Virginia opossum) and 36 Eutheria mammals (a.k.a. placental mammals). The 19 laboratory animal hosts are also classified as therian mammals. The mouse models with genetically modified human ACE2 or DPP4 were more susceptible to virulent human coronaviruses with clear symptoms, suggesting the critical role of ACE2 and DPP4 to coronavirus virulence. Coronaviruses became more virulent and adaptive in the mouse hosts after a series of viral passages in the mice, providing clue to the possible coronavirus origination. The Huanan Seafood Wholesale Market animals identified early in the COVID-19 outbreak were also systematically analyzed as possible COVID-19 hosts. To support knowledge standardization and query, the annotated host knowledge was modeled and represented in the Coronavirus Infectious Disease Ontology (CIDO). Based on our and others' findings, we further propose a MOVIE model (i.e., Multiple-Organism viral Variations and Immune Evasion) to address how viral variations in therian animal hosts and the host immune evasion might have led to dynamic COVID-19 pandemic outcomes.

Improved Culture Methods for Human Coronaviruses HCoV-OC43, HCoV-229E, and HCoV-NL63

HCoV-OC43, HCoV-229E, HCoV-NL63, and HCoV-HKU1 are four of the seven known human coronaviruses (HCoVs) and, unlike the highly pathogenic SARS-CoV, MERS-CoV, and SARS-CoV-2, these four so-called seasonal HCoVs generally cause mild upper-respiratory-tract illness. As Biosafety Level 2 (BSL-2) pathogens, the seasonal HCoVs are more accessible and can be used as surrogates for studying the highly pathogenic HCoVs. However, scientists have for many years found these difficult to study because of the lack of a universal culture system and the inability of typical culture methods to yield high-titer infectious stocks. We have developed assays to grow and quantify infectious virus and viral RNA for HCoV-OC43, -229E, and -NL63. We identified which immortalized cell lines should be used to optimize the replication of HCoV-OC43, -229E, and -NL63 in order to generate high titers (Vero E6, Huh-7, and LLC-MK2 cells, respectively). Here we present protocols for improved propagation and quantification of each seasonal HCoV. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Growth of HCoVs Basic Protocol 2: Quantification of HCoV by plaque assay Basic Protocol 3: Quantification of HCoV RNA products of replication Basic Protocol 4: Concentrating HCoVs via ultracentrifugation.

The FDA-approved drug nitazoxanide is a potent inhibitor of human seasonal coronaviruses acting at postentry level: effect on the viral spike glycoprotein

Coronaviridae is recognized as one of the most rapidly evolving virus family as a consequence of the high genomic nucleotide substitution rates and recombination. The family comprises a large number of enveloped, positive-sense single-stranded RNA viruses, causing an array of diseases of varying severity in animals and humans. To date, seven human coronaviruses (HCoV) have been identified, namely HCoV-229E, HCoV-NL63, HCoV-OC43 and HCoV-HKU1, which are globally circulating in the human population (seasonal HCoV, sHCoV), and the highly pathogenic SARS-CoV, MERS-CoV and SARS-CoV-2. Seasonal HCoV are estimated to contribute to 15-30% of common cold cases in humans; although diseases are generally self-limiting, sHCoV can sometimes cause severe lower respiratory infections and life-threatening diseases in a subset of patients. No specific treatment is presently available for sHCoV infections. Herein we show that the anti-infective drug nitazoxanide has a potent antiviral activity against three human endemic coronaviruses, the Alpha-coronaviruses HCoV-229E and HCoV-NL63, and the Beta-coronavirus HCoV-OC43 in cell culture with IC50 ranging between 0.05 and 0.15 μg/mL and high selectivity indexes. We found that nitazoxanide does not affect HCoV adsorption, entry or uncoating, but acts at postentry level and interferes with the spike glycoprotein maturation, hampering its terminal glycosylation at an endoglycosidase H-sensitive stage. Altogether the results indicate that nitazoxanide, due to its broad-spectrum anti-coronavirus activity, may represent a readily available useful tool in the treatment of seasonal coronavirus infections.

The Complex Association between COPD and COVID-19

Chronic obstructive pulmonary disease (COPD) is significant cause of morbidity and mortality worldwide. There is mounting evidence suggesting that COPD patients are at increased risk of severe COVID-19 outcomes; however, it remains unclear whether they are more susceptible to acquiring SARS-CoV-2 infection. In this comprehensive review, we aim to provide an up-to-date perspective of the intricate relationship between COPD and COVID-19. We conducted a thorough review of the literature to examine the evidence regarding the susceptibility of COPD patients to COVID-19 infection and the severity of their disease outcomes. While most studies have found that pre-existing COPD is associated with worse COVID-19 outcomes, some have yielded conflicting results. We also discuss confounding factors such as cigarette smoking, inhaled corticosteroids, and socioeconomic and genetic factors that may influence this association. Furthermore, we review acute COVID-19 management, treatment, rehabilitation, and recovery in COPD patients and how public health measures impact their care. In conclusion, while the association between COPD and COVID-19 is complex and requires further investigation, this review highlights the need for careful management of COPD patients during the pandemic to minimize the risk of severe COVID-19 outcomes.

Impact of MERS-CoV and SARS-CoV-2 Viral Infection on Immunoglobulin-IgG Cross-Reactivity

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has posed a considerable threat to public health and global economies. SARS-CoV-2 has largely affected a vast world population and was declared a COVID-19 pandemic outbreak, with a substantial surge of SARS-CoV-2 infection affecting all aspects of the virus’ natural course of infection and immunity. The cross-reactivity between the different coronaviruses is still a knowledge gap in the understanding of the SARS-CoV-2 virus. This study aimed to investigate the impact of MERS-CoV and SARS-CoV-2 viral infections on immunoglobulin-IgG cross-reactivity. Our retrospective cohort study hypothesized the possible reactivation of immunity in individuals with a history of infection to Middle East Respiratory Syndrome coronavirus (MERS-CoV) when infected with SARS-CoV-2. The total number of participants included was 34; among them, 22 (64.7%) were males, and 12 (35.29%) were females. The mean age of the participants was 40.3 ± 12.9 years. This study compared immunoglobulin (IgG) levels against SARS-CoV-2 and MERS-CoV across various groups with various histories of infection. The results showed that a reactive borderline IgG against both MERS-CoV and SARS-CoV-2 in participants with past infection to both viruses was 40% compared with 37.5% among those with past infection with MERS-CoV alone. Our study results establish that individuals infected with both SARS-CoV-2 and MERS-CoV showed higher MERS-CoV IgG levels compared with those of individuals infected previously with MERS-CoV alone and compared with those of individuals in the control. The results further highlight cross-adaptive immunity between MERS-CoV and SARS-CoV. Our study concludes that individuals with previous infections with both MERS-CoV and SARS-CoV-2 showed significantly higher MERS-CoV IgG levels compared with those of individuals infected only with MERS-CoV and compared with those of individuals in the control, suggesting cross-adaptive immunity between MERS-CoV and SARS-CoV.

Association between the Seroprevalence of Antibodies against Seasonal Alphacoronaviruses and SARS-CoV-2 Humoral Immune Response, COVID-19 Severity, and Influenza Vaccination

The present study assesses the seroprevalence of antibodies against seasonal human alphacoronaviruses 229E and NL63 among adult patients infected with SARS-CoV-2, and its association with the humoral response to SARS-CoV-2 infection and its severity, and influenza vaccination. A serosurvey was conducted to quantify the presence of IgG antibodies against the nucleocapsid of 229E (anti-229E-N) and NL63 (anti-NL63-N), and anti-SARS-CoV-2 IgG antibodies (against nucleocapsid, receptor-binding domain, S2 domain, envelope, and papain-like protease) for 1313 Polish patients. The seroprevalence of anti-229E-N and anti-NL63 in the studied cohort was 3.3% and 2.4%. Seropositive individuals had a higher prevalence of anti-SARS-CoV-2 IgG antibodies, higher titers of the selected anti-SARS-CoV2 antibodies, and higher odds of an asymptomatic SARS-CoV-2 infection (OR = 2.5 for 229E and OR = 2.7 for NL63). Lastly, the individuals vaccinated against influenza in the 2019/2020 epidemic season had lower odds of seropositivity to 229E (OR = 0.38). The 229E and NL63 seroprevalence was below the expected pre-pandemic levels (up to 10%), likely due to social distancing, increased hygiene, and face masking. The study also suggests that exposure to seasonal alphacoronaviruses may improve humoral responses to SARS-CoV-2 while decreasing the clinical significance of its infection. It also adds to accumulating evidence of the favorable indirect effects of influenza vaccination. However, the findings of the present study are of a correlative nature and thereby do not necessarily imply causation.

Mouse models susceptible to HCoV-229E and HCoV-NL63 and cross protection from challenge with SARS-CoV-2

Human coronavirus 229E (HCoV-229E) and NL63 (HCoV-NL63) are endemic causes of upper respiratory infections such as the "common cold" but may occasionally cause severe lower respiratory tract disease in the elderly and immunocompromised patients. There are no approved antiviral drugs or vaccines for these common cold coronaviruses (CCCoV). The recent emergence of COVID-19 and the possible cross-reactive antibody and T cell responses between these CCCoV and SARS-CoV-2 emphasize the need to develop experimental animal models for CCCoV. Mice are an ideal experimental animal model for such studies, but are resistant to HCoV-229E and HCoV-NL63 infections. Here, we generated 229E and NL63 mouse models by exogenous delivery of their receptors, human hAPN and hACE2 using replication-deficient adenoviruses (Ad5-hAPN and Ad5-hACE2), respectively. Ad5-hAPN- and Ad5-hACE2-sensitized IFNAR^-/- and STAT1^-/- mice developed pneumonia characterized by inflammatory cell infiltration with virus clearance occurring 7 d post infection. Ad5-hAPN- and Ad5-hACE2-sensitized mice generated virus-specific T cells and neutralizing antibodies after 229E or NL63 infection, respectively. Remdesivir and a vaccine candidate targeting spike protein of 229E and NL63 accelerated viral clearance of virus in these mice. 229E- and NL63-infected mice were partially protected from SARS-CoV-2 infection, likely mediated by cross-reactive T cell responses. Ad5-hAPN- and Ad5-hACE2-transduced mice are useful for studying pathogenesis and immune responses induced by HCoV-229E and HCoV-NL63 infections and for validation of broadly protective vaccines, antibodies, and therapeutics against human respiratory coronaviruses including SARS-CoV-2.

An overview of gastrointestinal diseases in patients with COVID-19: A narrative review

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), has emerged as a global health concern. This study aimed to review the epidemiology and pathophysiology of COVID-19 and provide evidence for the implementation of control measures. We utilized several online databases, including MEDLINE (National Library of Medicine, Bethesda, Maryland, USA), PubMed, EMBASE, Web of Science, and Google Scholar, to collect relevant published papers using a combination of the following keywords: "COVID-19," "SARS-CoV-2," "novel coronavirus," "epidemiology," and "pathophysiology." The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used in this study. Globally, approximately 3-46% of patients with SARS-CoV-2 infection experience gastrointestinal symptoms. The clinical spectrum of COVID-19 is wide, ranging from mild to severe, and even fatal. COVID-19 was initially reported as a respiratory tract disease; however, gastrointestinal symptoms have only recently been reported. COVID-19 Patients with gastrointestinal symptoms may have more severe clinical manifestations and poor prognosis. This study highlights the need to better understand the mechanisms involved in the development of gastrointestinal symptoms in patients with COVID-19 to prevent the further spread of this pathogen.

A Proposal to Refer to Four Coronaviruses of Limited Human Virulence "Common Cold Coronaviruses"

We propose the term "common cold coronaviruses," or ccCoV, to describe the four human coronaviruses commonly associated with upper respiratory tract disease - coronaviruses 229E, OC43, NL63, and HKU1. This will differentiate these previously described coronaviruses from those causing more severe disease in humans - including the viruses severe acute respiraotry syndrome coronavirus (SARS-CoV), the Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2.

Review of selected animal models for respiratory coronavirus infection and its application in drug research

Numerous viral pneumonia cases have been reported in Wuhan, Hubei in December 2019. The pathogen has been identified as a novel coronavirus, which was named severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). The biological characteristics and pathogenesis mechanism of SARS‐CoV‐2 are unclear and under progress. At present, no specific preventive and therapeutic drugs are available. Animal models can reproduce the viral replication cycle and the significant functions of respiratory coronavirus infection and are urgently needed to evaluate the efficacy of drugs and vaccines, the transmission route of respiratory coronavirus, clinical features, and so on. We reviewed the current animal models of respiratory coronavirus (SARS‐CoV, MERS‐CoV, and SARS‐CoV‐2) infection and made a comparative analysis of the route of inoculation, virus replication, clinical signs, histopathology, application, advantages, and disadvantages. Animal models of respiratory coronavirus include susceptible animal models, genetically modified models, and various animal models of infected virus adaptation strains, such as nonhuman primates, mice, hamsters, ferrets, New Zealand rabbits, cats, and other animal models, all of which have distinct advantages and limitations. This review will provide relevant information and important insights for disease management and control.

Animal models for coronavirus infection.

Effect of Jinzhen granule on two coronaviruses: The novel SARS-CoV-2 and the HCoV-229E and the evidences for their mechanisms of action

BACKGROUND

Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human coronavirus 229E (HCoV-229E) pose a huge threat to human public health, no specific treatment is available. Jinzhen granule (JZ) is a traditional eight ingredients-Chinese medicine with prominent efficacy for treating viral-induced diseases. However, little is known about the antiviral effect and mechanism of JZ against SARS-CoV-2 and HCoV-229E.

PURPOSE

This study aimed to reveal the antiviral effects of JZ against SARS-CoV-2 and HCoV-229E, and to further explore the underlying mechanisms regulating the host immune response.

METHODS

The chromatographic separation of JZ was performed using a Shimadzu analytical high-performance liquid chromatograph with UV detection and Alltech ELSD 2000ES. We conducted cytopathic effect (CPE) and plaque reduction assays to evaluate the antiviral effect of JZ. A lethal human angiotensin converting enzyme 2 (hACE2) transgenic mouse model of SARS-CoV-2 was established to determine the protective effect of JZ on mortality and lung virus titers. Real-time quantitative PCR assays were used to analyze the expression of proinflammatory cytokines in vitro and in vivo. Western blotting was further performed to determine the activities on regulating the nuclear factor kappa B (NF-κB)/MAPK pathway. Finally, mitochondrial membrane potential assays, flow cytometry analysis and western blotting were used to assess the anti-apoptotic potency toward HCoV-229E infection.

RESULTS

The results showed that 13 chemical components were identified and five peaks were determined and quantitated (gallic acid 1.97 mg/g, baicalin 20.69 mg/g, glycyrrhizic acid 4.92 mg/g, hyodeoxycholic acid 4.86 mg/g, cholic acid 4.07 mg/g). We found that JZ exerted inhibitory potency against SARS-CoV-2 and HCoV-229E in vitro by using CPE and plaque reduction assays, and it was further found that JZ protected mice infected by SARS-CoV-2 from death and inhibited lung virus titers. JZ also significantly decreased the induction of inflammatory cytokines (IL-1α, IL-6, CCL-5 and MIP-1β), similar to the observed in vitro effect. Moreover, JZ suppressed the release of inflammatory cytokines in vitro and it decreased the protein expression of p-p38 MAPK, p-JNK, p-NF-κB p65 and p-IκBα induced by HCoV-229E and increased the expression of IκBα. Notably, JZ significantly protected HCoV-229E-infected Huh-7 cells from mitochondrial damage and decreased apoptotic cells. The activation of the mitochondria-mediated apoptotic pathway was inhibited by JZ, as shown by the reduced expression of cleaved caspase-9, caspase-3 and p-PARP.

CONCLUSIONS

In conclusion, JZ (gallic acid 1.97 mg/g, baicalin 20.69 mg/g, glycyrrhizic acid 4.92 mg/g, hyodeoxycholic acid 4.86 mg/g, cholic acid 4.07 mg/g) exhibited antiviral activities against SARS-CoV-2 and HCoV-229E by regulating the NF-κB/MAPK pathway and the mitochondria-mediated apoptotic pathway. These findings demonstrated the efficacy of JZ against CoVs and suggested JZ treatment as a novel clinical therapeutic strategy for COVID-19.

The therapeutic promises of Lianhuaqingke in the mice model of coronavirus pneumonia (HCoV-229E and SARS-CoV-2)

Background

Lianhuaqingke (LHQK) has been approved for the treatment of acute tracheobronchitis and exerts a broad-spectrum antiviral effect in our previous study.

Methods

Acute pneumonia caused by HCoV-229E was modeled in BALB/c mice. The anti-viral effect of LHQK was assessed by measuring the lung index and virus titer of lung tissues. The expression levels of pro-inflammatory cytokines in lung tissues and peripheral blood were measured by ELISA. The morphological changes of lung tissues were observed by H&E staining. The subsets of Th cells were assayed by the flow cytometry, including Th0, Th1, Th2, Treg, and Th17. The expression level of MUC5AC in 16HBE cells treated with TNFα was measured by ELISA. Immunofluorescence staining for β-IV tubulin was used to identify the airway epithelial ciliary in the condition-cultured RTE cells treated with TNFα. The direct antiviral effect of LHQK was assessed in vitro in Vero E6 infected by SARS-CoV-2, validated in vivo in the COVID-19 model of hACE2 transgenic mouse by detecting the lung index, the SARS-CoV-2 virus load, and the morphological changes of lung tissues.

Results

LHQK reduced the weight loss and the lung index by inhibiting the HCoV-229E replication and reducing the expression of pro-inflammatory cytokines in lung tissues. An assay for the Th cell subsets in peripheral blood revealed that LHQK could reduce the ratio of Th1/Th2 and increase the Treg/Th17 ratio in a dose-dependent way, which indicated that LHQK could coordinate the Th-mediated immune responses against the virus. In in vitro injury by TNFα, LHQK inhibited MUC5AC expression in 16HBE cells and increased the number of β-IV tubulin positive staining cells in the condition-cultured RTE cells. In the SARS-CoV-2-infected mice, LHQK could reduce weight loss, inhibit viral replication, and alleviate lung tissue damage.

Conclusions

Our results demonstrate that LHQK exerts therapeutic effects on pneumonia caused by HCoVs (HCoV-229E and SARS-CoV-2) in mice, and that the anti-HCoV effects might depend on its immunomodulatory capacities. All these results suggest that LHQK serves as a potential adjuvant for anti-HCoV therapies.

Neurological Implications of COVID-19: Role of Redox Imbalance and Mitochondrial Dysfunction

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2 or COVID-19 has been declared as a pandemic disease by the World Health Organization (WHO). Globally, this disease affected 159 million of the population and reported ~ 3.3 million deaths to the current date (May 2021). There is no definitive treatment strategy that has been identified, although this disease has prevailed in its current form for the past 18 months. The main challenges in the (SARS-CoV)-2 infections are in identifying the heterogeneity in viral strains and the plausible mechanisms of viral infection to human tissues. In parallel to the investigations into the patho-mechanism of SARS-CoV-2 infection, understanding the fundamental processes underlying the clinical manifestations of COVID-19 is very crucial for designing effective therapies. Since neurological symptoms are very apparent in COVID-19 infected patients, here, we tried to emphasize the involvement of redox imbalance and subsequent mitochondrial dysfunction in the progression of the COVID-19 infection. It has been articulated that mitochondrial dysfunction is very apparent and also interlinked to neurological symptoms in COVID-19 infection. Overall, this article provides an in-depth overview of redox imbalance and mitochondrial dysfunction involvement in aggravating COVID-19 infection and its probable contribution to the neurological manifestation of the disease.

Human Coronaviruses: Counteracting the Damage by Storm

Over the past 18 years, three highly pathogenic human (h) coronaviruses (CoVs) have caused severe outbreaks, the most recent causative agent, SARS-CoV-2, being the first to cause a pandemic. Although much progress has been made since the COVID-19 pandemic started, much about SARS-CoV-2 and its disease, COVID-19, is still poorly understood. The highly pathogenic hCoVs differ in some respects, but also share some similarities in clinical presentation, the risk factors associated with severe disease, and the characteristic immunopathology associated with the progression to severe disease. This review aims to highlight these overlapping aspects of the highly pathogenic hCoVs-SARS-CoV, MERS-CoV, and SARS-CoV-2-briefly discussing the importance of an appropriately regulated immune response; how the immune response to these highly pathogenic hCoVs might be dysregulated through interferon (IFN) inhibition, antibody-dependent enhancement (ADE), and long non-coding RNA (lncRNA); and how these could link to the ensuing cytokine storm. The treatment approaches to highly pathogenic hCoV infections are discussed and it is suggested that a greater focus be placed on T-cell vaccines that elicit a cell-mediated immune response, using rapamycin as a potential agent to improve vaccine responses in the elderly and obese, and the potential of stapled peptides as antiviral agents.

Naturally Occurring Bioactives as Antivirals: Emphasis on Coronavirus Infection

The current coronavirus disease (COVID-19) outbreak is a significant threat to human health and the worldwide economy. Coronaviruses cause a variety of diseases, such as pneumonia-like upper respiratory tract illnesses, gastroenteritis, encephalitis, multiple organ failure involving lungs and kidneys which might cause death. Since the pandemic started there have been more than 107 million COVID-19 infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and ∼2.4 million deaths globally. SARS-CoV-2 is easily transmitted from person-to-person and has spread quickly across all continents. With the continued increase in morbidity and mortality caused by COVID-19, and the damage to the global economy, there is an urgent need for effective prevention and treatment strategies. The advent of safe and effective vaccines has been a significant step forward in the battle against COVID-19, however treatment of the symptoms associated with the disease still requires new anti-viral and anti-inflammatory drug therapies. To this end, scientists have been investigating available natural products that may be effective against SARS-CoV-2, with some products showing promise in fighting several viral infections. Since many natural products are dietary components or are prepared as dietary supplements people tend to consider them safer than synthetic drugs. For example, Traditional Chinese Medicines have been effectively utilized to treat SARS-CoV-2 infected patients with promising results. In this review, we summarize the current knowledge of COVID-19 therapies and the therapeutic potential of medicinal plant extracts and natural compounds for the treatment of several viral infections, with special emphasis on SARS-CoV-2 infection. Realistic strategies that can be employed for the effective use of bioactive compounds for anti-SARS-CoV-2 research are also provided.

Seroprevalence of human coronaviruses among patients visiting hospital-based sentinel sites in Uganda

Background

Human coronaviruses are causative agents of respiratory infections with several subtypes being prevalent worldwide. They cause respiratory illnesses of varying severity and have been described to be continuously emerging but their prevalence is not well documented in Uganda. This study assessed the seroprevalence of antibodies against the previously known human coronaviruses prior 2019 in Uganda.

Methods

A total 377 serum samples collected from volunteers that showed influenza like illness in five hospital-based sentinel sites and archived were analyzed using a commercial Qualitative Human Coronavirus Antibody IgG ELISA kit. Although there is no single kit available that can detect the presence of all the circulating coronaviruses, this kit uses a nucleoprotein, aa 340–390 to coat the wells and since there is significant homology among the various human coronavirus strains with regards to the coded for proteins, there is significant cross reactivity beyond HCoV HKU-39849 2003. This gives the kit a qualitative ability to detect the presence of human coronavirus antibodies in a sample.

Results

The overall seroprevalence for all the sites was 87.53% with no significant difference in the seroprevalence between the Hospital based sentinel sites (p = 0.8). Of the seropositive, the age group 1–5 years had the highest percentage (46.97), followed by 6–10 years (16.67) and then above 20 (16.36). An odds ratio of 1.6 (CI 0.863–2.97, p = 0.136) showed that those volunteers below 5 years of age were more likely to be seropositive compared to those above 5 years. The seropositivity was generally high throughout the year with highest being recorded in March and the lowest in February and December.

Conclusions

The seroprevalence of Human coronaviruses is alarmingly high which calls for need to identify and characterize the circulating coronavirus strains so as to guide policy on the control strategies.

The contribution of veterinary public health to the management of the COVID-19 pandemic from a One Health perspective

The human coronavirus disease 2019 (COVID-19) pandemic represents one of the greatest public health crises in recent history, which has caused unprecedented and massive disruptions of social and economic life globally, and the biggest communication challenges for public information-sharing. While there is strong evidence that bats are the animal source of SARS-CoV-2, the causative agent of COVID-19, there are many uncertainties around the epidemiology, the intermediate animal species, and potential animal routes of SARS-Cov-2 transmission to humans. While it has also long been known that coronaviruses circulate among different animal species, including SARS-CoV and MERS-CoV, responsible for the pandemics of severe acute respiratory syndrome and Middle East respiratory syndrome endemic in Middle Eastern countries in 2002-2003 and 2012 respectively, the way this pandemic is being managed tends to downplay or neglect the veterinary contribution, which is not in line with the One Health approach, if we consider that the genesis of the COVID-19 pandemic, likewise SARS and MERS lies on a close and interdependent links of humans, animals and the environment. To overcome this flaw, and to better operationalize the One Health approach, there are several lines of contributions the veterinary profession might provide to manage the COVID-19 pandemic in the framework of interventions jointly concerted in the veterinary and medical domains, notably: the experience in dealing with past animal epidemics, the skills in conducting wildlife surveillance targeting emerging pathogens at risky hot spots, and with the aim to predict and prevent future pandemics, the laboratory support for the diagnosis and molecular characterization of SARS-CoV-2 and human samples testing, and animal import risk assessment to define COVID-19 risk strategy for international air travel. The veterinary profession presents itself ontologically with a strong One Health accent and all the related valuable knowledge can be properly integrated within centralised multidisciplinary task-forces set up at the national and international level, with a renewed role in the management and monitoring structures required for managing the COVID-19 pandemic.

Seasonal Human Coronavirus Respiratory Tract Infection in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

Background

Little is known about characteristics of seasonal human coronavirus (HCoV) (NL63, 229E, OC43 and HKU1) after allogeneic stem cell transplantation (allo-HCT).

Patients and methods

this is a collaborative Spanish and European bone marrow transplantation groups retrospective multicentre study, which included allo-HCT recipients (adults and children) with upper and/or lower respiratory tract disease (U/LRTD) caused by seasonal HCoV diagnosed through multiplex PCR assays from January 2012 to January 2019.

Results

We included 402 allo-HCT recipients who developed 449 HCoV U/LRTD episodes. Median age of recipients was 46 years (range 0.3-73.8 years). HCoV episodes were diagnosed at a median of 222 days after transplantation. The most common HCoV subtype was OC43 (n=170, 38%). LRTD involvement occurred in 121 episodes (27%). HCoV infection frequently required hospitalization (18%), oxygen administration (13%) and intensive care unit (ICU) admission (3%). Three-month overall mortality after HCoV detection was 7% in the whole cohort and 16% in those with LRTD. We identified 3 conditions associated with higher mortality in recipients with LRTD: absolute lymphocyte count <0.1 x10 ⁹/mL [hazard ratio (HR), 10.8], corticosteroid (HR 4.68) and ICU admission (HR 8.22) (p<0.01).

Conclusions

Seasonal HCoV after allo-HCT may involve the LRTD in many instances, leading to a significant morbidity.

First Detection of Human Coronavirus HKU1 in Greece, in an Immunocompromised Patient With Severe Lower Respiratory Tract Infection

Human coronavirus HKU1 (HCoV-HKU1) is a RNA virus which gets in the human cells by binding to the receptor of N-acetyl-9-O-acetylneuraminic acid. Human Coronaviruses (HCoVs), including HCoV-HKU1, are globally found. HCoV-HKU1 is responsible for upper and lower respiratory tract infections, usually with mild symptoms. In severe cases, HCoV-HKU1 can cause life-threatening respiratory illness especially in vulnerable hosts such as elderly, children and immunocompromised patients. In Greece, Respiratory Syncytial Virus (RSV) and influenza are the most common viruses causing respiratory tract infections. Traditionally, HCoVs are responsible for less than 3% of respiratory infections in Greek population. HCoVs 229E and OC43 have been shown to circulate in Greece. We report the first case of lung infection in an immunocompromised woman due to HCoV-HKU1, that has never been before detected in Greece. HCoV-HKU1 is related to severe disease even in healthy individuals and must be considered in the differential diagnosis of severe respiratory infections.

Network-based virus-host interaction prediction with application to SARS-CoV-2

COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has quickly become a global health crisis since the first report of infection in December of 2019. However, the infection spectrum of SARS-CoV-2 and its comprehensive protein-level interactions with hosts remain unclear. There is a massive amount of underutilized data and knowledge about RNA viruses highly relevant to SARS-CoV-2 and proteins of their hosts. More in-depth and more comprehensive analyses of that knowledge and data can shed new light on the molecular mechanisms underlying the COVID-19 pandemic and reveal potential risks. In this work, we constructed a multi-layer virus-host interaction network to incorporate these data and knowledge. We developed a machine-learning-based method to predict virus-host interactions at both protein and organism levels. Our approach revealed five potential infection targets of SARS-CoV-2 and 19 highly possible interactions between SARS-CoV-2 proteins and human proteins in the innate immune pathway.

Epidemiology of coronaviruses, genetics, vaccines, and scenario of current pandemic of coronavirus diseases 2019 (COVID-19): a fuzzy set approach

Human coronaviruses (HCoVs) are associated with a range of respiratory complications. In the last two decades, three major outbreaks have been reported due to HCoVs including the current pandemic. In December 2019, a newly emerged virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan city, China. This paper presents a detailed review of the literature and discusses the uncertain spread of coronavirus disease 2019 (COVID-19) using fuzzy set as classical set theory logic to measure uncertainty and vagueness of COVID-19 in China. Our findings show that both infection and death rate touched the peak (normal fuzzy sets) and have shown a decline. The graphs are not convex, which shows that there remains much uncertainty in the spread of COVID-19. Effective vaccines are clearly needed to control and prevent the COVID-19 pandemic.

Pelargonium Extract EPs 7630 in the Treatment of Human Corona Virus-Associated Acute Respiratory Tract Infections - A Secondary Subgroup-Analysis of an Open-Label, Uncontrolled Clinical Trial

Background: Experience in treating human coronavirus (HCoV) infections might help to identify effective compounds against novel coronaviruses. We therefore performed a secondary subgroup-analysis of data from an open-label, uncontrolled clinical trial published in 2015 investigating the proanthocyanidin-rich Pelargonium sidoides extract EPs 7630 in patients with the common cold.

Methods: 120 patients with common cold and at least 2 out of 10 common cold symptoms received one film-coated 20 mg tablet EPs 7630 thrice daily for 10 days in an uncontrolled, interventional multicentre trial (ISRCTN65790556). At baseline, viral nucleic acids were detected by polymerase chain reaction. Common cold-associated symptoms and treatment satisfaction were evaluated after 5 days and at treatment end. Based on the data of patients with proof of viral nucleic acids, we compared the course of the disease in patients with or without HCoV infection.

Results: In 61 patients, viral nucleic acids were detected. Of these, 23 (37.7%) were tested positive for at least one HCoV (HCoV subset) and 38 (62.3%) for other viruses only (non-HCoV subset). Patients of both subsets showed a significant improvement of common cold symptoms already after 5 days of treatment, although the observed change tended to be more pronounced in the HCoV subset. At treatment end, more than 80% of patients of both groups were completely recovered or majorly improved. In both subsets, less than 22% of patients took concomitant paracetamol for antipyresis. The mean number of patients’ days off work or school/college was similar (0.9 ± 2.6 days in HCoV subset vs 1.3 ± 2.8 days in non-HCoV subset). In both groups, most patients were satisfied or very satisfied with EPs 7630 treatment.

Conclusion: EPs 7630 treatment outcomes of common cold patients with confirmed HCoV infection were as favourable as in patients with other viral infections. As this trial was conducted before the pandemic, there is currently no evidence from clinical trials for the efficacy of EPs 7630 in patients with SARS-CoV-2 infection. Dedicated non-clinical studies and clinical trials are required to elucidate the potential of EPs 7630 in the early treatment of HCoV infections.

Comparison of the clinical characteristics and mortality of adults infected with human coronaviruses 229E and OC43

The purpose of the study was to compare clinical characteristics and mortality among adults infected with human coronaviruses (HCoV) 229E and OC43. We conducted a retrospective cohort study of adults (≥ 18 years) admitted to the ward of a university teaching hospital for suspected viral infection from October 2012 to December 2017. Multiplex real-time polymerase chain reaction (PCR) was used to test for respiratory viruses. Multivariate logistic regression was used to compare mortality among patients with HCoV 229E and HCoV OC43 infections. The main outcome was 30-day all-cause mortality. Of 8071 patients tested, 1689 were found to have a respiratory virus infection. Of these patients, 133 had HCoV infection, including 12 mixed infections, 44 HCoV 229E infections, and 77 HCoV OC43 infections. HCoV 229E infections peaked in January and February, while HCoV OC43 infections occurred throughout the year. The 30-day all-cause mortality was 25.0% among patients with HCoV 229E infection, and 9.1% among patients with HCoV OC43 infection (adjusted odds ratio: 3.58, 95% confidence interval: 1.19–10.75). Infections with HCoVs 229E and OC43 appear to have different seasonal patterns, and HCoV 229E might be more virulent than HCoV OC43.

Molecular Elucidation and Therapeutic Targeting for combating COVID19: Current Scenario and Future Prospective

A corona virus disease 2019 (COVID-19) is a contagious disease which is caused by a novel corona virus. Human corona virus (HCoV) recognized as one of the most rapidly evolving viruses owing to its high genomic nucleotide substitution rates and recombination. Among the severe acute respiratory syndrome (SARS) and Middle-East respiratory syndrome (MERS), COVID-19 has spread more rapidly and increased the level of globalization and adaptation of the virus in every environmental condition due to their high rate of molecular diversity. The whole article highlights the general characteristics of corona virus, their molecular diversity, and molecular protein targeting against COVID-19 with their newer approaches. Through this review, an attempt has made to critically evaluate the recent advances and future aspects helpful to the treatment of COVID-19 based on the present understanding of SARS-CoV-2 infections, which may help offer new insights and potential therapeutic targets for the treatment of the COVID-19.

Improved plaque assay for human coronaviruses 229E and OC43

In light of the COVID-19 pandemic, studies that work to understand SARS-CoV-2 are urgently needed. In turn, the less severe human coronaviruses such as HCoV-229E and OC43 are drawing newfound attention. These less severe coronaviruses can be used as a model to facilitate our understanding of the host immune response to coronavirus infection. SARS-CoV-2 must be handled under biosafety level 3 (BSL-3) conditions. Therefore, HCoV-229E and OC43, which can be handled at BSL-2 provide an alternative to SARS-CoV-2 for preclinical screening and designing of antivirals. However, to date, there is no published effective and efficient method to titrate HCoVs other than expensive indirect immunostaining. Here we present an improved approach using an agarose-based conventional plaque assay to titrate HCoV 229E and OC43 with mink lung epithelial cells, Mv1Lu. Our results indicate that titration of HCoV 229E and OC43 with Mv1Lu is consistent and reproducible. The titers produced are also comparable to those produced using human rhabdomyosarcoma (RD) cells. More importantly, Mv1Lu cells display a higher tolerance for cell-cell contact stress, decreased temperature sensitivity, and a faster growth rate. We believe that our improved low-cost plaque assay can serve as an easy tool for researchers conducting HCoV research.

Age-related susceptibility to coronavirus infections: role of impaired and dysregulated host immunity

Human coronaviruses (hCoVs) cause severe respiratory illness in the elderly. Age-related impairments in innate immunity and suboptimal virus-specific T cell and antibody responses are believed to cause severe disease upon respiratory virus infections. This phenomenon has recently received increased attention, as elderly patients are at substantially elevated risk for severe COVID-19 disease and experience increased rates of mortality following SARS-CoV-2 infection compared with younger populations. However, the basis for age-related fatal pneumonia following pathogenic hCoVs is not well understood. In this Review, we provide an overview of our current understanding of hCoV-induced fatal pneumonia in the elderly. We describe host immune response to hCoV infections derived from studies of young and aged animal models and discuss the potential role of age-associated increases in sterile inflammation (inflammaging) and virus-induced dysregulated inflammation in causing age-related severe disease. We also highlight the existing gaps in our knowledge about virus replication and host immune responses to hCoV infection in young and aged individuals.

Complicating Infections Associated with Common Endemic Human Respiratory Coronaviruses

Coronaviruses OC43, 229E, NL63, and HKU1 are endemic human respiratory coronaviruses that typically cause mild to moderate upper respiratory infections, similar to the common cold. They also may cause simple and complicated lower respiratory infections, otitis media, asthma exacerbations, gastroenteritis, and a few systemic complications. These viruses are usually seasonal (with winter dominance) and affect nearly all age groups. The seasonal and annual variation in virus prevalence has implications for understanding the concept of acquired immunity and its persistence or diminution. Coronaviruses generally have outbreak potential in susceptible populations of any age, particularly in patients with comorbidities, who tend to have increased clinical disease. These 4 coronaviruses are often found in the context of what appears to be coinfection with other pathogens, but especially other viruses. If coronaviruses are not specifically tested for, the sole detection of a viral copathogen would suggest the pathogen is the causative agent, when a coronavirus may be culpable, or both. The detection of these viruses in circumstances where respiratory viruses are generally sought in clinical samples is, therefore, justified. These pathogens can be chronically shed from the respiratory tract, which is more likely to occur among immunocompromised and complicated patients. These viruses share the potential for genetic drift. The genome is among the largest of RNA viruses, and the capability of these viruses to further change is likely underestimated. Given the potential disease among humans, it is justified to search for effective antiviral chemotherapy for these viruses and to consider uses in niche situations should effective therapy be defined. Whereas SARS-CoV-2 may follow the epidemiological pattern of SARS-CoV and extinguish slowly over time, there is yet concern that SARS-CoV-2 may establish itself as an endemic human respiratory coronavirus similar to OC43, 2299E, NL63, and HKU1. Until sufficient data are acquired to better understand the potential of SARS-CoV-2, continued work on antiviral therapy and vaccination is imperative.

COVID-19 Susceptibility in chronic obstructive pulmonary disease

In barely nine months, the pandemic known as COVID-19 has spread over 200 countries, affecting more than 22 million people and causing over than 786 000 deaths. Elderly people and patients with previous comorbidities such as hypertension and diabetes are at an increased risk to suffer a poor prognosis after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although the same could be expected from patients with chronic obstructive pulmonary disease (COPD), current epidemiological data are conflicting. This could lead to a reduction of precautionary measures in these patients, in the context of a particularly complex global health crisis. Most COPD patients have a long history of smoking or exposure to other harmful particles or gases, capable of impairing pulmonary defences even years after the absence of exposure. Moreover, COPD is characterized by an ongoing immune dysfunction, which affects both pulmonary and systemic cellular and molecular inflammatory mediators. Consequently, increased susceptibility to viral respiratory infections have been reported in COPD, often worsened by bacterial co-infections and leading to serious clinical outcomes. The present paper is an up-to-date review that discusses the available research regarding the implications of coronavirus infection in COPD. Although validation in large studies is still needed, COPD likely increases SARS-CoV-2 susceptibility and increases COVID-19 severity. Hence, specific mechanisms to monitor and assess COPD patients should be addressed in the current pandemic.

Can Activation of NRF2 Be a Strategy against COVID-19?

Acute respiratory distress syndrome (ARDS) caused by SARS-CoV-2 is largely the result of a dysregulated host response, followed by damage to alveolar cells and lung fibrosis. Exacerbated proinflammatory cytokines release (cytokine storm) and loss of T lymphocytes (leukopenia) characterize the most aggressive presentation. We propose that a multifaceted anti-inflammatory strategy based on pharmacological activation of nuclear factor erythroid 2 p45-related factor 2 (NRF2) can be deployed against the virus. The strategy provides robust cytoprotection by restoring redox and protein homeostasis, promoting resolution of inflammation, and facilitating repair. NRF2 activators such as sulforaphane and bardoxolone methyl are already in clinical trials. The safety and efficacy information of these modulators in humans, together with their well-documented cytoprotective and anti-inflammatory effects in preclinical models, highlight the potential of this armamentarium for deployment to the battlefield against COVID-19.

The Immune Response and Immunopathology of COVID-19

Coronaviruses were first discovered in the 1960s and are named due to their crown-like shape. Sometimes, but not often, a coronavirus can infect both animals and humans. An acute respiratory disease, caused by a novel coronavirus (severe acute respiratory syndrome coronavirus-2 or SARS-CoV-2 previously known as 2019-nCoV) was identified as the cause of coronavirus disease 2019 (COVID-19) as it spread throughout China and subsequently across the globe. As of 14th July 2020, a total of 13.1 million confirmed cases globally and 572,426 deaths had been reported by the World Health Organization (WHO). SARS-CoV-2 belongs to the β-coronavirus family and shares extensive genomic identity with bat coronavirus suggesting that bats are the natural host. SARS-CoV-2 uses the same receptor, angiotensin-converting enzyme 2 (ACE2), as that for SARS-CoV, the coronavirus associated with the SARS outbreak in 2003. It mainly spreads through the respiratory tract with lymphopenia and cytokine storms occuring in the blood of subjects with severe disease. This suggests the existence of immunological dysregulation as an accompanying event during severe illness caused by this virus. The early recognition of this immunological phenotype could assist prompt recognition of patients who will progress to severe disease. Here we review the data of the immune response during COVID-19 infection. The current review summarizes our understanding of how immune dysregulation and altered cytokine networks contribute to the pathophysiology of COVID-19 patients.

Relative Severity of Common Human Coronaviruses and Influenza in Patients Hospitalized With Acute Respiratory Infection: Results From 8-Year Hospital-Based Surveillance in Quebec, Canada

Background

Few data exist about the role of common human coronaviruses (HCoV) in patients hospitalized for acute respiratory illness (ARI) and the severity of these infections compared to influenza.

Methods

Prospective data on virus etiology of ARI hospitalizations during the peaks of 8 influenza seasons (2011-12 to 2018-19) in Quebec, Canada, was used to compare patients with HCoV to those with influenza infections; generalized estimation equations models were used for multivariate analyses.

Results

We identified 340 HCoV infections which affected 11.6%(n=136) of children and 5.2%(n=204) of adults hospitalized with ARI. The majority of children (75%) with HCoV infections were also coinfected with other respiratory viruses compared to 24% of the adults (p<0.0001). No deaths were recorded in children; 5.8% of adults with HCoV monoinfection compared to 4.2% of those with influenza monoinfection died (p=0.226). The risk of pneumonia was non-significantly lower in children with HCoV than with influenza but similarly high in adults. Markers of severity (length-of-stay, intensive-care admissions and case-fatality ratio) were comparable between these infections in multivariate analyses, both in children and adults.

Conclusions

In children and adults hospitalized with ARI, HCoV infections were less frequent than influenza infections, but HCoV monoinfections were as severe as influenza monoinfections.

A Universal Design of Betacoronavirus Vaccines against COVID-19, MERS, and SARS

Vaccines are urgently needed to control the ongoing pandemic COVID-19 and previously emerging MERS/SARS caused by coronavirus (CoV) infections. The CoV spike receptor-binding domain (RBD) is an attractive vaccine target but is undermined by limited immunogenicity. We describe a dimeric form of MERS-CoV RBD that overcomes this limitation. The RBD-dimer significantly increased neutralizing antibody (NAb) titers compared to conventional monomeric form and protected mice against MERS-CoV infection. Crystal structure showed RBD-dimer fully exposed dual receptor-binding motifs, the major target for NAbs. Structure-guided design further yielded a stable version of RBD-dimer as a tandem repeat single-chain (RBD-sc-dimer) which retained the vaccine potency. We generalized this strategy to design vaccines against COVID-19 and SARS, achieving 10- to 100-fold enhancement of NAb titers. RBD-sc-dimers in pilot scale production yielded high yields, supporting their scalability for further clinical development. The framework of immunogen design can be universally applied to other beta-CoV vaccines to counter emerging threats.

Gas Plasma Technology-An Asset to Healthcare During Viral Pandemics Such as the COVID-19 Crisis?

The COVID-19 crisis profoundly disguised the vulnerability of human societies and healthcare systems in the situation of a pandemic. In many instances, it became evident that the quick and safe reduction of viral load and spread is the foremost principle in the successful management of such a pandemic. However, it became also clear that many of the established routines in healthcare are not always sufficient to cope with the increased demand for decontamination procedures of items, healthcare products, and even infected tissues. For the last 25 years, the use of gas plasma technology has sparked a tremendous amount of literature on its decontaminating properties, especially for heat-labile targets, such as polymers and tissues, where chemical decontamination often is not appropriate. However, while the majority of earlier work focused on bacteria, only relatively few reports are available on the inactivation of viruses. We here aim to provide a perspective for the general audience of the chances and opportunities of gas plasma technology for supporting healthcare during viral pandemics such as the COVID-19 crisis. This includes possible real-world plasma applications, appropriate laboratory viral test systems, and critical points on the technical and safety requirements of gas plasmas for virus inactivation.

Cross-immunity between respiratory coronaviruses may limit COVID-19 fatalities

Of the seven coronaviruses associated with disease in humans, SARS-CoV, MERS-CoV and SARS-CoV-2 cause considerable mortality but also share significant sequence homology, and potentially antigenic epitopes capable of inducing an immune response. The degree of similarity is such that perhaps prior exposure to one virus could confer partial immunity to another. Indeed, data suggests a considerable amount of cross-reactivity and recognition by the hosts immune response between different coronavirus infections. While the ongoing COVID-19 outbreak rapidly overwhelmed medical facilities of particularly Europe and North America, accounting for 78% of global deaths, only 8% of deaths have occurred in Asia where the outbreak originated. Interestingly, Asia and the Middle East have previously experienced multiple rounds of coronavirus infections, perhaps suggesting buildup of acquired immunity to the causative SARS-CoV-2 that underlies COVID-19. This article hypothesizes that a causative factor underlying such low morbidity in these regions is perhaps (at least in part) due to acquired immunity from multiple rounds of coronavirus infections and discusses the mechanisms and recent evidence to support such assertions. Further investigations of such phenomenon would allow us to examine strategies to confer protective immunity, perhaps aiding vaccine development.

On the Coronaviruses and Their Associations with the Aquatic Environment and Wastewater

The outbreak of Coronavirus Disease 2019 (COVID-19), a severe respiratory disease caused by betacoronavirus SARS-CoV-2, in 2019 that further developed into a pandemic has received an unprecedented response from the scientific community and sparked a general research interest into the biology and ecology of Coronaviridae, a family of positive-sense single-stranded RNA viruses. Aquatic environments, lakes, rivers and ponds, are important habitats for bats and birds, which are hosts for various coronavirus species and strains and which shed viral particles in their feces. It is therefore of high interest to fully explore the role that aquatic environments may play in coronavirus spread, including cross-species transmissions. Besides the respiratory tract, coronaviruses pathogenic to humans can also infect the digestive system and be subsequently defecated. Considering this, it is pivotal to understand whether wastewater can play a role in their dissemination, particularly in areas with poor sanitation. This review provides an overview of the taxonomy, molecular biology, natural reservoirs and pathogenicity of coronaviruses; outlines their potential to survive in aquatic environments and wastewater; and demonstrates their association with aquatic biota, mainly waterfowl. It also calls for further, interdisciplinary research in the field of aquatic virology to explore the potential hotspots of coronaviruses in the aquatic environment and the routes through which they may enter it.

Prevalence and clinical impact of VIral Respiratory tract infections in patients hospitalized for Community-Acquired Pneumonia: the VIRCAP study

Prevalence and clinical impact of viral respiratory tract infections (VRTIs) on community-acquired pneumonia (CAP) has not been well defined so far. The aims of this study were to investigate the prevalence and the clinical impact of VRTIs in patients with CAP. Prospective study involving adult patients consecutively admitted at medical wards for CAP and tested for VRTIs by real-time PCR on pharyngeal swab. Patients' features were evaluated with regard to the presence of VRTI and aetiology of CAP. Clinical failure was a composite endpoint defined by worsening of signs and symptoms requiring escalation of antibiotic treatment or ICU admission or death within 30 days. 91 patients were enrolled, mean age 65.7 ± 10.6 years, 50.5% female. 62 patients (68.2%) had no viral co-infection while in 29 patients (31.8%) a VRTI was detected; influenza virus was the most frequently identified (41.9%). The two groups were similar in terms of baseline features. In presence of a VRTI, pneumonia severity index (PSI) was more frequently higher than 91 and patients had received less frequently pre-admission antibiotic therapy (adjusted OR 2.689, 95% CI 1.017-7.111, p = 0.046; adjusted OR 0.143, 95% CI 0.030-0.670, p = 0.014). Clinical failure and antibiotic therapy duration were similar with regards to the presence of VRTI and the aetiology of CAP. VRTIs can be detected in almost a third of adults with CAP; influenza virus is the most relevant one. VRTI was associated with higher PSI at admission, but it does not affect patients' outcome.

Structural and Functional Basis of SARS-CoV-2 Entry by Using Human ACE2

The recent emergence of a novel coronavirus (SARS-CoV-2) in China has caused significant public health concerns. Recently, ACE2 was reported as an entry receptor for SARS-CoV-2. In this study, we present the crystal structure of the C-terminal domain of SARS-CoV-2 (SARS-CoV-2-CTD) spike (S) protein in complex with human ACE2 (hACE2), which reveals a hACE2-binding mode similar overall to that observed for SARS-CoV. However, atomic details at the binding interface demonstrate that key residue substitutions in SARS-CoV-2-CTD slightly strengthen the interaction and lead to higher affinity for receptor binding than SARS-RBD. Additionally, a panel of murine monoclonal antibodies (mAbs) and polyclonal antibodies (pAbs) against SARS-CoV-S1/receptor-binding domain (RBD) were unable to interact with the SARS-CoV-2 S protein, indicating notable differences in antigenicity between SARS-CoV and SARS-CoV-2. These findings shed light on the viral pathogenesis and provide important structural information regarding development of therapeutic countermeasures against the emerging virus.

Structural and Functional Basis of SARS-CoV-2 Entry by Using Human ACE2

The recent emergence of a novel coronavirus (SARS-CoV-2) in China has caused significant public health concerns. Recently, ACE2 was reported as an entry receptor for SARS-CoV-2. In this study, we present the crystal structure of the C-terminal domain of SARS-CoV-2 (SARS-CoV-2-CTD) spike (S) protein in complex with human ACE2 (hACE2), which reveals a hACE2-binding mode similar overall to that observed for SARS-CoV. However, atomic details at the binding interface demonstrate that key residue substitutions in SARS-CoV-2-CTD slightly strengthen the interaction and lead to higher affinity for receptor binding than SARS-RBD. Additionally, a panel of murine monoclonal antibodies (mAbs) and polyclonal antibodies (pAbs) against SARS-CoV-S1/receptor-binding domain (RBD) were unable to interact with the SARS-CoV-2 S protein, indicating notable differences in antigenicity between SARS-CoV and SARS-CoV-2. These findings shed light on the viral pathogenesis and provide important structural information regarding development of therapeutic countermeasures against the emerging virus.

Advances in the relationship between coronavirus infection and cardiovascular diseases

The outbreak of coronavirus disease 2019 (COVID-19) has once again aroused people's concern about coronavirus. Seven human coronaviruses (HCoVs) have been discovered so far, including HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU115, severe acute respiratory syndrome coronavirus, Middle East respiratory syndrome coronavirus and severe acute respiratory syndrome coronavirus 2. Existing studies show that the cardiovascular disease increased the incidence and severity of coronavirus infection. At the same time, myocardial injury caused by coronavirus infection is one of the main factors contributing to poor prognosis. In this review, the recent clinical findings about the relationship between coronaviruses and cardiovascular diseases and the underlying pathophysiological mechanisms are discussed. This review aimed to provide assistance for the prevention and treatment of COVID-19.

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

Antibodies to coronaviruses are higher in older compared with younger adults and binding antibodies are more sensitive than neutralizing antibodies in identifying coronavirus-associated illnesses

Human coronaviruses (HCoV) are common causes of respiratory illnesses (RI) despite preexisting humoral immunity. Sera were obtained near the onset of RI and 3 to 4 weeks later as part of a prospective study of 200 subjects evaluated for RI from 2009 to 2013. Antibodies against common HCoV strains were measured by enzyme‐linked immunosorbent assay and neutralization assay comparing older adults with cardiopulmonary diseases (99 subjects) to younger, healthy adults (101 subjects). Virus shedding was detected in respiratory secretions by polymerase chain reaction. Of 43 HCoV‐associated illnesses, 15 (35%) occurred in 14 older adults (aged ≥60 years) and 28 (65%) in 28 younger adults (aged 21‐40 years). Binding and neutralizing antibodies were higher in older adults. Only 16 (35.7%) of RI with increases in binding antibodies also had increases in neutralizing antibodies to HCoV. Increases in binding antibodies with RI were more frequent than increased neutralizing antibodies and virus shedding, and more frequent in younger compared to older adults. Functional neutralizing antibodies were not stimulated as often as binding antibodies, explaining in part a susceptibility to reinfection with HCoV. Monitoring binding antibodies may be more sensitive for the serologic detection of HCoV infections.

Antibodies to common coronaviruses (HCoV) were higher in older than younger adults.

Antibodies to HCoV can be cross‐reactive between strains.

More HCoV‐related respiratory illnesses were detected in younger than older adults, and binding antibodies to HCoV increased with respiratory illness more frequently than neutralizing antibodies.

There were correlations between binding and neutralizing antibodies, especially to related HCoV strains in convalescent sera.

Pre‐existing antibodies to HCoV may not necessarily be protective against repeated infections and lower rates of neutralizing antibody stimulation may contribute to susceptibility to re‐infection.

Assessment of binding antibodies to HCoV may be useful in seroepidemiologic studies of HCoV infections.

Recent discovery and development of inhibitors targeting coronaviruses

Human coronaviruses (CoVs) are enveloped viruses with a positive-sense single-stranded RNA genome. Currently, six human CoVs have been reported including human coronavirus 229E (HCoV-229E), OC43 (HCoV-OC43), NL63 (HCoV-NL63), HKU1 (HCoV-HKU1), severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), and MiddleEast respiratory syndrome (MERS) coronavirus (MERS-CoV). They cause moderate to severe respiratory and intestinal infections in humans. In this review, we focus on recent advances in the research and development of small-molecule anti-human coronavirus therapies targeting different stages of the CoV life cycle.

Human Coronavirus: Host-Pathogen Interaction

Human coronavirus (HCoV) infection causes respiratory diseases with mild to severe outcomes. In the last 15 years, we have witnessed the emergence of two zoonotic, highly pathogenic HCoVs: severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). Replication of HCoV is regulated by a diversity of host factors and induces drastic alterations in cellular structure and physiology. Activation of critical signaling pathways during HCoV infection modulates the induction of antiviral immune response and contributes to the pathogenesis of HCoV. Recent studies have begun to reveal some fundamental aspects of the intricate HCoV-host interaction in mechanistic detail. In this review, we summarize the current knowledge of host factors co-opted and signaling pathways activated during HCoV infection, with an emphasis on HCoV-infection-induced stress response, autophagy, apoptosis, and innate immunity. The cross talk among these pathways, as well as the modulatory strategies utilized by HCoV, is also discussed.

A pan-coronavirus fusion inhibitor targeting the HR1 domain of human coronavirus spike

Continuously emerging highly pathogenic human coronaviruses (HCoVs) remain a major threat to human health, as illustrated in past SARS-CoV and MERS-CoV outbreaks. The development of a drug with broad-spectrum HCoV inhibitory activity would address this urgent unmet medical need. Although previous studies have suggested that the HR1 of HCoV spike (S) protein is an important target site for inhibition against specific HCoVs, whether this conserved region could serve as a target for the development of broad-spectrum pan-CoV inhibitor remains controversial. Here, we found that peptide OC43-HR2P, derived from the HR2 domain of HCoV-OC43, exhibited broad fusion inhibitory activity against multiple HCoVs. EK1, the optimized form of OC43-HR2P, showed substantially improved pan-CoV fusion inhibitory activity and pharmaceutical properties. Crystal structures indicated that EK1 can form a stable six-helix bundle structure with both short α-HCoV and long β-HCoV HR1s, further supporting the role of HR1 region as a viable pan-CoV target site.

Viral pathogens associated with acute respiratory illness in hospitalized adults and elderly from Zagreb, Croatia, 2016 to 2018

Aims

To investigate the viral etiology of acute respiratory infection (ARI) in hospitalized adults and elderly patients in Croatia, compare the prevalence of detected viruses, and to determine clinical characteristics and seasonal occurrence of investigated infections.

Methods

From January 2016 to June 2018, a total of 182 adult patients presented with symptoms of ARI and admitted to the hospital were tested for 15 respiratory viruses by multiplex reverse‐transcription polymerase chain reaction. Clinical data were collected by retrospective analysis of the patient's chart.

Results

A virus was identified in 106 (58.5%) of the patients. The most commonly detected virus was influenza virus (41.5%), followed by respiratory syncytial virus (13.8%), human metapneumovirus (13.0%), parainfluenza viruses (12.2%), rhinoviruses (11.4%), adenovirus and coronaviruses with equal frequencies (3.3%), and enterovirus (1.6%). The serum level of C‐reactive protein and white blood cell count were significantly lower in patients with respiratory viruses identified when compared with those in whom no virus was detected (P < 0.001 and P = 0.007, respectively). There were no differences in clinical symptoms according to the type of the detected virus, except for more frequent illness exposure recall for influenza infection ( P = 0.010). Influenza, parainfluenza, and pneumoviruses were detected mostly in winter months, while rhinoviruses in autumn and spring.

Conclusions

In addition to influenza, pneumoviruses, rhinoviruses, and parainfluenza viruses play an important role in etiology of ARIs in adults. Fast and accurate laboratory diagnosis for respiratory viruses in routine practice is needed for clinicians optimally manage patients with ARI and potentially avoid the unnecessary use of antimicrobial drugs.

Respiratory syncytial virus-associated illness in adults with advanced chronic obstructive pulmonary disease and/or congestive heart failure

BACKGROUND

Respiratory syncytial virus (RSV) is recognized as a serious pathogen in people with chronic cardiopulmonary conditions. Immunoprophylaxis might be considered for adults at high-risk for frequent and severe RSV infection. Thus, we studied the incidence of RSV-related medically attended acute respiratory illness (MARI) in adults with severe chronic obstructive pulmonary disease (COPD) and/or congestive heart failure (CHF).

METHODS

Subjects ≥50 years of age with Gold Class III/IV COPD and/or American Heart Association class III/IV CHF and exposure to children ≥once per month were recruited. Subjects were evaluated over 1.5 to 2.5 years for RSV-associated MARI, defined as polymerase chain reaction (PCR) and/or seroresponse.

RESULTS

Four hundred forty-five subjects were enrolled between October 2011 and May 2012. Overall, 99 RSV infections were documented by PCR or serology for a cumulative incidence of 22.2%. Of these, 42 (9.4%) subjects had protocol-specified RSV-MARI for an incidence of 4.68/100 patient-seasons. All-cause MARI was common (63.85/100 patient-seasons) with rhinovirus most commonly identified.

CONCLUSION

RSV infection was common in adults with severe COPD and/or advanced CHF. Given the severity of underlying cardiopulmonary diseases in the study population, most illnesses were surprisingly mild. Thus, active immunization rather than passive immunoprophylaxis with monoclonal antibodies may be a more cost-effective strategy.

Early events during human coronavirus OC43 entry to the cell

The Coronaviridae family clusters a number of large RNA viruses, which share several structural and functional features. However, members of this family recognize different cellular receptors and exploit different entry routes, what affects their species specificity and virulence. The aim of this study was to determine how human coronavirus OC43 enters the susceptible cell. Using confocal microscopy and molecular biology tools we visualized early events during infection. We found that the virus employs caveolin-1 dependent endocytosis for the entry and the scission of virus-containing vesicles from the cell surface is dynamin-dependent. Furthermore, the vesicle internalization process requires actin cytoskeleton rearrangements. With our research we strove to broaden the understanding of the infection process, which in future may be beneficial for the development of a potential therapeutics.

Peptide-Based Membrane Fusion Inhibitors Targeting HCoV-229E Spike Protein HR1 and HR2 Domains

Human coronavirus 229E (HCoV-229E) infection in infants, elderly people, and immunocompromised patients can cause severe disease, thus calling for the development of effective and safe therapeutics to treat it. Here we reported the design, synthesis and characterization of two peptide-based membrane fusion inhibitors targeting HCoV-229E spike protein heptad repeat 1 (HR1) and heptad repeat 2 (HR2) domains, 229E-HR1P and 229E-HR2P, respectively. We found that 229E-HR1P and 229E-HR2P could interact to form a stable six-helix bundle and inhibit HCoV-229E spike protein-mediated cell-cell fusion with IC₅₀ of 5.7 and 0.3 µM, respectively. 229E-HR2P effectively inhibited pseudotyped and live HCoV-229E infection with IC₅₀ of 0.5 and 1.7 µM, respectively. In a mouse model, 229E-HR2P administered intranasally could widely distribute in the upper and lower respiratory tracts and maintain its fusion-inhibitory activity. Therefore, 229E-HR2P is a promising candidate for further development as an antiviral agent for the treatment and prevention of HCoV-229E infection.