Coronavirus HKU1 in an Italian pre-term infant with bronchiolitis

A Systematic Review on COVID-19 Vaccine Strategies, Their Effectiveness, and Issues

COVID-19 vaccines are indispensable, with the number of cases and mortality still rising, and currently no medicines are routinely available for reducing morbidity and mortality, apart from dexamethasone, although others are being trialed and launched. To date, only a limited number of vaccines have been given emergency use authorization by the US Food and Drug Administration and the European Medicines Agency. There is a need to systematically review the existing vaccine candidates and investigate their safety, efficacy, immunogenicity, unwanted events, and limitations. The review was undertaken by searching online databases, i.e., Google Scholar, PubMed, and ScienceDirect, with finally 59 studies selected. Our findings showed several types of vaccine candidates with different strategies against SARS-CoV-2, including inactivated, mRNA-based, recombinant, and nanoparticle-based vaccines, are being developed and launched. We have compared these vaccines in terms of their efficacy, side effects, and seroconversion based on data reported in the literature. We found mRNA vaccines appeared to have better efficacy, and inactivated ones had fewer side effects and similar seroconversion in all types of vaccines. Overall, global variant surveillance and systematic tweaking of vaccines, coupled with the evaluation and administering vaccines with the same or different technology in successive doses along with homologous and heterologous prime-booster strategy, have become essential to impede the pandemic. Their effectiveness appreciably outweighs any concerns with any adverse events.

Children in Coronaviruses' Wonderland: What Clinicians Need to Know

Human coronaviruses (HCoVs) commonly cause mild upper-respiratory tract illnesses but can lead to more severe and diffusive diseases. A variety of signs and symptoms may be present, and infections can range in severity from the common cold and sore throat to more serious laryngeal or tracheal infections, bronchitis, and pneumonia. Among the seven coronaviruses that affect humans (SARS)-CoV, the Middle East respiratory syndrome (MERS)-CoV, and the most recent coronavirus disease 2019 (COVID-19) represent potential life-threatening diseases worldwide. In adults, they may cause severe pneumonia that evolves in respiratory distress syndrome and multiorgan failure with a high mortality rate. Children appear to be less susceptible to develop severe clinical disease and present usually with mild and aspecific symptoms similar to other respiratory infections typical of childhood. However, some children, such as infants, adolescents, or those with underlying diseases may be more at-risk categories and require greater caution from clinicians. Available data on pediatric coronavirus infections are rare and scattered in the literature. The purpose of this review is to provide to clinicians a complete and updated panel useful to recognize and characterize the broad spectrum of clinical manifestations of coronavirus infections in the pediatric age.

Coronavirus HKU 1 infection with bronchiolitis, pericardial effusion and acute respiratory failure in obese adult female

Seven species of coronavirus cause acute respiratory illness in humans. Coronavirus HKU 1 (CoV HKU 1) was first described in 2005 in an adult patient with pneumonia in Hong Kong. Although it is a well-known respiratory tract pathogen, there is not much information about its role in hospitalized adults, especially in southern Europe. Here, we describe a case of radiologically demonstrated CoV HKU 1-related bronchiolitis with acute respiratory failure in an adult female without significant comorbidities except obesity.

Etiology and clinical features of viral bronchiolitis in infancy

BACKGROUND

Bronchiolitis is a common lower respiratory tract infection in infancy. The aim of this review is to present the clinical profile of viral bronchiolitis, the different culprit viruses and the disease severity in relation to the viral etiology.

DATA SOURCES

Databases including PubMed and Google Scholar were searched for articles about the clinical features of bronchiolitis and its viral etiology. The most relevant articles to the scope of this review were analyzed.

RESULTS

Currently there are two main definitions for bronchiolitis which are not identical, the European definition and the American one. The most common viral pathogen that causes bronchiolitis is respiratory syncytial virus which was identified in 1955; now many other viruses have been implicated in the etiology of bronchiolitis such as rhinovirus, adenovirus, metapneumovirus, and bocavirus. Several studies have attempted to investigate the correlation of bronchiolitis severity with the type of detected virus or viruses. However, the results were not consitent.

CONCLUSIONS

For the time being, the diagnosis of bronchiolitis remains clinical. The isolation of the responsible respiratory pathogens does not seem to confer to the prognosis of the disease severity.

The Role of Human Coronaviruses in Children Hospitalized for Acute Bronchiolitis, Acute Gastroenteritis, and Febrile Seizures: A 2-Year Prospective Study

Human coronaviruses (HCoVs) are associated with a variety of clinical presentations in children, but their role in disease remains uncertain. The objective of our prospective study was to investigate HCoVs associations with various clinical presentations in hospitalized children up to 6 years of age. Children hospitalized with acute bronchiolitis (AB), acute gastroenteritis (AGE), or febrile seizures (FS), and children admitted for elective surgical procedures (healthy controls) were included in the study. In patients with AB, AGE, and FS, a nasopharyngeal (NP) swab and blood sample were obtained upon admission and the follow-up visit 14 days later, whereas in children with AGE a stool sample was also acquired upon admission; in healthy controls a NP swab and stool sample were taken upon admission. Amplification of polymerase 1b gene was used to detect HCoVs in the specimens. HCoVs-positive specimens were also examined for the presence of several other viruses. HCoVs were most often detected in children with FS (19/192, 9.9%, 95% CI: 6–15%), followed by children with AGE (19/218, 8.7%, 95% CI: 5.3–13.3%) and AB (20/308, 6.5%, 95% CI: 4.0–9.8%). The presence of other viruses was a common finding, most frequent in the group of children with AB (19/20, 95%, 95% CI: 75.1–99.8%), followed by FS (10/19, 52.6%, 95% CI: 28.9–75.6%) and AGE (7/19, 36.8%, 95% CI: 16.3–61.6%). In healthy control children HCoVs were detected in 3/156 (1.9%, 95% CI: 0.4–5.5%) NP swabs and 1/150 (0.7%, 95% CI: 0.02–3.3%) stool samples. It seems that an etiological role of HCoVs is most likely in children with FS, considering that they had a higher proportion of positive HCoVs results than patients with AB and those with AGE, and had the highest viral load; however, the co-detection of other viruses was 52.6%.

Trial Registration: ClinicalTrials.gov NCT00987519

Prevalence and molecular epidemiology of human coronavirus HKU1 in patients with acute respiratory illness

In 2005, human coronavirus HKU1 (HCoV-HKU1) was isolated and identified from a 71-year-old man with pneumonia in Hong Kong. To identify and classify genotypes of HCoV-HKU1 in Korea, a sensitive, specific, and quantitative real-time polymerase chain reaction (PCR) assay was developed and analyzed the sequences of HCoV-HKU1 isolated in Korea. A total of 1,985 respiratory specimens taken from patients with acute respiratory illness were tested for HCoV-HKU1 from January 2007 to May 2008. The major clinical symptoms associated with HCoV-HKU1 infection were examined statistically and sequence variations of the RNA-dependent RNA polymerase (RdRp), spike, and nucleocapsid genes were also analyzed. Fifty cases (2.5%) HCoV-HKU1 were identified by real-time PCR and viral loads ranged from 6.7 × 10(4) to 1.6 × 10(9)  copies/ml. The clinical symptoms of HCoV-HKU1 infection included rhinorrhea (72%), cough (64%), nasal congestion (56%), fever (32%), sputum (30%), sore throat (18%), chills (16%), postnasal discharge (14%), and tonsillar hypertrophy (10%). There was a seasonal distribution of HCoV-HKU1 infection, peaking in winter and spring. Both genotypes A and B were detected but no recombination between them was found. This is the first report on the identification and genotyping of HCoV-HKU1 as a causative agent of acute respiratory illness in Korea. The data suggest that at least two genotypes, A and B, of HCoV-HKU1 with scattered silent mutations were circulating in Korea from 2007 to 2008.

Culturing the unculturable: human coronavirus HKU1 infects, replicates, and produces progeny virions in human ciliated airway epithelial cell cultures

Culturing newly identified human lung pathogens from clinical sample isolates can represent a daunting task, with problems ranging from low levels of pathogens to the presence of growth suppressive factors in the specimens, compounded by the lack of a suitable tissue culture system. However, it is critical to develop suitable in vitro platforms to isolate and characterize the replication kinetics and pathogenesis of recently identified human pathogens. HCoV-HKU1, a human coronavirus identified in a clinical sample from a patient with severe pneumonia, has been a major challenge for successful propagation on all immortalized cells tested to date. To determine if HCoV-HKU1 could replicate in in vitro models of human ciliated airway epithelial cell cultures (HAE) that recapitulate the morphology, biochemistry, and physiology of the human airway epithelium, the apical surfaces of HAE were inoculated with a clinical sample of HCoV-HKU1 (Cean1 strain). High virus yields were found for several days postinoculation and electron micrograph, Northern blot, and immunofluorescence data confirmed that HCoV-HKU1 replicated efficiently within ciliated cells, demonstrating that this cell type is infected by all human coronaviruses identified to date. Antiserum directed against human leukocyte antigen C (HLA-C) failed to attenuate HCoV-HKU1 infection and replication in HAE, suggesting that HLA-C is not required for HCoV-HKU1 infection of the human ciliated airway epithelium. We propose that the HAE model provides a ready platform for molecular studies and characterization of HCoV-HKU1 and in general serves as a robust technology for the recovery, amplification, adaptation, and characterization of novel coronaviruses and other respiratory viruses from clinical material.

Effects of coronavirus infections in children

The isolation of the coronavirus (CoV) identified as the cause of severe acute respiratory syndrome and the detection of 2 new human CoVs (HCoV-NL63 and HCoV-HKU1) have led to studies of the epidemiology and clinical and socioeconomic effects of infections caused by all HCoVs, including those known since the late 1960s (HCoV-229E and HCoV-OC43). HCoV infections can be associated with respiratory and extrarespiratory manifestations, including central nervous system involvement. Furthermore, unlike other RNA viruses, HCoVs can easily mutate and recombine when different strains infect the same cells and give rise to a novel virus with unpredictable host ranges and pathogenicity. Thus, circulating HCoVs should be closely monitored to detect the spread of particularly virulent strains in the community at an early stage and to facilitate the development of adequate preventive and therapeutic measures.

Coronavirus diversity, phylogeny and interspecies jumping

The SARS epidemic has boosted interest in research on coronavirus biodiversity and genomics. Before 2003, there were only 10 coronaviruses with complete genomes available. After the SARS epidemic, up to December 2008, there was an addition of 16 coronaviruses with complete genomes sequenced. These include two human coronaviruses (human coronavirus NL63 and human coronavirus HKU1), 10 other mammalian coronaviruses [bat SARS coronavirus, bat coronavirus (bat-CoV) HKU2, bat-CoV HKU4, bat-CoV HKU5, bat-CoV HKU8, bat-CoV HKU9, bat-CoV 512/2005, bat-CoV 1A, equine coronavirus, and beluga whale coronavirus] and four avian coronaviruses (turkey coronavirus, bulbul coronavirus HKU11, thrush coronavirus HKU12, and munia coronavirus HKU13). Two novel subgroups in group 2 coronavirus (groups 2c and 2d) and two novel subgroups in group 3 coronavirus (groups 3b and 3c) have been proposed. The diversity of coronaviruses is a result of the infidelity of RNA-dependent RNA polymerase, high frequency of homologous RNA recombination, and the large genomes of coronaviruses. Among all hosts, the diversity of coronaviruses is most evidenced in bats and birds, which may be a result of their species diversity, ability to fly, environmental pressures, and habits of roosting and flocking. The present evidence supports that bat coronaviruses are the gene pools of group 1 and 2 coronaviruses, whereas bird coronaviruses are the gene pools of group 3 coronaviruses. With the increasing number of coronaviruses, more and more closely related coronaviruses from distantly related animals have been observed, which were results of recent interspecies jumping and may be the cause of disastrous outbreaks of zoonotic diseases.

Expression, crystallization and preliminary crystallographic study of human coronavirus HKU1 nonstructural protein 9

Human coronavirus HKU1 (HCoV-HKU1) belongs to coronavirus group II and encodes 16 nonstructural proteins (nsps) which mediate genome replication and transcription. Among these nsps, nsp9 has been shown to possess single-stranded DNA/RNA-binding properties. The gene that encodes HCoV-HKU1 nsp9 was cloned and expressed in Escherichia coli and the protein was subjected to crystallization trials. The crystals diffracted to 2.7 A resolution and belonged to space group P2(1)2(1)2, with unit-cell parameters a = 83.5, b = 88.4, c = 31.2 A, alpha = beta = gamma = 90 degrees and two molecules per asymmetric unit.

Examination of seroprevalence of coronavirus HKU1 infection with S protein-based ELISA and neutralization assay against viral spike pseudotyped virus

Background

Human coronavirus HKU1 (HCoV-HKU1) is a recently identified coronavirus with a global distribution and known to cause mainly respiratory infections.

Objectives

To investigate the seroepidemiology of HKU1 infections in our local population.

Study design

An ELISA-based IgG antibody detection assay using recombinant HCoV-HKU1 nucleocapsid and spike (S) proteins (genotype A) were developed for the diagnosis of CoV-HKU1 infections, Additionally, a neutralization antibody assay using the HCoV-HKU1 pseudotyped virus was developed to detect the presence of neutralizing antibodies in serum with antibody positivity in an S protein-based ELISA.

Results

Results of the recombinant S protein-based ELISA were validated with Western blot, immunofluorescence analysis and flow cytometry. The coupled results demonstrated good correlation with Spearmen's coefficient of 0.94. Seroepidemiological study in a local hospital-based setting using this newly developed ELISA showed steadily increasing HCoV-HKU1 seroprevalence in childhood and early adulthood, from 0% in the age group of <10 years old to a plateau of 21.6% in the age group of 31–40 years old.

Conclusions

Our study demonstrated the usefulness of the S-based ELISA which could be applied to future epidemiological studies of HCoV-HKU1 in other localities.

Spike protein, S, of human coronavirus HKU1: role in viral life cycle and application in antibody detection

We recently described the discovery, genome, clinical features, genotypes and evolution of a novel and global human respiratory virus named human coronavirus HKU1 (HCoV-HKU1) which is not yet culturable. We expressed a C-terminal FLAG-tagged CoV-HKU1 spike (S) protein by the Semliki Forest Virus (SFV) system and investigated its maturation profile. Pulse chase labeling revealed that S-FLAG was expressed as high-mannose N-glycans of monomers and trimers. It was predominantly cleaved into subdomains S1 and S2 during maturation. S1 was secreted into the medium. Immunofluorescence analysis visualized S along the secretory pathway from endoplasmic reticulum to plasma membrane. Cleavage of S and release of HCoV-HKU1 S pseudotyped virus were inhibited by furin or furin-like enzyme inhibitors. The cell-based expressed full-length S-FLAG could be recognized by the convalescent serum obtained from a patient with HCoV-HKU1 pneumonia. The data suggest that the native form of HCoV-HKU1 spike expressed in our system can be used in developing serological diagnostic assay and in understanding the role of S in the viral life cycle.

Structure of the main protease from a global infectious human coronavirus, HCoV-HKU1

The newly emergent human coronavirus HKU1 (HCoV-HKU1) was first identified in Hong Kong in 2005. Infection by HCoV-HKU1 occurs worldwide and causes syndromes such as the common cold, bronchitis, and pneumonia. The CoV main protease (M(pro)), which is a key enzyme in viral replication via the proteolytic processing of the replicase polyproteins, has been recognized as an attractive target for rational drug design. In this study, we report the structure of HCoV-HKU1 M(pro) in complex with a Michael acceptor, inhibitor N3. The structure of HCoV-HKU1 provides a high-quality model for group 2A CoVs, which are distinct from group 2B CoVs such as severe acute respiratory syndrome CoV. The structure, together with activity assays, supports the relative conservation at the P1 position that was discovered by sequencing the HCoV-HKU1 genome. Combined with structural data from other CoV M(pro)s, the HCoV-HKU1 M(pro) structure reported here provides insights into both substrate preference and the design of antivirals targeting CoVs.

Role of respiratory pathogens in infants hospitalized for a first episode of wheezing and their impact on recurrences

In order to evaluate the infectious agents associated with the first episode of severe acute wheezing in otherwise healthy infants and to define the role of each of them in recurrences, 85 patients in Italy, aged <12 months, hospitalized because of a first acute episode of wheezing, were prospectively enrolled between 1 October 2005 and 31 March 2006. Upon enrollment, nasopharyngeal swabs were collected for the real-time PCR detection of respiratory syncytial virus (RSV) types A and B, influenza virus types A and B, adenovirus, parainfluenza viruses types 1, 2, 3 and 4, rhinovirus, human metapneumovirus, human coronavirus types 229E, OC43, NL63, and HKU1, bocavirus, enterovirus, and paraechovirus; nasopharyngeal aspirates were also obtained to detect atypical bacteria. At least one infectious agent was identified in 76 children (89.4%). RSV was the most frequently detected pathogen and its prevalence was significantly higher than that of the other pathogens in both age groups, and significantly higher in the children aged 3-12 months than in those aged <3 months. Only the children with RSV infection experienced recurrent wheezing. Viral load was significantly higher in children with than in those without recurrent wheezing. This study shows that RSV is the main reason for hospitalization during the first wheezing episode in infants, and that it appears to be the only pathogen associated with a high frequency of recurrences. A high viral load seems to be strictly related to the likelihood of recurrence.

Association between high nasopharyngeal viral load and disease severity in children with human metapneumovirus infection

Background

Previous studies have shown that viral genotype and viral load may play a significant role in the pathogenesis of viral infections.

Objectives

The aim of this study was to evaluate these aspects of hMPV infections in children and their household contacts.

Study design

Between 1 November 2003 and 31 March 2004, we prospectively studied 2060 children attending our Emergency Department for acute reasons. Nasopharyngeal swabs were collected upon enrolment and then tested with real-time PCR assays for the major viral causes of respiratory illness.

Results

Sixty children (2.9%) were infected by hMPV: 24 (1.2%) by hMPV A, 14 (0.7%) by hMPV B, 11 (0.5%) by untyped hMPV, and 11 (0.5%) by hMPV and an additional respiratory virus. There were no differences in disease presentation or in clinical or socioeconomic impact in relation to viral genotypes. HMPV viral load was significantly higher in children with lower respiratory tract involvement (p < 0.05), hospitalised children (p < 0.05), and the prevalence of secondary cases of a similar disease in the household of index cases (p < 0.05).

Conclusion

A high hMPV viral load correlated with disease presentation, whereas the overall clinical and socioeconomic burden caused by the two hMPV genotypes was similar.

Impact of human bocavirus on children and their families

This study was planned to investigate the prevalence and clinical features of the illnesses associated with human bocavirus (hBoV) in children with acute disease. We prospectively enrolled all subjects aged less than 15 years attending an emergency room in Milan, Italy, on Wednesdays and Sundays between 1 November 2004 and 31 March 2005 for any acute medical reason, excluding surgical diseases and trauma. Nasopharyngeal swabs were collected at admission to detect hBoV; influenza A and B viruses; respiratory syncytial virus; human metapneumovirus; parainfluenza viruses 1, 2, 3, and 4; rhinovirus; adenovirus; and coronaviruses 229E, OC43, NL63, and HKU1 by real-time PCR. Among the 1,332 enrolled children, hBoV was the fifth most frequently detected virus (7.4%). The rate of hBoV coinfections with other viruses was significantly higher than for the other viruses (50.5% versus 27.5%; P < 0.0001). Eighty-nine of the 99 hBoV-positive children (89.9%) had a respiratory tract infection, and 10 (10.1%) had gastroenteritis. hBoV coinfections had a significantly greater clinical and socioeconomic impact on the infected children and their households than hBoV infection alone. In conclusion, these findings show that the role of hBoV infection alone seems marginal in children attending an emergency room for acute disease; its clinical and socioeconomic importance becomes relevant only when it is associated with other viruses.