Molecular characterization of human coronaviruses and their circulation dynamics in Kenya, 2009-2012

Epidemiology of Human Seasonal Coronaviruses Among People With Mild and Severe Acute Respiratory Illness in Blantyre, Malawi, 2011-2017

BACKGROUND

The aim of this study was to characterize the epidemiology of human seasonal coronaviruses (HCoVs) in southern Malawi.

METHODS

We tested for HCoVs 229E, OC43, NL63, and HKU1 using real-time polymerase chain reaction (PCR) on upper respiratory specimens from asymptomatic controls and individuals of all ages recruited through severe acute respiratory illness (SARI) surveillance at Queen Elizabeth Central Hospital, Blantyre, and a prospective influenza-like illness (ILI) observational study between 2011 and 2017. We modeled the probability of having a positive PCR for each HCoV using negative binomial models, and calculated pathogen-attributable fractions (PAFs).

RESULTS

Overall, 8.8% (539/6107) of specimens were positive for ≥1 HCoV. OC43 was the most frequently detected HCoV (3.1% [191/6107]). NL63 was more frequently detected in ILI patients (adjusted incidence rate ratio [aIRR], 9.60 [95% confidence interval {CI}, 3.25-28.30]), while 229E (aIRR, 8.99 [95% CI, 1.81-44.70]) was more frequent in SARI patients than asymptomatic controls. In adults, 229E and OC43 were associated with SARI (PAF, 86.5% and 89.4%, respectively), while NL63 was associated with ILI (PAF, 85.1%). The prevalence of HCoVs was similar between children with SARI and controls. All HCoVs had bimodal peaks but distinct seasonality.

CONCLUSIONS

OC43 was the most prevalent HCoV in acute respiratory illness of all ages. Individual HCoVs had distinct seasonality that differed from temperate settings.

Global Epidemiology and Seasonality of Human Seasonal Coronaviruses: A Systematic Review

Background

We characterized the global epidemiology and seasonality of human coronaviruses (HCoVs) OC43, NL63, 229E, and HKU1.

Methods

In this systematic review, we searched MEDLINE, EMBASE, Web of Science, SCOPUS, CINAHL, and backward citations for studies published until 1 September 2023. We included studies with ≥12 months of consecutive data and tested for ≥1 HCoV species. Case reports, review articles, animal studies, studies focusing on SARS-CoV-1, SARS-CoV-2, and/or Middle East respiratory syndrome, and those including <100 cases were excluded. Study quality and risk of bias were assessed using Joanna Briggs Institute Critical Appraisal Checklist tools. We reported the prevalence of all HCoVs and individual species. Seasonality was reported for studies that included ≥100 HCoVs annually. This study is registered with PROSPERO, CRD42022330902.

Results

A total of 201 studies (1 819 320 samples) from 68 countries were included. A high proportion were from China (19.4%; n = 39), whereas the Southern Hemisphere was underrepresented. Most were case series (77.1%, n = 155) with samples from secondary care (74.1%, n = 149). Seventeen (8.5%) studies included asymptomatic controls, whereas 76 (37.8%) reported results for all 4 HCoV species. Overall, OC43 was the most prevalent HCoV. Median test positivity of OC43 and NL63 was higher in children, and 229E and HKU1 in adults. Among 18 studies that described seasonality (17 from the Northern Hemisphere), circulation of all HCoVs mostly peaked during cold months.

Conclusions

In our comprehensive review, few studies reported the prevalence of individual HCoVs or seasonality. Further research on the burden and circulation of HCoVs is needed, particularly from Africa, South Asia, and Central/South America.

Predictors of severity and prolonged hospital stay of viral acute respiratory infections (ARI) among children under five years in Burkina Faso, 2016-2019

BACKGROUND

Viruses are the leading etiology of acute respiratory infections (ARI) in children. However, there is limited knowledge on drivers of severe acute respiratory infection (SARI) cases involving viruses. We aimed to identify factors associated with severity and prolonged hospitalization of viral SARI among children < 5 years in Burkina Faso.

METHODS

Data were collected from four SARI sentinel surveillance sites during October 2016 through April 2019. A SARI case was a child < 5 years with an acute respiratory infection with history of fever or measured fever ≥ 38 °C and cough with onset within the last ten days, requiring hospitalization. Very severe ARI cases required intensive care or had at least one danger sign. Oropharyngeal/nasopharyngeal specimens were collected and analyzed by multiplex real-time reverse-transcription polymerase chain reaction (rRT-PCR) using FTD-33 Kit. For this analysis, we included only SARI cases with rRT-PCR positive test results for at least one respiratory virus. We used simple and multilevel logistic regression models to assess factors associated with very severe viral ARI and viral SARI with prolonged hospitalization.

RESULTS

Overall, 1159 viral SARI cases were included in the analysis after excluding exclusively bacterial SARI cases (n = 273)very severe viral ARI cases were common among children living in urban areas (AdjOR = 1.3; 95% CI: 1.1-1.6), those < 3 months old (AdjOR = 1.5; 95% CI: 1.1-2.3), and those coinfected with Klebsiella pneumoniae (AdjOR = 1.9; 95% CI: 1.2-2.2). Malnutrition (AdjOR = 2.2; 95% CI: 1.1-4.2), hospitalization during the rainy season (AdjOR = 1.71; 95% CI: 1.2-2.5), and infection with human CoronavirusOC43 (AdjOR = 3; 95% CI: 1.2-8) were significantly associated with prolonged length of hospital stay (> 7 days).

CONCLUSION

Younger age, malnutrition, codetection of Klebsiella pneumoniae, and illness during the rainy season were associated with very severe cases and prolonged hospitalization of SARI involving viruses in children under five years. These findings emphasize the need for preventive actions targeting these factors in young children.

Seasonality of endemic COVID-19

IMPORTANCE

The seasonality of COVID-19 is important for effective healthcare and public health decision-making. Previous waves of SARS-CoV-2 infections have indicated that the virus will likely persist as an endemic pathogen with distinct surges. However, the timing and patterns of potentially seasonal surges remain uncertain, rendering effective public health policies uninformed and in danger of poorly anticipating opportunities for intervention, such as well-timed booster vaccination drives. Applying an evolutionary approach to long-term data on closely related circulating coronaviruses, our research provides projections of seasonal surges that should be expected at major temperate population centers. These projections enable local public health efforts that are tailored to expected surges at specific locales or regions. This knowledge is crucial for enhancing medical preparedness and facilitating the implementation of targeted public health interventions.

Prevalence and Molecular Epidemiology of Human Coronaviruses in Africa Prior to the SARS-CoV-2 Outbreak: A Systematic Review

Coronaviruses, re-emerging in human populations, cause mild or severe acute respiratory diseases, and occasionally epidemics. This study systematically reviewed human coronavirus (HCoVs) infections in Africa prior to the SARS-CoV-2 outbreak. Forty studies on the prevalence or molecular epidemiology of HCoVs were available from 13/54 African countries (24%). The first published data on HCoV was from South Africa in 2008. Eight studies (20%) reported on HCoV molecular epidemiology. Endemic HCoV prevalence ranged from 0.0% to 18.2%. The prevalence of zoonotic MERS-CoV ranged from 0.0% to 83.5%. Two studies investigated SARS-CoV infection, for which a prevalence of 0.0% was reported. There was heterogeneity in the type of tests used in determining HCoV prevalence. Two studies reported that risk factors for HCoV include exposure to infected animals or humans. The quantity of virologic investigations on HCoV on the African continent was scant, and Africa was not prepared for SARS-CoV-2.

Molecular mechanisms of human coronavirus NL63 infection and replication

Human coronavirus NL63 (HCoV-NL63) is spread globally, causing upper and lower respiratory tract infections mainly in young children. HCoV-NL63 shares a host receptor (ACE2) with severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2 but, unlike them, HCoV-NL63 primarily develops into self-limiting mild to moderate respiratory disease. Although with different efficiency, both HCoV-NL63 and SARS-like CoVs infect ciliated respiratory cells using ACE2 as receptor for binding and cell entry. Working with SARS-like CoVs require access to BSL-3 facilities, while HCoV-NL63 research can be performed at BSL-2 laboratories. Thus, HCoV-NL63 could be used as a safer surrogate for comparative studies on receptor dynamics, infectivity and virus replication, disease mechanism, and potential therapeutic interventions against SARS-like CoVs. This prompted us to review the current knowledge on the infection mechanism and replication of HCoV-NL63. Specifically, after a brief overview on the taxonomy, genomic organization and virus structure, this review compiles the current HCoV-NL63-related research in virus entry and replication mechanism, including virus attachment, endocytosis, genome translation, and replication and transcription. Furthermore, we reviewed cumulative knowledge on the susceptibility of different cells to HCoV-NL63 infection in vitro, which is essential for successful virus isolation and propagation, and contribute to address different scientific questions from basic science to the development and assessment of diagnostic tools, and antiviral therapies. Finally, we discussed different antiviral strategies that have been explored to suppress replication of HCoV-NL63, and other related human coronaviruses, by either targeting the virus or enhancing host antiviral mechanisms.

Screening and identification of potential MERS-CoV papain-like protease (PLpro) inhibitors; Steady-state kinetic and Molecular dynamic studies

MERS-CoV belongs to the coronavirus group. Recent years have seen a rash of coronavirus epidemics. In June 2012, MERS-CoV was discovered in the Kingdom of Saudi Arabia, with 2,591 MERSA cases confirmed by lab tests by the end of August 2022 and 894 deaths at a case-fatality ratio (CFR) of 34.5% documented worldwide. Saudi Arabia reported the majority of these cases, with 2,184 cases and 813 deaths (CFR: 37.2%), necessitating a thorough understanding of the molecular machinery of MERS-CoV. To develop antiviral medicines, illustrative investigation of the protein in coronavirus subunits are required to increase our understanding of the subject. In this study, recombinant expression and purification of MERS-CoV (PLpro), a primary goal for the development of 22 new inhibitors, were completed using a high throughput screening methodology that employed fragment-based libraries in conjunction with structure-based virtual screening. Compounds 2, 7, and 20, showed significant biological activity. Moreover, a docking analysis revealed that the three compounds had favorable binding mood and binding free energy. Molecular dynamic simulation demonstrated the stability of compound 2 (2-((Benzimidazol-2-yl) thio)-1-arylethan-1-ones) the strongest inhibitory activity against the PLpro enzyme. In addition, disubstitutions at the meta and para locations are the only substitutions that may boost the inhibitory action against PLpro. Compound 2 was chosen as a MERS-CoV PLpro inhibitor after passing absorption, distribution, metabolism, and excretion studies; however, further investigations are required.

Cross-species transmission, evolution and zoonotic potential of coronaviruses

Coronaviruses (CoVs) continuously evolve, crossing species barriers and spreading across host ranges. Over the last two decades, several CoVs (HCoV-229E, HCoV-NL63, HCoV-HKU1, HCoV-OC43, SARS-CoV, MERS-CoV, and SARS-CoV-2) have emerged in animals and mammals, causing significant economic and human life losses. Due to CoV cross-species transmission and the evolution of novel viruses, it is critical to identify their natural reservoiurs and the circumstances under which their transmission occurs. In this review, we use genetic and ecological data to disentangle the evolution of various CoVs in wildlife, humans, and domestic mammals. We thoroughly investigate several host species and outline the epidemiology of CoVs toward specific hosts. We also discuss the cross-species transmission of CoVs at the interface of wildlife, animals, and humans. Clarifying the epidemiology and diversity of species reservoirs will significantly impact our ability to respond to the future emergence of CoVs in humans and domestic animals.

Origins and Evolution of Seasonal Human Coronaviruses

Four seasonal human coronaviruses (sHCoVs) are endemic globally (229E, NL63, OC43, and HKU1), accounting for 5-30% of human respiratory infections. However, the epidemiology and evolution of these CoVs remain understudied due to their association with mild symptomatology. Using a multigene and complete genome analysis approach, we find the evolutionary histories of sHCoVs to be highly complex, owing to frequent recombination of CoVs including within and between sHCoVs, and uncertain, due to the under sampling of non-human viruses. The recombination rate was highest for 229E and OC43 whereas substitutions per recombination event were highest in NL63 and HKU1. Depending on the gene studied, OC43 may have ungulate, canine, or rabbit CoV ancestors. 229E may have origins in a bat, camel, or an unsampled intermediate host. HKU1 had the earliest common ancestor (1809-1899) but fell into two distinct clades (genotypes A and B), possibly representing two independent transmission events from murine-origin CoVs that appear to be a single introduction due to large gaps in the sampling of CoVs in animals. In fact, genotype B was genetically more diverse than all the other sHCoVs. Finally, we found shared amino acid substitutions in multiple proteins along the non-human to sHCoV host-jump branches. The complex evolution of CoVs and their frequent host switches could benefit from continued surveillance of CoVs across non-human hosts.

Differential pre-pandemic breast milk IgA reactivity against SARS-CoV-2 and circulating human coronaviruses in Ugandan and American mothers

OBJECTIVE

Uganda has registered fewer coronavirus disease 2019 (COVID-19) cases and deaths per capita than Western countries. The lower numbers of cases and deaths might be due to pre-existing cross-immunity induced by circulating common cold human coronaviruses (HCoVs) before the COVID-19 pandemic. To investigate pre-existing mucosal antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, a comparison was performed of IgA reactivity to SARS-CoV-2 and HCoVs in milk from mothers collected in 2018.

METHODS

Ugandan and United States milk samples were run on an ELISA to measure specific IgA to SARS-CoV-2 and HCoVs NL63, OC43, HKU1, and 229E spike proteins. Pooled plasma from United States SARS-CoV-2-positive and negative cases were positive and negative controls, respectively.

RESULTS

One Ugandan mother had high milk IgA reactivity against all HCoVs and SARS-CoV-2 spike proteins. Ugandan mothers had significantly higher IgA reactivity against the betacoronavirus HCoV-OC43 than United States mothers (P = 0.018). By contrast, United States mothers had significantly higher IgA reactivity against the alphacoronaviruses HCoV-229E and HCoV-NL63 than Ugandan mothers (P < 0.0001 and P = 0.035, respectively).

CONCLUSION

Some Ugandan mothers have pre-existing HCoV-induced IgA antibodies against SARS-CoV-2, which may be passed to infants via breastfeeding.

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.

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.

Etiology and clinical characteristics of SARS-CoV-2 and other human coronaviruses among children in Zhejiang Province, China 2017-2019

BACKGROUND

A novel coronavirus (SARS-CoV-2) emerging has put global public health institutes on high alert. Little is known about the epidemiology and clinical characteristics of human coronaviruses infections in relation to infections with other respiratory viruses.

METHODS

From February 2017 to December 2019, 3660 respiratory samples submitted to Zhejiang Children Hospital with acute respiratory symptoms were tested for four human coronaviruses RNA by a novel two-tube multiplex reverse transcription polymerase chain reaction assays. Samples were also screened for the occurrence of SARS-CoV-2 by reverse transcription-PCR analysis.

RESULTS

Coronavirus RNAs were detected in 144 (3.93%) specimens: HCoV-HKU1 in 38 specimens, HCoV-NL63 in 62 specimens, HCoV-OC43 in 38 specimens and HCoV-229E in 8 specimens. Genomes for SARS-CoV-2 were absent in all specimens by RT-PCR analysis during the study period. The majority of HCoV infections occurred during fall months. No significant differences in gender, sample type, year were seen across species. 37.5 to 52.6% of coronaviruses detected were in specimens testing positive for other respiratory viruses. Phylogenic analysis identified that Zhejiang coronaviruses belong to multiple lineages of the coronaviruses circulating in other countries and areas.

CONCLUSION

Common HCoVs may have annual peaks of circulation in fall months in the Zhejiang province, China. Genetic relatedness to the coronaviruses in other regions suggests further surveillance on human coronaviruses in clinical samples are clearly needed to understand their patterns of activity and role in the emergence of novel coronaviruses.

The history of the emergence and transmission of human coronaviruses

Human coronaviruses are known respiratory pathogens associated with a range of respiratory illnesses, and there are considerable morbidity and hospitalisation amongst immune-compromised individuals of all age groups. The emergence of a highly pathogenic human coronavirus in China in 2019 has confirmed the long-held opinion that these viruses are important emerging and re-emerging pathogens. In this review article, we trace the discovery and emergence of coronaviruses (CoVs) over time since they were first reported. The review article will enrich our understanding on the host range, diversity and evolution, transmission of human CoVs and the threat posed by these viruses circulating in animal populations but overtime have spilled over to humans because of the increased proximity between humans and animals.

Infection patterns of endemic human coronaviruses in rural households in coastal Kenya

Background: The natural history and transmission patterns of endemic human coronaviruses are of increased interest following the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Methods: In rural Kenya 483 individuals from 47 households were followed for six months (2009-10) with nasopharyngeal swabs collected twice weekly regardless of symptoms. A total of 16,918 swabs were tested for human coronavirus (hCoV) OC43, NL63 and 229E and other respiratory viruses using polymerase chain reaction. Results: From 346 (71.6%) household members, 629 hCoV infection episodes were defined, with 36.3% being symptomatic: varying by hCoV type and decreasing with age. Symptomatic episodes (aHR=0.6 (95% CI:0.5-0.8) or those with elevated peak viral load (medium aHR=0.4 (0.3-0.6); high aHR=0.31 (0.2-0.4)) had longer viral shedding compared to their respective counterparts. Homologous reinfections were observed in 99 (19.9%) of 497 first infections. School-age children (55%) were the most common index cases with those having medium (aOR=5.3 (2.3 - 12.0)) or high (8.1 (2.9 - 22.5)) peak viral load most often generating secondary cases. Conclusion: Household coronavirus infection was common, frequently asymptomatic and mostly introduced by school-age children. Secondary transmission was influenced by viral load of index cases. Homologous-type reinfection was common. These data may be insightful for SARS-CoV-2.

MERS-CoV: epidemiology, molecular dynamics, therapeutics, and future challenges

The Severe Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has gained research attention worldwide, given the current pandemic. Nevertheless, a previous zoonotic and highly pathogenic coronavirus, the Middle East Respiratory Syndrome coronavirus (MERS-CoV), is still causing concern, especially in Saudi Arabia and neighbour countries. The MERS-CoV has been reported from respiratory samples in more than 27 countries, and around 2500 cases have been reported with an approximate fatality rate of 35%. After its emergence in 2012 intermittent, sporadic cases, nosocomial infections and many community clusters of MERS continued to occur in many countries. Human-to-human transmission resulted in the large outbreaks in Saudi Arabia. The inherent genetic variability among various clads of the MERS-CoV might have probably paved the events of cross-species transmission along with changes in the inter-species and intra-species tropism. The current review is drafted using an extensive review of literature on various databases, selecting of publications irrespective of favouring or opposing, assessing the merit of study, the abstraction of data and analysing data. The genome of MERS-CoV contains around thirty thousand nucleotides having seven predicted open reading frames. Spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins are the four main structural proteins. The surface located spike protein (S) of betacoronaviruses has been established to be one of the significant factors in their zoonotic transmission through virus-receptor recognition mediation and subsequent initiation of viral infection. Three regions in Saudi Arabia (KSA), Eastern Province, Riyadh and Makkah were affected severely. The epidemic progression had been the highest in 2014 in Makkah and Riyadh and Eastern Province in 2013. With a lurking epidemic scare, there is a crucial need for effective therapeutic and immunological remedies constructed on sound molecular investigations.

Evolutionary dynamics and geographic dispersal of beta coronaviruses in African bats

Bats have been shown to serve as reservoir host of various viral agents including coronaviruses. They have also been associated with the novel coronavirus SARS-CoV-2. This has made them an all important agent for CoV evolution and transmission. Our objective in this study was to investigate the dispersal, phylogenomics and evolution of betacoronavirus (βCoV) among African bats. We retrieved sequence data from established databases such as GenBank and Virus Pathogen Resource, covering the partial RNA dependent RNA polymerase (RdRP) gene of bat coronaviruses from eight African, three Asian, five European, two South American countries and Australia. We analyzed for phylogeographic information relating to genetic diversity and evolutionary dynamics. Our study revealed that majority of the African strains fell within Norbecovirus subgenera, with an evolutionary rate of 1.301 × 10^-3, HPD (1.064 × 10^-3-1.434 × 10^-3) subs/site/year. The African strains diversified into three main subgenera, Norbecovirus, Hibecovirus and Merbecovirus. The time to most common recent ancestor for Norbecovirus strains was 1973, and 2007, for the African Merbecovirus strains. There was evidence of inter species transmission of Norbecovirus among bats in Cameroun and DRC. Phlylogeography showed that there were inter-continental spread of Bt-CoV from Europe, China and Hong Kong into Central and Southern Africa, highlighting the possibility of long distance transmission. Our study has elucidated the possible evolutionary origins of βCoV among African bats; we therefore advocate for broader studies of whole genome sequences of BtCoV to further understand the drivers for their emergence and zoonotic spillovers into human population.

Surveillance of endemic human coronaviruses (HCoV-NL63, OC43 and 229E) associated with childhood pneumonia in Kilifi, Kenya

Introduction: Human coronaviruses (HCoVs) circulate endemically in human populations, often with seasonal variation. We describe the long-term patterns of paediatric disease associated with three of these viruses, HCoV-NL63, OC43 and 229E, in coastal Kenya. Methods: Continuous surveillance of pneumonia admissions was conducted at the Kilifi county hospital (KCH) located in the northern coastal region of Kenya. Children aged <5 years admitted to KCH with clinically defined syndromic severe or very severe pneumonia were recruited. Respiratory samples were taken and tested for 15 virus targets, using real-time polymerase chain reaction. Unadjusted odds ratios were used to estimate the association between demographic and clinical characteristics and HCoV positivity. Results: From 2007 to 2019, we observed 11,445 pneumonia admissions, of which 314 (3.9%) tested positive for at least one of the HCoV types surveyed in the study. There were 129 (41.1%) OC43, 99 (31.5%) 229E, 74 (23.6%) NL63 positive cases and 12 (3.8%) cases of HCoV to HCoV coinfection.  Among HCoV positive cases, 47% (n=147) were coinfected with other respiratory virus pathogens. The majority of HCoV cases were among children aged <1 year (66%, n=208), though there was was no change in the proportion infected by age. HCoV-OC43 was predominant of the three HCoV types throughout the surveillance period. Evidence for seasonality was not identified. Conclusions: Overall, 4% of paediatric pneumonia admissions were associated with three endemic HCoVs, with a high proportion of cases co-occurring with another respiratory virus, no clear seasonal pattern, and with the age-distribution of cases following that of pneumonia admissions (i.e. highest in infants). These observations suggest, at most, a small severe disease contribution of endemic HCoVs in this tropical setting and offer insight into their potential future burden and epidemiological characteristics.

Repurposing Drugs, Ongoing Vaccine, and New Therapeutic Development Initiatives Against COVID-19

As the COVID-19 is still growing throughout the globe, a thorough investigation into the specific immunopathology of SARS-CoV-2, its interaction with the host immune system and pathogen evasion mechanism may provide a clear picture of how the pathogen can breach the host immune defenses in elderly patients and patients with comorbid conditions. Such studies will also reveal the underlying mechanism of how children and young patients can withstand the disease better. The study of the immune defense mechanisms and the prolonged immune memory from patients population with convalescent plasma may help in designing a suitable vaccine candidate not only for the current outbreak but also for similar outbreaks in the future. The vital drug candidates, which are being tested as potential vaccines or therapeutics against COVID-19, include live attenuated vaccine, inactivated or killed vaccine, subunit vaccine, antibodies, interferon treatment, repurposing existing drugs, and nucleic acid-based vaccines. Several organizations around the world have fast-tracked the development of a COVID-19 vaccine, and some drugs already went to phase III of clinical trials. Hence, here, we have tried to take a quick glimpse of the development stages of vaccines or therapeutic approaches to treat this deadly disease.

COVID-19: Emergence of Infectious Diseases, Nanotechnology Aspects, Challenges, and Future Perspectives

Wuhan, a city of China, is the epicenter for the pandemic outbreak of coronavirus disease-2019 (COVID-19). It has become a severe public health challenge to the world and established a public health emergency of international worry. This infectious disease has pulled down the economy of almost all top developed nations. The coronaviruses (CoVs) known for various epidemics caused time to time. Infectious diseases such as severe acute respiratory syndrome (SARS) and middle east respiratory syndrome (MERS), followed by COVID-19, are all coronaviruses led outbreaks that scourged the history of mankind. CoVs evolved themselves to more infectious, transmissible, and more pandemic with time. To prevent the spread of the SARS-CoV-2, many countries have ordered the complete lockdown to combat the outbreak. This paper briefly discussed the historical background of CoVs and the evolution of human coronaviruses (HCoVs), the case studies and the development of their antiviral medications. The viral infection encountered with present-day challenges and futuristic approaches with the help of nanotechnology to minimize the spread of infectious viruses. The antiviral drugs and their clinical advances, along with herbal medicines for viral inhibition and immunity boosters, are described. Elaboration of tables related to CoVs for the compilation of the literature has been adopted for the better understanding.

Surveillance of endemic human coronaviruses (HCoV-NL63, OC43 and 229E) associated with pneumonia in Kilifi, Kenya

Introduction: Human coronaviruses (HCoVs) circulate endemically in human populations, often with seasonal variation. We describe the long-term patterns of paediatric disease associated with three of these viruses, HCoV-NL63, OC43 and 229E, in coastal Kenya. Methods: Continuous surveillance of pneumonia admissions was conducted at the Kilifi county hospital (KCH) located in the northern coastal region of Kenya. Children aged <5 years admitted to KCH with clinically defined syndromic severe or very severe pneumonia were recruited. Respiratory samples were taken and tested for 15 virus targets, using real-time polymerase chain reaction. Unadjusted odds ratios were used to estimate the association between demographic and clinical characteristics and HCoV positivity. Results: From 2007 to 2019, we observed 11,445 pneumonia admissions, of which 314 (3.9%) tested positive for at least one HCoV type. There were 129 (41.1%) OC43, 99 (31.5%) 229E, 74 (23.6%) NL63 positive cases and 12 (3.8%) cases of HCoV to HCoV coinfection.  Among HCoV positive cases, 47% (n=147) were coinfected with other respiratory virus pathogens. The majority of HCoV cases were among children aged <1 year (66%, n=208), though there was no age-dependence in the proportion testing positive. HCoV-OC43 was predominant of the three HCoV types throughout the surveillance period. Evidence for seasonality was not identified. Conclusions: Overall, 4% of paediatric pneumonia admissions were associated with three endemic HCoVs, with a high proportion of cases co-occurring with another respiratory virus, with no clear seasonal pattern, and with the age-distribution of cases following that of pneumonia admissions (i.e. highest in infants). These observations suggest, at most, a small severe disease contribution of endemic HCoVs in this tropical setting and offer insight into the potential future burden and epidemiological characteristics of SARS-CoV-2.

Transmission and evolutionary dynamics of human coronavirus OC43 strains in coastal Kenya investigated by partial spike sequence analysis, 2015-16

Human coronavirus OC43 (HCoV-OC43) is a major contributor to seasonal outbreaks of acute respiratory illness (ARI). The origins of locally circulating HCoV-OC43 strains and characteristics of their genetic diversity are unknown for most settings despite significance to effective HCoV control strategies. Between December 2015 and June 2016, we undertook ARI surveillance in coastal Kenya in nine outpatients and one inpatient health facility (HF). Ninety-two patient samples tested HCoV-OC43 positive and forty (43.5%) were successfully sequenced in spike (S) gene region (2,864 long, ∼70%). Phylogenetic analysis confirmed co-circulation of two distinct HCoV-OC43 clades that closely clustered with genotype G (n = 34, 85%) and genotype H (n = 6, 15%) reference strains. Local viruses within the same clade displayed low genetic diversity yielding identical sequences in multiple HF. Furthermore, the newly sequenced Kenyan viruses showed close phylogenetic relationship to other contemporaneous sampled strains (2015-16) including those originating from distant places (e.g. USA and China). Using a genetic similarity threshold of 99.1 per cent at nucleotide level, the HCoV-OC43 strains sampled globally between 1967 and 2019 fell into nine sequence clusters. Notably, some of these clusters appeared to have become extinct, or occurred only sporadically in a few geographical areas while others persisted globally for multiple years. In conclusion, we found that HCoV-OC43 strains spread rapidly both locally and across the globe with limited genetic evolution in the spike gene. Full-genome sequences that are spatio-temporally representative are required to advance understanding of the transmission pathways of this important human respiratory pathogen.

SARS-CoV-2: fear versus data

SARS-CoV-2, the novel coronavirus from China, is spreading around the world, causing a huge reaction despite its current low incidence outside China and the Far East. Four common coronaviruses are in current circulation and cause millions of cases worldwide. This article compares the incidence and mortality rates of these four common coronaviruses with those of SARS-CoV-2 in Organisation for Economic Co-operation and Development countries. It is concluded that the problem of SARS-CoV-2 is probably being overestimated, as 2.6 million people die of respiratory infections each year compared with less than 4000 deaths for SARS-CoV-2 at the time of writing.

Coronavirus infections: Epidemiological, clinical and immunological features and hypotheses

Coronaviruses (CoVs) are a large family of enveloped, positive-strand RNA viruses. Four human CoVs (HCoVs), the non-severe acute respiratory syndrome (SARS)-like HCoVs (namely HCoV 229E, NL63, OC43, and HKU1), are globally endemic and account for a substantial fraction of upper respiratory tract infections. Non-SARS-like CoV can occasionally produce severe diseases in frail subjects but do not cause any major (fatal) epidemics. In contrast, SARS like CoVs (namely SARS-CoV and Middle-East respiratory syndrome coronavirus, MERS-CoV) can cause intense short-lived fatal outbreaks. The current epidemic caused by the highly contagious SARS-CoV-2 and its rapid spread globally is of major concern. There is scanty knowledge on the actual pandemic potential of this new SARS-like virus. It might be speculated that SARS-CoV-2 epidemic is grossly underdiagnosed and that the infection is silently spreading across the globe with two consequences: (i) clusters of severe infections among frail subjects could haphazardly occur linked to unrecognized index cases; (ii) the current epidemic could naturally fall into a low-level endemic phase when a significant number of subjects will have developed immunity. Understanding the role of paucisymptomatic subjects and stratifying patients according to the risk of developing severe clinical presentations is pivotal for implementing reasonable measures to contain the infection and to reduce its mortality. Whilst the future evolution of this epidemic remains unpredictable, classic public health strategies must follow rational patterns. The emergence of yet another global epidemic underscores the permanent challenges that infectious diseases pose and underscores the need for global cooperation and preparedness, even during inter-epidemic periods.

Incidence, significance, and persistence of human coronavirus infection in hematopoietic stem cell transplant recipients

Hematopoietic stem cell transplant (HSCT) recipients are at increased risk of respiratory viral infections and their associated complications. Unlike other respiratory viruses, little is known about the clinical significance of human coronavirus infection (HCoV) in this population. We retrospectively identified all HSCT recipients who were transplanted between May 2013 and June 2017 at our institution and characterized the cumulative incidence of post-transplant HCoV infection. Of 678 patients who underwent HSCT during the study period, 112 (17%) developed HCoV infection, making HCoV the fourth most common respiratory viral infection. Thirty-four (30%) HCoV-infected patients progressed to proven or probable lower respiratory tract infection (LRTI). Age ≥50, graft-versus-host disease, corticosteroids, hypoalbuminemia, and inpatient status at the time of infection were independently associated with progression to LRTI. Twenty-seven (59%) patients who underwent repeat NP swab had persistent viral shedding for ≥21 days, with a median duration of 4 weeks of viral shedding. We conclude that HCoV is common and clinically significant in HSCT recipients, with nearly one-third of patients progressing to proven or probable LRTI. Evaluating for LRTI risk factors found in this study may identify patients who require closer surveillance and aggressive supportive care when infected with HCoV.

Human coronavirus circulation in the United States 2014-2017

BACKGROUND

Human coronaviruses (HCoVs) -OC43, -229E, -NL63 and -HKU1 cause upper and lower respiratory tract infections. HCoVs are globally distributed and the predominant species may vary by region or year. Prior studies have shown seasonal patterns of HCoV species and annual variation in species prevalence but national circulation patterns in the US have not yet been described.

OBJECTIVES

To describe circulation patterns of HCoVs -OC43, -229E, -NL63 and -HKU1 in the US.

STUDY DESIGN

We reviewed real-time reverse transcription polymerase chain reaction (rRT-PCR) test results for HCoV-OC43, -229E, -NL63 and -HKU1 reported to The National Respiratory and Enteric Virus Surveillance System (NREVSS) by U.S. laboratories from July 2014-June 2017. We calculated the total number of tests and percent positive by week. For a subset of HCoV positive submissions with age and sex of the patient available, we tested for differences in age and sex across the four HCoV species using Chi Square and Kruskal Wallace tests.

RESULTS

117 laboratories reported 854,575 HCoV tests; 2.2% were positive for HCoV-OC43, 1.0% for HCoV-NL63, 0.8% for HCoV-229E, and 0.6% for HCoV-HKU1. The percentage of positive tests peaked during December - March each year. No significant differences in sex were seen across species, although a significant difference in age distribution was noted.

CONCLUSIONS

Common HCoVs may have annual peaks of circulation in winter months in the US, and individual HCoVs may show variable circulation from year to year. Different HCoV species may be detected more frequently in different age groups. Further years of data are needed to better understand patterns of activity for HCoVs.

Prevalence and genetic diversity analysis of human coronaviruses among cross-border children

Background

More than a decade after the outbreak of human coronaviruses (HCoVs) SARS in Guangdong province and Hong Kong SAR of China in 2002, there is still no reoccurrence, but the evolution and recombination of the coronaviruses in this region are still unknown. Therefore, surveillance on the prevalence and the virus variation of HCoVs circulation in this region is conducted.

Methods

A total of 3298 nasopharyngeal swabs samples were collected from cross-border children (<6 years, crossing border between Southern China and Hong Kong SAR) showing symptoms of respiratory tract infection, such as fever (body temperature > 37.5 °C), from 2014 May to 2015 Dec. Viral nucleic acids were analyzed and sequenced to study the prevalence and genetic diversity of the four human coronaviruses. The statistical significance of the data was evaluated with Fisher chi-square test.

Results

78 (2.37%; 95%CI 1.8-2.8%) out of 3298 nasopharyngeal swabs specimens were found to be positive for OC43 (36;1.09%), HKU1 (34; 1.03%), NL63 (6; 0.18%) and 229E (2;0.01%). None of SARS or MERS was detected. The HCoVs predominant circulating season was in transition of winter to spring, especially January and February and NL63 detected only in summer and fall. Complex population with an abundant genetic diversity of coronaviruses was circulating and they shared homology with the published strains (99-100%). Besides, phylogenetic evolutionary analysis indicated that OC43 coronaviruses were clustered into three clades (B,D,E), HKU1 clustered into two clades(A,B) and NL63 clustered into two clades(A,B). Moreover, several novel mutations including nucleotides substitution and the insertion of spike of the glycoprotein on the viral surface were discovered.

Conclusions

The detection rate and epidemic trend of coronaviruses were stable and no obvious fluctuations were found. The detected coronaviruses shared a conserved gene sequences in S and RdRp. However, mutants of the epidemic strains were detected, suggesting continuous monitoring of the human coronaviruses is in need among cross-border children, who are more likely to get infected and transmit the viruses across the border easily, in addition to the general public.

Epidemiologic and Clinical Characteristics of Coronavirus and Bocavirus Respiratory Infections after Allogeneic Stem Cell Transplantation: A Prospective Single-Center Study

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Human coronavirus are common after allogeneic stem cell transplantation and can progress to LRTDs, and in some cases this leads to hospitalization and requires supportive care.

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Human bocavirus are quite rare after allogeneic stem cell transplantation and are commonly detected in conjunction with other viral co-pathogens.

Epidemiologic data about coronaviruses (CoVs) and human bocavirus (HBoV) in the setting of allogeneic hematopoietic stem cell transplantation (allo-HSCT) are scarce. We conducted a prospective longitudinal study on respiratory viral infections (RVIs) in allo-HSCT recipients with respiratory symptoms from December 2013 until June 2016. Respiratory virus in upper and/or lower respiratory tract (URT and LRT) specimens were tested using Luminex xTAG RVP Fast v1 assay. Seventy-nine consecutive allo-HSCT recipients developed a total of 192 virologically documented RVI episodes over 30 months. The median follow-up after RVI was 388 days (range, 5 to 923). CoV or HBoV was detected in 27 of 192 episodes (14%); 18 of 79 recipients (23%) developed a total of 21 CoV RVI episodes, whereas 6 recipients (8%) had 1 HBoV RVI episode each. Fourteen CoV RVI episodes were limited to the URT, whereas 7 affected the LRT. Co-pathogens were detected in 8 (38%) CoV cases. Type OC43 CoV was the dominant type (48%) followed by NL63 (24%), KHU1 (19%), and 229E (9%); the CoV hospitalization rate was 19%, whereas mortality was 5% (1 patient without any other microbiologic documentation). Among the 6 recipients with HBoV (3%), only 1 had LRT involvement and no one died from respiratory failure. In 5 cases (83%) HBoV was detected along with other viral co-pathogens. CoV RVIs are common after allo-HSCT, and in a significant proportion of cases CoV progressed to LRT and showed moderate to severe clinical features. In contrast, HBoV RVIs were rare and mostly presented in the context of co-infections.