Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR

Early Phylogenetic Diversification of SARS-CoV-2: Determination of Variants and the Effect on Epidemiology, Immunology, and Diagnostics

The phylogenetic clustering of 95 SARS-CoV-2 sequences from the first 3 months of the pandemic reveals insights into the early evolution of the virus and gives first indications of how the variants are globally distributed. Variants might become a challenge in terms of diagnostics, immunology, and effectiveness of drugs. All available whole genome sequence data from the NCBI database (March 16, 2020) were phylogenetically analyzed, and gene prediction as well as analysis of selected variants were performed. Antigenic regions and the secondary protein structure were predicted for selected variants. While some clusters are presenting the same variant with 100% identical bases, other SARS-CoV-2 lineages show a beginning diversification and phylogenetic clustering due to base substitutions and deletions in the genomes. First molecular epidemiological investigations are possible with the results by adding metadata as travelling history to the presented data. The advantage of variants in source tracing can be a challenge in terms of virulence, immune response, and immunological memory. Variants of viruses often show differences in virulence or antigenicity. This must also be considered in decisions like herd immunity. Diagnostic methods might not work if the variations or deletions are in target regions for the detection of the pathogen. One base substitution was detected in a primer binding site.

Clinical Evaluation of the cobas SARS-CoV-2 Test and a Diagnostic Platform Switch during 48 Hours in the Midst of the COVID-19 Pandemic

Laboratories are currently witnessing extraordinary demand globally for sampling devices, reagents, consumables, and diagnostic instruments needed for timely diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To meet diagnostic needs as the pandemic grows, the U.S. Food and Drug Administration (FDA) recently granted several commercial SARS-CoV-2 tests Emergency Use Authorization (EUA), but manufacturer-independent evaluation data are scarce. We performed the first manufacturer-independent evaluation of the fully automated sample-to-result two-target test cobas 6800 SARS-CoV-2 (cobas) (Roche Molecular Systems, Branchburg, NJ), which received U.

Laboratories are currently witnessing extraordinary demand globally for sampling devices, reagents, consumables, and diagnostic instruments needed for timely diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To meet diagnostic needs as the pandemic grows, the U.S. Food and Drug Administration (FDA) recently granted several commercial SARS-CoV-2 tests Emergency Use Authorization (EUA), but manufacturer-independent evaluation data are scarce. We performed the first manufacturer-independent evaluation of the fully automated sample-to-result two-target test cobas 6800 SARS-CoV-2 (cobas) (Roche Molecular Systems, Branchburg, NJ), which received U.S. FDA EUA on 12 March 2020. The comparator was a standardized 3-h SARS-CoV-2 protocol, consisting of RNA extraction using an automated portable instrument, followed by a two-target reverse transcription real-time PCR (RT-PCR), which our laboratory has routinely used since January 2020 [V. M. Corman, O. Landt, M. Kaiser, R. Molenkamp, et al., Euro Surveill 25(3):pii=2000045, 2020, https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045]. cobas and the comparator showed overall agreement of 98.1% and a kappa value of 0.95 on an in-house validation panel consisting of 217 well-characterized retrospective samples. Immediate prospective head-to-head comparative evaluation followed on 502 samples, and the diagnostic approaches showed overall agreement of 99.6% and a kappa value of 0.98. A good correlation (r² = 0.96) between cycle threshold values for SARS-CoV-2-specific targets obtained by cobas and the comparator was observed. Our results showed that cobas is a reliable assay for qualitative detection of SARS-CoV-2 in nasopharyngeal swab samples collected in the Universal Transport Medium System (UTM-RT) (Copan, Brescia, Italy). Under the extraordinary circumstances that laboratories are facing worldwide, a safe diagnostic platform switch is feasible in only 48 h and in the midst of the COVID-19 pandemic if carefully planned and executed.

Laboratory Diagnosis of COVID-19: Current Issues and Challenges

The COVID-19 outbreak has had a major impact on clinical microbiology laboratories in the past several months. This commentary covers current issues and challenges for the laboratory diagnosis of infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the preanalytical stage, collecting the proper respiratory tract specimen at the right time from the right anatomic site is essential for a prompt and accurate molecular diagnosis of COVID-19. Appropriate measures are required to keep laboratory staff safe while producing reliable test results.

The COVID-19 outbreak has had a major impact on clinical microbiology laboratories in the past several months. This commentary covers current issues and challenges for the laboratory diagnosis of infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the preanalytical stage, collecting the proper respiratory tract specimen at the right time from the right anatomic site is essential for a prompt and accurate molecular diagnosis of COVID-19. Appropriate measures are required to keep laboratory staff safe while producing reliable test results. In the analytic stage, real-time reverse transcription-PCR (RT-PCR) assays remain the molecular test of choice for the etiologic diagnosis of SARS-CoV-2 infection while antibody-based techniques are being introduced as supplemental tools. In the postanalytical stage, testing results should be carefully interpreted using both molecular and serological findings. Finally, random-access, integrated devices available at the point of care with scalable capacities will facilitate the rapid and accurate diagnosis and monitoring of SARS-CoV-2 infections and greatly assist in the control of this outbreak.

Comparative Performance of SARS-CoV-2 Detection Assays Using Seven Different Primer-Probe Sets and One Assay Kit

Nearly 400,000 people worldwide are known to have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) beginning in December 2019. The virus has now spread to over 168 countries including the United States, where the first cluster of cases was observed in the Seattle metropolitan area in Washington. Given the rapid increase in the number of cases in many localities, the availability of accurate, high-throughput SARS-CoV-2 testing is vital to efforts to manage the current public health crisis. In the course of optimizing SARS-CoV-2 testing performed by the University of Washington Clinical Virology Lab (UW Virology Lab), we evaluated assays using seven different primer-probe sets and one assay kit. We found that the most sensitive assays were those that used the E-gene primer-probe set described by Corman et al. (V. M. Corman, O. Landt, M. Kaiser, R. Molenkamp, et al., Euro Surveill 25:2000045, 2020, https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045) and the N2 set developed by the CDC (Division of Viral Diseases, Centers for Disease Control and Prevention, 2020, https://www.cdc.gov/coronavirus/2019-ncov/downloads/rt-pcr-panel-primer-probes.pdf). All assays tested were found to be highly specific for SARS-CoV-2, with no cross-reactivity with other respiratory viruses observed in our analyses regardless of the primer-probe set or kit used. These results will provide valuable information to other clinical laboratories who are actively developing SARS-CoV-2 testing protocols at a time when increased testing capacity is urgently needed worldwide.

Dual-Functional Plasmonic Photothermal Biosensors for Highly Accurate Severe Acute Respiratory Syndrome Coronavirus 2 Detection

The ongoing outbreak of the novel coronavirus disease (COVID-19) has spread globally and poses a threat to public health in more than 200 countries. Reliable laboratory diagnosis of the disease has been one of the foremost priorities for promoting public health interventions. The routinely used reverse transcription polymerase chain reaction (RT-PCR) is currently the reference method for COVID-19 diagnosis. However, it also reported a number of false-positive or -negative cases, especially in the early stages of the novel virus outbreak. In this work, a dual-functional plasmonic biosensor combining the plasmonic photothermal (PPT) effect and localized surface plasmon resonance (LSPR) sensing transduction provides an alternative and promising solution for the clinical COVID-19 diagnosis. The two-dimensional gold nanoislands (AuNIs) functionalized with complementary DNA receptors can perform a sensitive detection of the selected sequences from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through nucleic acid hybridization. For better sensing performance, the thermoplasmonic heat is generated on the same AuNIs chip when illuminated at their plasmonic resonance frequency. The localized PPT heat is capable to elevate the in situ hybridization temperature and facilitate the accurate discrimination of two similar gene sequences. Our dual-functional LSPR biosensor exhibits a high sensitivity toward the selected SARS-CoV-2 sequences with a lower detection limit down to the concentration of 0.22 pM and allows precise detection of the specific target in a multigene mixture. This study gains insight into the thermoplasmonic enhancement and its applicability in the nucleic acid tests and viral disease diagnosis.

Dual-Functional Plasmonic Photothermal Biosensors for Highly Accurate Severe Acute Respiratory Syndrome Coronavirus 2 Detection

The ongoing outbreak of the novel coronavirus disease (COVID-19) has spread globally and poses a threat to public health in more than 200 countries. Reliable laboratory diagnosis of the disease has been one of the foremost priorities for promoting public health interventions. The routinely used reverse transcription polymerase chain reaction (RT-PCR) is currently the reference method for COVID-19 diagnosis. However, it also reported a number of false-positive or -negative cases, especially in the early stages of the novel virus outbreak. In this work, a dual-functional plasmonic biosensor combining the plasmonic photothermal (PPT) effect and localized surface plasmon resonance (LSPR) sensing transduction provides an alternative and promising solution for the clinical COVID-19 diagnosis. The two-dimensional gold nanoislands (AuNIs) functionalized with complementary DNA receptors can perform a sensitive detection of the selected sequences from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through nucleic acid hybridization. For better sensing performance, the thermoplasmonic heat is generated on the same AuNIs chip when illuminated at their plasmonic resonance frequency. The localized PPT heat is capable to elevate the in situ hybridization temperature and facilitate the accurate discrimination of two similar gene sequences. Our dual-functional LSPR biosensor exhibits a high sensitivity toward the selected SARS-CoV-2 sequences with a lower detection limit down to the concentration of 0.22 pM and allows precise detection of the specific target in a multigene mixture. This study gains insight into the thermoplasmonic enhancement and its applicability in the nucleic acid tests and viral disease diagnosis.

Clinical Significance of a High SARS-CoV-2 Viral Load in the Saliva

BACKGROUND

Patients with coronavirus disease 2019 (COVID-19) can unknowingly spread the virus to several people during the early subclinical period.

METHODS

We evaluated the viral dynamics in various body fluid specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum, and urine specimens, of two patients with COVID-19 from hospital day 1 to 9. Additional samples of the saliva were taken at 1 hour, 2 hours, and 4 hours after using a chlorhexidine mouthwash. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was determined by real-time reverse transcriptase polymerase chain reaction (rRT-PCR).

RESULTS

SARS-CoV-2 was detected from all the five specimens of both patients by rRT-PCR. The viral load was the highest in the nasopharynx (patient 1 = 8.41 log₁₀ copies/mL; patient 2 = 7.49 log₁₀ copies/mL), but it was also remarkably high in the saliva (patient 1 = 6.63 log₁₀ copies/mL; patient 2 = 7.10 log₁₀ copies/mL). SARS-CoV-2 was detected up to hospital day 6 (illness day 9 for patient 2) from the saliva of both patients. The viral load in the saliva decreased transiently for 2 hours after using the chlorhexidine mouthwash.

CONCLUSION

SARS-CoV-2 viral load was consistently high in the saliva; it was relatively higher than that in the oropharynx during the early stage of COVID-19. Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.

Clinical Significance of a High SARS-CoV-2 Viral Load in the Saliva

BACKGROUND

Patients with coronavirus disease 2019 (COVID-19) can unknowingly spread the virus to several people during the early subclinical period.

METHODS

We evaluated the viral dynamics in various body fluid specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum, and urine specimens, of two patients with COVID-19 from hospital day 1 to 9. Additional samples of the saliva were taken at 1 hour, 2 hours, and 4 hours after using a chlorhexidine mouthwash. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was determined by real-time reverse transcriptase polymerase chain reaction (rRT-PCR).

RESULTS

SARS-CoV-2 was detected from all the five specimens of both patients by rRT-PCR. The viral load was the highest in the nasopharynx (patient 1 = 8.41 log₁₀ copies/mL; patient 2 = 7.49 log₁₀ copies/mL), but it was also remarkably high in the saliva (patient 1 = 6.63 log₁₀ copies/mL; patient 2 = 7.10 log₁₀ copies/mL). SARS-CoV-2 was detected up to hospital day 6 (illness day 9 for patient 2) from the saliva of both patients. The viral load in the saliva decreased transiently for 2 hours after using the chlorhexidine mouthwash.

CONCLUSION

SARS-CoV-2 viral load was consistently high in the saliva; it was relatively higher than that in the oropharynx during the early stage of COVID-19. Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.

[Diagnostic efficacy of three test kits for SARS-CoV-2 nucleic acid detection]

OBJECTIVE

To compare the diagnostic efficacy among three RT-PCR test kits for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid detection.

METHODS

The throat swab samples from 40 hospitalized patients clinically diagnosed as coronavirus disease 2019 (COVID-19) and 16 hospitalized non-COVID-19 patients were recruited. The SARS-CoV-2 nucleic acid was detected in throat swab samples with RT-PCR test kits from Sansure Biotech ("Sansure" for short), Jiangsu Bioperfectus Technologies ("Bioperfectus" for short) and BGI Genomics ("BGI" for short). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value were analyzed. The viral nucleic acid was extracted from the throat swab samples by one-step cleavage and magnetic bead methods, and the efficacy of two extraction methods was also compared. The results of magnetic bead method for nucleic acid extraction by two different extractors (Sansure Natch CS S12C Fully Automated Nucleic Acid Extraction System vs. Tianlong NP968-C Nucleic Acid Extractor) were also compared.

RESULTS

The sensitivity, specificity, PPV, NPV and kappa value were 95.00%, 87.50%, 95.00%, 87.50%and 0.825 for Sansure kit; 90.00%, 87.50%, 94.74%, 77.78%and 0.747 for the Bioperfectus kit, and 82.50%, 81.25%, 91.67%, 65.00%and 0.593 for the BGI kit, respectively. The positive, negative and total coincident rates and kappa value of viral nucleic acid detection results using the samples extracted by one-step cleavage and magnetic bead methods were 95.24%, 100.00%, 96.43%and 0.909, respectively, but the one-step cleavage method took only 25 min, while the magnetic bead method required 180 min. The positive, negative and total coincident rates and kappa value of viral nucleic acid detection results using the samples extracted by the two different nucleic acid extractors were 85.00%, 100.00%, 89.29% and 0.764, respectively.

CONCLUSIONS

The detection efficacy for SARS-CoV-2 nucleic acid by the Sansure kit is relatively higher and the one-step cleavage method has advantages of convenient operation and less time consuming.

The Concept of Making On-Chip Thermal Cycler for RT-PCR Using Conjugate Heat Transfer in Diverging Microchannel

Covid-19 is pandemic to which the world is fighting. Various precautionary measures are being imposed all over the world which is affecting the routine life of an individual and also the economy worldwide. Although, a definite vaccine is still not known to medical science but they are able to distinguish Covid-19 from the other types of flu. Presently this is being done by detecting the SARS-CoV-2 virus using RT-PCR technique as recommended by the World Health Organization (WHO) (WHO, Geneva, 2020). Reverse Transcription Polymerase Chain Reaction (RT-PCR) is a nucleic acid amplification test that converts the RNA into DNA and subsequently amplifies the specific DNA targets. This method was already being employed to detect the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) (Emery et al. in Emerg Infect Dis 10(2):311, 2004). The entire process of DNA amplification takes place in three steps: denaturation, annealing, and extension for which the sample is required to be maintained at constant temperatures of 95, 55 and 72 °C, respectively. This article introduces the technology to achieve a constant temperature which can be tweaked to develop on-chip RT-PCR.

What Do We Need to Know to Improve Diagnostic Testing Methods for the 2019 Novel Coronavirus?

There is widespread agreement that reliable, fast, and easy-to-produce diagnostic testing methods that have high sensitivity and specificity are essential for guiding appropriate responses to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak. At the present time, there are important unanswered questions about testing methods for SARS-CoV-2. This review article interprets recent findings related to the principal testing methods used to diagnose SARS-CoV-2, including reverse-transcription polymerase chain reaction (RT-PCR), chest imaging, and immunoassay. We discuss the value and limitations of these approaches and suggest directions for future research that can advance the understanding of diagnostic methods. Addressing areas of uncertainty will improve clinical outcomes and allow more effective policies to be implemented to control the disease.

Estimation of the number of blood donors during the COVID-19 incubation period across China and analysis of prevention and control measures for blood transfusion transmission

BACKGROUND

The aim of this study was to estimate the number of blood donors during the COVID‐19 incubation period across China.

STUDY DESIGN AND METHODS

In this study, we developed a predictive model to estimate the number of blood donors during the COVID‐19 incubation period among 34 provincial regions in China. Our main assumption was that blood donors of all ages in different regions have a stable blood donation intention and the same infection risk.

RESULTS

First, we estimated the number of blood donors during the COVID‐19 incubation period in Wuhan city, Hubei Province, and China, from December 31, 2019 to March 17, 2020. Second, we compared the number of blood donors during the COVID‐19 incubation period in all provinces across China. In addition, we found that if all RBCs, plasma, and cryoprecipitation were stored in isolation until the 14th day, the potential risk of SARS‐CoV‐2 transmission through blood transfusion was reduced by at least 65.77% after the blood donor safely passed the COVID‐19 incubation period. Moreover, if the detection of SARS‐CoV‐2 RNA was carried out on all platelets, the potential risk would be reduced by 77.48%.

CONCLUSIONS

Although the risk is low, with the rapid spread of the COVID‐19 and the appearance of alarmingly high infectivity and a high fatality rate, appropriate measures should be taken by health departments to ensure the safety of clinical blood.

New Insights of Emerging SARS-CoV-2: Epidemiology, Etiology, Clinical Features, Clinical Treatment, and Prevention

Since the first reports that the novel coronavirus was showing human-to-human transmission characteristics and asymptomatic cases, the number of patients with associated pneumonia has continued to rise and the epidemic has grown. It now threatens the health and lives of people across the world. The governments of many countries have attached great importance to the prevention of SARS-CoV-2, via research into the etiology and epidemiology of this newly emerged disease. Clinical signs, treatment, and prevention characteristics of the novel coronavirus pneumonia have been receiving attention worldwide, especially from medical personnel. However, owing to the different experimental methods, sample sizes, sample sources, and research perspectives of various studies, results have been inconsistent, or relate to an isolated aspect of the virus or the disease it causes. Currently, systematic summary data on the novel coronavirus are limited. This review combines experimental and clinical evidence into a systematic analysis and summary of the current progress of research into SARS-CoV-2, from multiple perspectives, with the aim of gaining a better overall understanding of the disease. Our report provides important information for current clinicians, for the prevention and treatment of COVID-19 pneumonia.

Estandarización de Emergencia para el Diagnóstico del virus SARS-CoV-2 mediante la Reacción en Cadena de la Polimerasa de Transcripción Reversa en Tiempo Real (RT-PCR) en situación de pandemia de COVID-19

Ante la pandemia del coronavirus emergente SARS-CoV-2 (Coronavirus 2 relacionado con el Síndrome Respiratorio agudo severo), es necesaria la estandarización precisa del diagnóstico hospitalario para reducir el tiempo de respuesta en la confirmación de un caso de sospecha. Por esta razón el diagnóstico de laboratorio es una prioridad de los sistemas de salud pública. En la provincia de Soria, de cerca de 100.000 habitantes, con una población muy envejecida, un índice de mortalidad por COVID-19 del doble que el observado en España, el único Hospital Santa Bárbara de la red pública es el único centro diagnóstico de SARS-CoV-2. En el Servicio de Microbiología, hemos establecido una robusta metodología diagnóstica para la detección del ARN viral presente en muestras de pacientes infectados mediante la técnica de Reacción en Cadena de la Polimerasa de Transcripción Reversa (RT-PCR) en Tiempo Real, que permiten en aproximadamente 4 horas emitir un informe. Este estudio describe el proceso que podría guiar a Servicios de Microbiología de otros Centros Hospitalarios.

Indirect effects of severe acute respiratory syndrome coronavirus 2 on the kidney in coronavirus disease patients

Among patients hospitalized for novel coronavirus disease (COVID-19), between 10 and 14% develop an acute kidney injury and around half display marked proteinuria and haematuria. Post-mortem analyses of COVID-19 kidney tissue suggest that renal tubular cells and podocytes are affected. Here we report two cases of collapsing glomerulopathy and tubulointerstitial lesions in living COVID-19 patients. Despite our use of sensitive reverse transcription polymerase chain reaction techniques in this study, we failed to detect the virus in blood, urine and kidney tissues. Our observations suggest that these kidney lesions are probably not due to direct infection of the kidney by severe acute respiratory syndrome coronavirus 2.

3CL hydrolase-based multiepitope peptide vaccine against SARS-CoV-2 using immunoinformatics

The present study provides the first multiepitope vaccine construct using the 3CL hydrolase protein of SARS-CoV-2. The coronavirus 3CL hydrolase (Mpro) enzyme is essential for proteolytic maturation of the virus. This study was based on immunoinformatics and structural vaccinology strategies. The design of the multiepitope vaccine was built using helper T-cell and cytotoxic T-cell epitopes from the 3CL hydrolase protein along with an adjuvant to enhance immune response; these are joined to each other by short peptide linkers. The vaccine also carries potential B-cell linear epitope regions, B-cell discontinuous epitopes, and interferon-γ-inducing epitopes. Epitopes of the constructed multiepitope vaccine were found to be antigenic, nonallergic, nontoxic, and covering large human populations worldwide. The vaccine construct was modeled, validated, and refined by different programs to achieve a high-quality three-dimensional structure. The resulting high-quality model was applied for conformational B-cell epitope selection and docking analyses with toll-like receptor-3 for understanding the capability of the vaccine to elicit an immune response. In silico cloning and codon adaptation were also performed with the pET-19b plasmid vector. The designed multiepitope peptide vaccine may prompt the development of a vaccine to control SARS-CoV-2 infection.

Covid-19 in Critically Ill Patients in the Seattle Region - Case Series

BACKGROUND

Community transmission of coronavirus 2019 (Covid-19) was detected in the state of Washington in February 2020.

METHODS

We identified patients from nine Seattle-area hospitals who were admitted to the intensive care unit (ICU) with confirmed infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Clinical data were obtained through review of medical records. The data reported here are those available through March 23, 2020. Each patient had at least 14 days of follow-up.

RESULTS

We identified 24 patients with confirmed Covid-19. The mean (±SD) age of the patients was 64±18 years, 63% were men, and symptoms began 7±4 days before admission. The most common symptoms were cough and shortness of breath; 50% of patients had fever on admission, and 58% had diabetes mellitus. All the patients were admitted for hypoxemic respiratory failure; 75% (18 patients) needed mechanical ventilation. Most of the patients (17) also had hypotension and needed vasopressors. No patient tested positive for influenza A, influenza B, or other respiratory viruses. Half the patients (12) died between ICU day 1 and day 18, including 4 patients who had a do-not-resuscitate order on admission. Of the 12 surviving patients, 5 were discharged home, 4 were discharged from the ICU but remained in the hospital, and 3 continued to receive mechanical ventilation in the ICU.

CONCLUSIONS

During the first 3 weeks of the Covid-19 outbreak in the Seattle area, the most common reasons for admission to the ICU were hypoxemic respiratory failure leading to mechanical ventilation, hypotension requiring vasopressor treatment, or both. Mortality among these critically ill patients was high. (Funded by the National Institutes of Health.).

The laboratory tests and host immunity of COVID-19 patients with different severity of illness

BACKGROUNDThe coronavirus disease 2019 (COVID-19), infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a severe outbreak throughout the world. The host immunity of COVID-19 patients is unknown.METHODSThe routine laboratory tests and host immunity in COVID-19 patients with different severity of illness were compared after patient admission.RESULTSA total of 65 SARS-CoV-2-positive patients were classified as having mild (n = 30), severe (n = 20), and extremely severe (n = 15) illness. Many routine laboratory tests, such as ferritin, lactate dehydrogenase, and D-dimer, were increased in severe and extremely severe patients. The absolute numbers of CD4+ T cells, CD8+ T cells, and B cells were gradually decreased with increased severity of illness. The activation markers such as HLA-DR and CD45RO expressed on CD4+ and CD8+ T cells were increased in severe and extremely severe patients compared with mild patients. The costimulatory molecule CD28 had opposite results. The percentage of natural Tregs was decreased in extremely severe patients. The percentage of IFN-γ-producing CD8+ T cells was increased in both severe and extremely severe patients compared with mild patients. The percentage of IFN-γ-producing CD4+ T cells was increased in extremely severe patients. IL-2R, IL-6, and IL-10 were all increased in extremely severe patients. The activation of DC and B cells was decreased in extremely severe patients.CONCLUSIONThe number and function of T cells are inconsistent in COVID-19 patients. The hyperfunction of CD4+ and CD8+ T cells is associated with the pathogenesis of extremely severe SARS-CoV-2 infection.FUNDINGThis work was funded by the National Mega Project on Major Infectious Disease Prevention (2017ZX10103005-007) and the Fundamental Research Funds for the Central Universities (2019kfyRCPY098).

Low performance of rapid antigen detection test as frontline testing for COVID-19 diagnosis

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Coris COVID-19 Ag Respi-Strip should not be used alone for COVID-19 diagnosis.

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Coris COVID-19 Ag Respi-Strip shows no benefit in reducing the use of RT-qPCR.

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Highest viral load is associated with better antigen detection rates.

Background

Ensuring accurate diagnosis is essential to limit the spread of SARS-CoV-2 and for the clinical management of COVID-19. Although real-time reverse transcription polymerase chain reaction (RT- qPCR) is the current recommended laboratory method to diagnose SARS-CoV-2 acute infection, several factors such as requirement of special equipment and skilled staff limit the use of these time-consuming molecular techniques. Recently, several easy to perform rapid antigen detection tests were developed and recommended in some countries as the first line of diagnostic.

Objectives

The aim of this study was to evaluate the performances of the Coris COVID-19 Ag Respi-Strip test, a rapid immunochromatographic test for the detection of SARS-CoV-2 antigen, in comparison to RT-qPCR.

Results

148 nasopharyngeal swabs were tested. Amongst the 106 positive RT-qPCR samples, 32 were detected by the rapid antigen test, given an overall sensitivity of 30.2%. All the samples detected positive with the antigen rapid test were also positive with RT-qPCR.

Conclusions

Higher viral loads are associated with better antigen detection rates. Unfortunately, the overall poor sensitivity of the COVID-19 Ag Respi-Strip does not allow using it alone as the frontline testing for COVID-19 diagnosis.

Delayed Laboratory Response to COVID-19 Caused by Molecular Diagnostic Contamination

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) created an exceptional situation in which numerous laboratories in Europe simultaneously implemented SARS-CoV-2 diagnostics. These laboratories reported in February 2020 that commercial primer and probe batches for SARS-CoV-2 detection were contaminated with synthetic control material, causing delays of regional testing roll-out in various countries.

Sample Pooling as a Strategy to Detect Community Transmission of SARS-CoV-2

This study describes findings of novel coronavirus testing on pooled nasopharyngeal and bronchoalveolar lavage samples taken from patients who had negative results by routine respiratory virus testing to see if pooling samples could increase testing throughput and efficiency and facilitate early detection of community COVID-19 transmission.

Biological and social aspects of Coronavirus Disease 2019 (COVID-19) related to oral health

The expansion of coronavirus disease 2019 (COVID-19) throughout the world has alarmed all health professionals. Especially in dentistry, there is a growing concern due to it's high virulence and routes of transmission through saliva aerosols. The virus keeps viable on air for at least 3 hours and on plastic and stainless-steel surfaces up to 72 hours. In this sense, dental offices, both in the public and private sectors, are high-risk settings of cross infection among patients, dentists and health professionals in the clinical environment (including hospital's intensive dental care facilities). This manuscript aims to compile current available evidence on prevention strategies for dental professionals. Besides, we briefly describe promising treatment strategies recognized until this moment. The purpose is to clarify dental practitioners about the virus history and microbiology, besides guiding on how to proceed during emergency consultations based on international documents. Dentists should consider that a substantial number of individuals (including children) who do not show any signs and symptoms of COVID-19 may be infected and can disseminate the virus. Currently, there is no effective treatment and fast diagnosis is still a challenge. All elective dental treatments and non-essential procedures should be postponed, keeping only urgent and emergency visits to the dental office. The use of teledentistry (phone calls, text messages) is a very promising tool to keep contact with the patient without being at risk of infection.

SARS-CoV-2 viral load assessment in respiratory samples

Real-time reverse transcriptase polymerase chain reaction (rRTPCR) has been the main method for diagnosis of SARS-CoV-2 infection in the early stages of the COVID-19 pandemic. De-identified results from upper and lower respiratory samples submitted to a reference laboratory demonstrated a positivity rate of 14.9 % (4428 of 29,713 samples tested). Distribution of results by birth year cohort and specimen type suggested general consistency in mean, median and peak values but higher positivity rates in individuals born from 1964 to 1974. Female patients had a significantly lower positivity rate (P < 0.0001), although similar load mean and median values, compared to males. Overall, 15.3 % (676 of 4428 positive results) of positive results had viral loads greater than 8 log10 copies/mL, with occasional samples exceeding 10 log10 copies/mL. These results support quantitative assessment of SARS-CoV-2 viral load in patient testing and efforts to control viral transmission

Antibody Tests in Detecting SARS-CoV-2 Infection: A Meta-Analysis

The emergence of Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 made imperative the need for diagnostic tests that can identify the infection. Although Nucleic Acid Test (NAT) is considered to be the gold standard, serological tests based on antibodies could be very helpful. However, individual studies are usually inconclusive, thus, a comparison of different tests is needed. We performed a systematic review and meta-analysis in PubMed, medRxiv and bioRxiv. We used the bivariate method for meta-analysis of diagnostic tests pooling sensitivities and specificities. We evaluated IgM and IgG tests based on Enzyme-linked immunosorbent assay (ELISA), Chemiluminescence Enzyme Immunoassays (CLIA), Fluorescence Immunoassays (FIA), and the Lateral Flow Immunoassays (LFIA). We identified 38 studies containing data from 7848 individuals. Tests using the S antigen are more sensitive than N antigen-based tests. IgG tests perform better compared to IgM ones and show better sensitivity when the samples were taken longer after the onset of symptoms. Moreover, a combined IgG/IgM test seems to be a better choice in terms of sensitivity than measuring either antibody alone. All methods yield high specificity with some of them (ELISA and LFIA) reaching levels around 99%. ELISA- and CLIA-based methods perform better in terms of sensitivity (90%-94%) followed by LFIA and FIA with sensitivities ranging from 80% to 89%. ELISA tests could be a safer choice at this stage of the pandemic. LFIA tests are more attractive for large seroprevalence studies but show lower sensitivity, and this should be taken into account when designing and performing seroprevalence studies.

Sequence mismatch in PCR probes may mask the COVID-19 detection in Nepal

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Most of the COVID-19 cases in Nepal are in the Southern districts of Nepal bordering India with travel histories to India.

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Very few positive cases of COVID-19 are detected in Nepal which could either be due to early national lockdown.

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Low PCR positivity rates could also be due to inefficiency of the PCR methods.

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Whole genomes of 93 clinical samples from COVID-19 patients were analyzed to find the primer and probe binding sites.

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Mutations in probe binding sites were found which could impact PCR efficiency resulting in false negative results

Potential Presymptomatic Transmission of SARS-CoV-2, Zhejiang Province, China, 2020

We report a 2-family cluster of persons infected with severe acute respiratory syndrome coronavirus 2 in the city of Zhoushan, Zhejiang Province, China, during January 2020. The infections resulted from contact with an infected but potentially presymptomatic traveler from the city of Wuhan in Hubei Province.

Emergency trauma care during the outbreak of corona virus disease 2019 (COVID-19) in China

BACKGROUND

A novel coronavirus pneumonia outbreak began in Wuhan, Hubei Province, in December 2019; the outbreak was caused by a novel coronavirus previously never observed in humans. China has imposed the strictest quarantine and closed management measures in history to control the spread of the disease. However, a high level of evidence to support the surgical management of potential trauma patients during the novel coronavirus outbreak is still lacking. To regulate the emergency treatment of trauma patients during the outbreak, we drafted this paper from a trauma surgeon perspective according to practical experience in Wuhan.

MAIN BODY

The article illustrates the general principles for the triage and evaluation of trauma patients during the outbreak of COVID-19, indications for emergency surgery, and infection prevention and control for medical personnel, providing a practical algorithm for trauma care providers during the outbreak period.

CONCLUSIONS

The measures of emergency trauma care that we have provided can protect the medical personnel involved in emergency care and ensure the timeliness of effective interventions during the outbreak of COVID-19.

Masks and closed-loop ventilators prevent environmental contamination by COVID-19 patients in negative-pressure environments

Herein, we report that nosocomial infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be mitigated by using surgical masks and closed looped ventilation for both non-critical and critical patients. These preventive measures resulted in no viral contamination of surfaces in negative pressure environments.

Developments, Evolution, and Implications of National Diagnostic Criteria for COVID-19 in China

Recently WHO has characterized COVID-19 as a pandemic. Diagnosing the disease accurately and decreasing misdiagnoses and missed diagnoses is very important for management. Therefore, we have analyzed the seven versions of China's national guidelines to examine how the diagnostic criteria roadmap has developed and evolved, in order to share our experience worldwide. In this article, we present the developments from the first to seventh versions, involving changes of case classification, changes to "suspected case," changes in "confirmed case," changes in clinical classifications, changes in "severe case," and unchanged criteria. We have also discussed the reasons and implications for these changes and are looking forward to providing suggestions for worldwide understanding and management of this pandemic. A nucleic acid test is currently accepted as the gold standard method to confirm diagnosis. In addition, imaging examination and epidemiological history should also be considered as auxiliary diagnosis methods.

Coronavirus Disease 2019 (COVID-19) in Neonates and Children From China: A Review

At the end of 2019, a novel coronavirus began to spread in Wuhan, Hubei Province, China. The confirmed cases increased nationwide rapidly, in part due to the increased population mobility during the Chinese Lunar New Year festival. The World Health Organization (WHO) subsequently named the novel coronavirus pneumonia Coronavirus Disease 2019 (COVID-19) and named the virus Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Soon, transmission from person to person was confirmed and the virus spread to many other countries. To date, many cases have been reported in the pediatric age group, most of which were from China. The management and treatment strategies have also been improved, which we believe would be helpful to pediatric series in other countries as well. However, the characteristics of neonatal and childhood infection still have not been evaluated in detail. This review summarizes the current understanding of SARS-CoV-2 infection in neonates and children from January 24 to May 1, as an experience from China.

Update for Anaesthetists on Clinical Features of COVID-19 Patients and Relevant Management

When preparing for the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the coronavirus infection disease (COVID-19) questions arose regarding various aspects concerning the anaesthetist. When reviewing the literature it became obvious that keeping up-to-date with all relevant publications is almost impossible. We searched for and summarised clinically relevant topics that could help making clinical decisions. This is a subjective analysis of literature concerning specific topics raised in our daily practice (e.g., clinical features of COVID-19 patients; ventilation of the critically ill COVID-19 patient; diagnostic of infection with SARS-CoV-2; stability of the virus; Covid-19 in specific patient populations, e.g., paediatrics, immunosuppressed patients, patients with hypertension, diabetes mellitus, kidney or liver disease; co-medication with non-steroidal anti-inflammatory drugs (NSAIDs); antiviral treatment) and we believe that these answers help colleagues in clinical decision-making. With ongoing treatment of severely ill COVID-19 patients other questions will come up. While respective guidelines on these topics will serve clinicians in clinical practice, regularly updating all guidelines concerning COVID-19 will be a necessary, although challenging task in the upcoming weeks and months. All recommendations during the current extremely rapid development of knowledge must be evaluated on a daily basis, as suggestions made today may be out-dated with the new evidence available tomorrow.

Risk factors for SARS-CoV-2 among patients in the Oxford Royal College of General Practitioners Research and Surveillance Centre primary care network: a cross-sectional study

BACKGROUND

There are few primary care studies of the COVID-19 pandemic. We aimed to identify demographic and clinical risk factors for testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within the Oxford Royal College of General Practitioners (RCGP) Research and Surveillance Centre primary care network.

METHODS

We analysed routinely collected, pseudonymised data for patients in the RCGP Research and Surveillance Centre primary care sentinel network who were tested for SARS-CoV-2 between Jan 28 and April 4, 2020. We used multivariable logistic regression models with multiple imputation to identify risk factors for positive SARS-CoV-2 tests within this surveillance network.

FINDINGS

We identified 3802 SARS-CoV-2 test results, of which 587 were positive. In multivariable analysis, male sex was independently associated with testing positive for SARS-CoV-2 (296 [18·4%] of 1612 men vs 291 [13·3%] of 2190 women; adjusted odds ratio [OR] 1·55, 95% CI 1·27-1·89). Adults were at increased risk of testing positive for SARS-CoV-2 compared with children, and people aged 40-64 years were at greatest risk in the multivariable model (243 [18·5%] of 1316 adults aged 40-64 years vs 23 [4·6%] of 499 children; adjusted OR 5·36, 95% CI 3·28-8·76). Compared with white people, the adjusted odds of a positive test were greater in black people (388 [15·5%] of 2497 white people vs 36 [62·1%] of 58 black people; adjusted OR 4·75, 95% CI 2·65-8·51). People living in urban areas versus rural areas (476 [26·2%] of 1816 in urban areas vs 111 [5·6%] of 1986 in rural areas; adjusted OR 4·59, 95% CI 3·57-5·90) and in more deprived areas (197 [29·5%] of 668 in most deprived vs 143 [7·7%] of 1855 in least deprived; adjusted OR 2·03, 95% CI 1·51-2·71) were more likely to test positive. People with chronic kidney disease were more likely to test positive in the adjusted analysis (68 [32·9%] of 207 with chronic kidney disease vs 519 [14·4%] of 3595 without; adjusted OR 1·91, 95% CI 1·31-2·78), but there was no significant association with other chronic conditions in that analysis. We found increased odds of a positive test among people who are obese (142 [20·9%] of 680 people with obesity vs 171 [13·2%] of 1296 normal-weight people; adjusted OR 1·41, 95% CI 1·04-1·91). Notably, active smoking was linked with decreased odds of a positive test result (47 [11·4%] of 413 active smokers vs 201 [17·9%] of 1125 non-smokers; adjusted OR 0·49, 95% CI 0·34-0·71).

INTERPRETATION

A positive SARS-CoV-2 test result in this primary care cohort was associated with similar risk factors as observed for severe outcomes of COVID-19 in hospital settings, except for smoking. We provide evidence of potential sociodemographic factors associated with a positive test, including deprivation, population density, ethnicity, and chronic kidney disease.

FUNDING

Wellcome Trust.

Multiple-centre clinical evaluation of an ultrafast single-tube assay for SARS-CoV-2 RNA

OBJECTIVE

To evaluate the performance of an ultrafast single-tube nucleic acid isothermal amplification detection assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA using clinical samples from multiple centres.

METHODS

A reverse transcription recombinase-aided amplification (RT-RAA) assay for SARS-CoV-2 was conducted within 15 minutes at 39°C with portable instruments after addition of extracted RNA. The clinical performance of RT-RAA assay was evaluated using 947 clinical samples from five institutions in four regions of China; approved commercial fluorescence quantitative real-time PCR (qRT-PCR) kits were used for parallel detection. The sensitivity and specificity of RT-RAA were compared and analysed.

RESULTS

The RT-RAA test results of 926 samples were consistent with those of qRT-PCR (330 were positive, 596 negative); 21 results were inconsistent. The sensitivity and specificity of RT-RAA was 97.63% (330/338, 95% confidence interval (CI) 95.21 to 98.90) and 97.87% (596/609, 95% CI 96.28 to 98.81) respectively. The positive and negative predictive values were 96.21% (330/343, 95% CI 93.45 to 97.88) and 98.68% (596/604, 95% CI 97.30 to 99.38) respectively. The total coincidence rate was 97.78% (926/947, 95% CI 96.80 to 98.70), and the kappa was 0.952 (p < 0.05).

CONCLUSIONS

With comparable sensitivity and specificity to the commercial qRT-PCR kits, RT-RAA assay for SARS-CoV-2 exhibited the distinctive advantages of simplicity and rapidity in terms of operation and turnaround time.

Preparedness of European diagnostic microbiology labs for detection of SARS-CoV-2, March 2020

BACKGROUND

To track the European spread of SARS-CoV-2, decentralized testing became necessary and test capacity needed to be expanded outside reference laboratories rapidly.

METHODS

We assessed via an online questionnaire the preparedness of European hospital laboratories for detection of SARS-CoV-2 and listed the main drawbacks for implementation.

RESULTS

Forty-five percent of the surveyed labs had a test in place by March 26th which is well into the first wave of the pandemic in most countries.

CONCLUSIONS

The main implementation barriers for introduction of a SARSCoV-2 molecular assay in European diagnostic laboratories were availability of positive controls and a specificity panel.

Infection of dogs with SARS-CoV-2

SARS-CoV-2 emerged in Wuhan in December 2019 and caused the pandemic respiratory disease, COVID-19.^1,2 In 2003, the closely related SARS-CoV had been detected in domestic cats and a dog.³ However, little is known about the susceptibility of domestic pet mammals to SARS-CoV-2. Two of 15 dogs from households with confirmed human cases of COVID-19 in Hong Kong SAR were found to be infected using quantitative RT-PCR, serology, sequencing the viral genome, and in one dog, virus isolation. SARS-CoV-2 RNA was detected in a 17 year-old neutered male Pomeranian from five nasal swabs collected over a 13 day period. A 2.5 yo male German Shepherd dog had SARS CoV-2 RNA on two occasions and virus was isolated from nasal and oral swabs. Both dogs had antibody responses detected using plaque reduction neutralisation assays. Viral genetic sequences of viruses from the two dogs were identical to the virus detected in the respective human cases. The animals remained asymptomatic during quarantine. The evidence suggests that these are instances of human-to-animal transmission of SARS-CoV-2. It is unclear whether infected dogs can transmit the virus to other animals or back to humans.

Research on the urban resilience evaluation with hybrid multiple attribute TOPSIS method: an example in China

Cities are important barriers to protect people's lives and property in the face of natural disasters, economic fluctuations and epidemic diseases. The evaluation of urban resilience is a hybrid multiple attribute group decision-making problem involving both crisp and fuzzy indicators. In order to evaluate the urban resilience reasonably and quantitatively, an urban resilience evaluation index system is established, including four primary indicators of ecological environment, municipal facilities, economic development and social development, and 28 secondary indicators. An evaluation model based on the theory of intuitionistic fuzzy set and TOPSIS method is proposed. The intuitionistic trapezoidal fuzzy number is used to quantify the fuzzy index and determine the weights of experts. The weight of each index is determined based on the maximizing deviation method. The relevant data of Dalian City from 2013 to 2017 are collected to evaluate the city resilience, and a sensitivity analysis is carried out based on the proposed model. The results may provide insights for the further urban resilience promotion.

ChAdOx1 nCoV-19 vaccination prevents SARS-CoV-2 pneumonia in rhesus macaques

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged in December 20191,2 and is responsible for the COVID-19 pandemic3. Vaccines are an essential countermeasure urgently needed to control the pandemic4. Here, we show that the adenovirus-vectored vaccine ChAdOx1 nCoV-19, encoding the spike protein of SARS-CoV-2, is immunogenic in mice, eliciting a robust humoral and cell-mediated response. This response was not Th2 dominated, as demonstrated by IgG subclass and cytokine expression profiling. A single vaccination with ChAdOx1 nCoV-19 induced a humoral and cellular immune response in rhesus macaques. We observed a significantly reduced viral load in bronchoalveolar lavage fluid and respiratory tract tissue of vaccinated animals challenged with SARS-CoV-2 compared with control animals, and no pneumonia was observed in vaccinated rhesus macaques. Importantly, no evidence of immune-enhanced disease following viral challenge in vaccinated animals was observed. ChAdOx1 nCoV-19 is currently under investigation in a phase I clinical trial. Safety, immunogenicity and efficacy against symptomatic PCR-positive COVID-19 disease will now be assessed in randomised controlled human clinical trials.

Treatment of COVID-19 Patients with Convalescent Plasma in Houston, Texas

BACKGROUND

COVID-19 disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread globally, and no proven treatments are available. Convalescent plasma therapy has been used with varying degrees of success to treat severe microbial infections for more than 100 years.

METHODS

Patients (n=25) with severe and/or life-threatening COVID-19 disease were enrolled at the Houston Methodist hospitals from March 28 to April 14, 2020. Patients were transfused with convalescent plasma obtained from donors with confirmed SARS-CoV-2 infection and had been symptom free for 14 days. The primary study outcome was safety, and the secondary outcome was clinical status at day 14 post-transfusion. Clinical improvement was assessed based on a modified World Health Organization 6-point ordinal scale and laboratory parameters. Viral genome sequencing was performed on donor and recipient strains.

RESULTS

At baseline, all patients were receiving supportive care, including anti-inflammatory and anti-viral treatments, and all patients were on oxygen support. At day 7 post-transfusion with convalescent plasma, nine patients had at least a 1-point improvement in clinical scale, and seven of those were discharged. By day 14 post-transfusion, 19 (76%) patients had at least a 1-point improvement in clinical status and 11 were discharged. No adverse events as a result of plasma transfusion were observed. The whole genome sequencing data did not identify a strain genotype-disease severity correlation.

CONCLUSIONS

The data indicate that administration of convalescent plasma is a safe treatment option for those with severe COVID-19 disease. Randomized, controlled trials are needed to determine its efficacy.

Towards effective diagnostic assays for COVID-19: a review

Countries globally are affected by the COVID-19 pandemic, with nearly two million cases and 120 000 deaths occurring within 4 months of the discovery of the severe acute respiratory syndrome coronavirus-2 in December 2019 in China. Accurate diagnoses of cases is key in managing the pandemic by identification, isolation and treatment of patients and defining the epidemiology of the virus. By mid-January 2020, a scientist from China published the full genome of the virus, which facilitated the development of accurate molecular diagnostic assays. By the end of January 2020, the WHO, in collaboration with laboratories in Asia, Europe and the USA, published several real-time reverse transcriptase PCR (rtRT-PCR) protocols that allowed identification of cases and development of commercial assays. Clinical investigations facilitated development of accurate case definition and guidance for laboratories on the optimum specimens and procedures for diagnoses. Currently, laboratory-based rtRT-PCR is the recommended test for diagnoses of acute cases to ensure patients can be identified and isolated and to facilitate the public health response. However, due to delays in diagnoses, severe shortage of tests and laboratory capacity, point-of-care molecular or antigen tests are becoming more attractive. Although serological tests are not suitable for diagnoses of acute cases, they are important to define epidemiological questions, including attack rate in the population, and to identify immune individuals. This review aimed to summarise the current available information for diagnoses of cases and to aid laboratories and healthcare workers to select the best assays and procedures.