The role of laboratory diagnostics in emerging viral infections: the example of the Middle East respiratory syndrome epidemic

An individual level infectious disease model in the presence of uncertainty from multiple, imperfect diagnostic tests

Bayesian compartmental infectious disease models yield important inference on disease transmission by appropriately accounting for the dynamics and uncertainty of infection processes. In addition to estimating transition probabilities and reproductive numbers, these statistical models allow researchers to assess the probability of disease risk and quantify the effectiveness of interventions. These infectious disease models rely on data collected from all individuals classified as positive based on various diagnostic tests. In infectious disease testing, however, such procedures produce both false-positives and false-negatives at varying rates depending on the sensitivity and specificity of the diagnostic tests being used. We propose a novel Bayesian spatio-temporal infectious disease modeling framework that accounts for the additional uncertainty in the diagnostic testing and classification process that provides estimates of the important transmission dynamics of interest to researchers. The method is applied to data on the 2006 mumps epidemic in Iowa, in which over 6,000 suspected mumps cases were tested using a buccal or oral swab specimen, a urine specimen, and/or a blood specimen. Although all procedures are believed to have high specificities, the sensitivities can be low and vary depending on the timing of the test as well as the vaccination status of the individual being tested.

A comparative study of the policy response to COVID-19 in the ASEAN region: A dynamic simulated ARDL approach

The COVID-19 epidemic is the most significant global health disaster of this century and the greatest challenge to humanity since World War II. One of the most important research issues is to determine the effectiveness of measures implemented worldwide to control the spread of the corona virus. A dynamic simulated Autoregressive-Distributed Lag (ARDL) approach was adopted to analyze the policy response to COVID-19 in the ASEAN region using data from February 1, 2020, to November 8, 2021. The results of unit root concluded that the dependent variable is integrated of order one while the independent variables are stationarized at the level or first difference, and the use of a dynamic simulated ARDL technique is appropriate for this paper. The outcomes of the dynamic simulated ARDL model explored that government economic support and debt/contract relief for poor families is substantially important in the fight against COVID-19. The study also explored that closing schools and workplaces, restrictions on gatherings, cancellation of public events, stay at home, closing public transport, restrictions on domestic and international travel are necessary to reduce the spread of COVID-19. Finally, this study explored that public awareness campaigns, testing policy and social distancing significantly decrease the spread of COVID-19. Policy implications such as economic support from the government to help poor families, closing schools and public gatherings during the pandemic, public awareness among the masses, and testing policies must be adopted to reduce the spread of COVID-19. Moreover, the reduction in mortality shows that immunization could be a possible new strategy to combat COVID-19, but the factors responsible for the acceptability of the vaccine must be addressed immediately through public health policies.

Commercially available rapid diagnostic tests for the detection of high priority pathogens: status and challenges

The ongoing COVID-19 pandemic has shown the importance of having analytical devices that allow a simple, fast, and robust detection of pathogens which cause epidemics and pandemics. The information these devices can collect is crucial for health authorities to make effective decisions to contain the disease's advance. The World Health Organization published a list of primary pathogens that have raised concern as potential causes of future pandemics. Unfortunately, there are no rapid diagnostic tests commercially available and approved by the regulatory bodies to detect most of the pathogens listed by the WHO. This report describes these pathogens, the available detection methods, and highlights areas where more attention is needed to produce rapid diagnostic tests for future pandemic surveillance.

RNA Coronaviruses' Outbreaks: Recent Progress on the SARS-CoV-2 Pandemic Diagnostic Tests, Vaccination and Therapeutics

Coronaviruses are RNA-infective viruses that could be considered principal players in universal high-profile outbreaks, namely the Severe Acute Respiratory Syndrome (SARS, 2002-2003), the Middle East Respiratory Syndrome (MERS, 2012) and the continuing novel coronavirus disease (COVID-19, 2019) pandemic. RNA coronaviruses infections raise public health concerns with infections' severity ranging from serious pandemics and highly contagious infections to common influenza episodes. With a wide consensus concerning the seminal role of early detection of the infectious agent on the clinical prognosis, recent technological endeavors have facilitated the rapid, sensitive and specific diagnosis of viral infections. Given that the burst of confirmed cases of the novel coronavirus disease 2019 (COVID-19) are climbing steeply, and we are amid this pandemic, this work will center at the respiratory RNA-viruses outbreaks, including the three coronaviruses-related pandemics, emphasizing on the approved diagnostic approaches, outlining therapeutic clinical trials as well as vaccine candidates. Based on the accumulated data and knowledge on the previous RNA-virus outbreaks, this review aspires to link the current intervention measures against SARS-CoV-2 infection with the previous interventions and to provide a roadmap for any possible future measures.

A computational tool for trend analysis and forecast of the COVID-19 pandemic

Purpose:

This paper proposes a methodology and a computational tool to study the COVID-19 pandemic throughout the world and to perform a trend analysis to assess its local dynamics.

Methods:

Mathematical functions are employed to describe the number of cases and demises in each region and to predict their final numbers, as well as the dates of maximum daily occurrences and the local stabilization date. The model parameters are calibrated using a computational methodology for numerical optimization. Trend analyses are run, allowing to assess the effects of public policies. Easy to interpret metrics over the quality of the fitted curves are provided. Country-wise data from the European Centre for Disease Prevention and Control (ECDC) concerning the daily number of cases and demises around the world are used, as well as detailed data from Johns Hopkins University and from the Brasil.io project describing individually the occurrences in United States counties and in Brazilian states and cities, respectively. U. S. and Brazil were chosen for a more detailed analysis because they are the current focus of the pandemic.

Results:

Illustrative results for different countries, U. S. counties and Brazilian states and cities are presented and discussed.

Conclusion:

The main contributions of this work lie in (i) a straightforward model of the curves to represent the data, which allows automation of the process without requiring interventions from experts; (ii) an innovative approach for trend analysis, whose results provide important information to support authorities in their decision-making process; and (iii) the developed computational tool, which is freely available and allows the user to quickly update the COVID-19 analyses and forecasts for any country, United States county or Brazilian state or city present in the periodic reports from the authorities.

A network-based model to explore the role of testing in the epidemiological control of the COVID-19 pandemic

BACKGROUND

Testing is one of the most effective means to manage the COVID-19 pandemic. However, there is an upper bound on daily testing volume because of limited healthcare staff and working hours, as well as different testing methods, such as random testing and contact-tracking testing. In this study, a network-based epidemic transmission model combined with a testing mechanism was proposed to study the role of testing in epidemic control. The aim of this study was to determine how testing affects the spread of epidemics and the daily testing volume needed to control infectious diseases.

METHODS

We simulated the epidemic spread process on complex networks and introduced testing preferences to describe different testing strategies. Different networks were generated to represent social contact between individuals. An extended susceptible-exposed-infected-recovered (SEIR) epidemic model was adopted to simulate the spread of epidemics in these networks. The model establishes a testing preference of between 0 and 1; the larger the testing preference, the higher the testing priority for people in close contact with confirmed cases.

RESULTS

The numerical simulations revealed that the higher the priority for testing individuals in close contact with confirmed cases, the smaller the infection scale. In addition, the infection peak decreased with an increase in daily testing volume and increased as the testing start time was delayed. We also discovered that when testing and other measures were adopted, the daily testing volume required to keep the infection scale below 5% was reduced by more than 40% even if other measures only reduced individuals' infection probability by 10%. The proposed model was validated using COVID-19 testing data.

CONCLUSIONS

Although testing could effectively inhibit the spread of infectious diseases and epidemics, our results indicated that it requires a huge daily testing volume. Thus, it is highly recommended that testing be adopted in combination with measures such as wearing masks and social distancing to better manage infectious diseases. Our research contributes to understanding the role of testing in epidemic control and provides useful suggestions for the government and individuals in responding to epidemics.

Laboratory verification of an RT-PCR assay for SARS-CoV-2

BACKGROUND

Reverse transcription-polymerase chain reaction (RT-PCR) is an extremely common clinical method for detecting pathogens, particularly for emerging infectious diseases such as the new coronavirus disease (COVID-19). Currently, detection of the RNA from the novel coronavirus SARS-CoV-2 is the gold standard for establishing a COVID-19 diagnosis. This study evaluates the characteristic performance of the analytical system in a clinical laboratory.

METHODS

A commercial SARS-CoV-2 RNA RT-PCR Kit used in a clinical laboratory is assessed based on ISO 15189 verification requirements. A multiple real-time RT-PCR assay for the RdRP, N, and E genes in SARS-CoV-2 is verified.

RESULTS

The analytical system exhibits good analytical sensitivity (1000 copies/mL) and specificity (100%); however, the values of 86.7% and 100% for analytical accuracy deserved attention, compared with two other types of methods. Overall, the kit is potentially useful for SARS-CoV-2 diagnostic testing and meets the verification requirements.

CONCLUSION

Compliance with international standards, such as ISO 15189, is valuable for clinical laboratories and for improving laboratory medicine quality and safety. Normalization is essential for obtaining reliable results from the SARS-CoV-2 RNA RT-PCR assay. This study aims to develop an improved SARS-CoV-2 verification framework compared with traditional molecular diagnostic methods, given the urgency of implementing new assays in clinical laboratories.

Current diagnostic tools for coronaviruses-From laboratory diagnosis to POC diagnosis for COVID-19

The Coronavirus-2019 (COVID-19) pandemic has put tremendous strain on healthcare systems worldwide. It is challenging for clinicians to differentiate COVID-19 from other acute respiratory tract infections via clinical symptoms because those who are infected display a wide range of symptoms. An effective, point-of-care (POC) diagnostic tool could mitigate healthcare system strain, protect healthcare professionals, and support quarantine efforts. We believe that a POC tool can be developed that would be rapid, easy to use, and inexpensive. It could be used in the home, in resource-limited areas, and even in clinical settings. In this article, we summarize the current state of COVID-19 diagnostic methods and make a case for an all-in-one, highly sensitive POC assay that integrates antibody detection, protein detection, and serum cytokine detection to diagnose COVID-19 infection. We believe this article will provide insights into the current state of diagnostics for COVID-19, and promote additional research and tool development that could be exceptionally impactful.

Thoughts on What Chemists Can Contribute to Fighting SARS-CoV-2 - A Short Note on Hand Sanitizers, Drug Candidates and Outreach

The SARS-CoV-2 outbreak causing the respiratory disease COVID-19 has left many chemists in academia without an obvious option to contribute to fighting the pandemic. Some of our recent experiences indicate that there are ways to overcome this dilemma. A three-pronged approach is proposed.

Laboratory testing of SARS-CoV, MERS-CoV, and SARS-CoV-2 (2019-nCoV): Current status, challenges, and countermeasures

Emerging and reemerging infectious diseases are global public concerns. With the outbreak of unknown pneumonia in Wuhan, China in December 2019, a new coronavirus, SARS-CoV-2 has been attracting tremendous attention. Rapid and accurate laboratory testing of SARS-CoV-2 is essential for early discovery, early reporting, early quarantine, early treatment, and cutting off epidemic transmission. The genome structure, transmission, and pathogenesis of SARS-CoV-2 are basically similar to SARS-CoV and MERS-CoV, the other two beta-CoVs of medical importance. During the SARS-CoV and MERS-CoV epidemics, a variety of molecular and serological diagnostic assays were established and should be referred to for SARS-CoV-2. In this review, by summarizing the articles and guidelines about specimen collection, nucleic acid tests (NAT) and serological tests for SARS-CoV, MERS-CoV, and SARS-CoV-2, several suggestions are put forward to improve the laboratory testing of SARS-CoV-2. In summary, for NAT: collecting stool and blood samples at later periods of illness to improve the positive rate if lower respiratory tract specimens are unavailable; increasing template volume to raise the sensitivity of detection; putting samples in reagents containing guanidine salt to inactivate virus as well as protect RNA; setting proper positive, negative and inhibition controls to ensure high-quality results; simultaneously amplifying human RNase P gene to avoid false-negative results. For antibody test, diverse assays targeting different antigens, and collecting paired samples are needed.

Further Defining the Human Virome using NGS: Identification of Redondoviridae

In this issue of Cell Host & Microbe, Abbas et al. (2019) uncover a previously undefined family of single-stranded DNA viruses, Redondoviridae, in human ororespiratory sites. The presence of Redondoviridae associates with critical illness such as respiratory failure and periodontitis, illustrating the power of metagenomics to define the human virome.

Qualitative and Quantitative Determination of MERS-CoV S1-Specific Antibodies Using ELISA

Indirect enzyme-linked immunosorbent assay (ELISA) enables detection and quantification of antigen-specific antibodies in biological samples such as human or animal sera. Most current MERS-CoV serological assays such as neutralization, immunofluorescence, or protein microarray rely on handling of live MERS-CoV in high containment laboratories, highly trained personnel as well as the need for expensive and special equipment and reagents representing a hurdle for most laboratories especially when resources are limited. In this chapter, we describe a validated and optimized indirect ELISA protocol based on recombinant S1 subunit (amino acids 1-725) of MERS-CoV for qualitative and quantitative determination of MERS-CoV-binding antibodies.

International Biological Reference Preparations for Epidemic Infectious Diseases

Recent years have seen unprecedented investment in research and development for countermeasures for high-threat pathogens, including specific and ambitious objectives for development of diagnostics, therapeutics, and vaccines. The inadequate availability of biological reference materials for these pathogens poses a genuine obstacle in pursuit of these objectives, and the lack of a comprehensive and equitable framework for developing reference materials is a weakness. We outline the need for internationally standardized biological materials for high-threat pathogens as a core element of global health security. We also outline the key components of a framework for addressing this deficiency.

An updated roadmap for MERS-CoV research and product development: focus on diagnostics

Diagnostics play a central role in the early detection and control of outbreaks and can enable a more nuanced understanding of the disease kinetics and risk factors for the Middle East respiratory syndrome-coronavirus (MERS-CoV), one of the high-priority pathogens identified by the WHO. In this review we identified sources for molecular and serological diagnostic tests used in MERS-CoV detection, case management and outbreak investigations, as well as surveillance for humans and animals (camels), and summarised the performance of currently available tests, diagnostic needs, and associated challenges for diagnostic test development and implementation. A more detailed understanding of the kinetics of infection of MERS-CoV is needed in order to optimise the use of existing assays. Notably, MERS-CoV point-of-care tests are needed in order to optimise supportive care and to minimise transmission risk. However, for new test development, sourcing clinical material continues to be a major challenge to achieving assay validation. Harmonisation and standardisation of laboratory methods are essential for surveillance and for a rapid and effective international response to emerging diseases. Routine external quality assessment, along with well-characterised and up-to-date proficiency panels, would provide insight into MERS-CoV diagnostic performance worldwide. A defined set of Target Product Profiles for diagnostic technologies will be developed by WHO to address these gaps in MERS-CoV outbreak management.

Development and validation of different indirect ELISAs for MERS-CoV serological testing

Since 2012, MERS-CoV has caused up to 2220 cases and 790 deaths in 27 countries with Saudi Arabia being the most affected country with ~83.1% of the cases and ~38.8% local death rate. Current serological assays such as microneutralization (MN), plaque reduction neutralization, immunofluorescence, protein microarray or pseudoparticle neutralization assays rely on handling of live MERS-CoV in high containment laboratories or need for expensive and special equipment and reagents and highly trained personnel which represent a technical hurdle for most laboratories in resource-limited MERS-CoV endemic countries. Here, we developed, compared and evaluated three different indirect ELISAs based on MERS-CoV nucleocapsid protein (N), spike (S) ectodomain (amino acids 1–1297) and S1 subunit (amino acids 1–725) and compared them with MN assay. The developed ELISAs were evaluated using large number of confirmed seropositive (79 samples) and seronegative (274 samples) MERS-CoV human serum samples. Both rS1- and rS-ELISAs maintained high sensitivity and specificity (≥90%) across a wider range of OD values compared to rN-ELISA. Moreover, rS1- and rS-based ELISAs showed better agreement and correlation with MN assay in contrast to rN-ELISA. Collectively, our data demonstrate that rS1-ELISA and rS-ELISA are more reliable than rN-ELISA and represent a suitable choice for seroepidemiological testing and surveillance in MERS-CoV endemic regions.

MERS coronavirus outbreak: Implications for emerging viral infections

In September 2012, a novel coronavirus was isolated from a patient who died in Saudi Arabia after presenting with acute respiratory distress and acute kidney injury. Analysis revealed the disease to be due to a novel virus which was named Middle East Respiratory Coronavirus (MERS-CoV). There have been several MERS-CoV hospital outbreaks in KSA, continuing to the present day, and the disease has a mortality rate in excess of 35%. Since 2012, the World Health Organization has been informed of 2220 laboratory-confirmed cases resulting in at least 790 deaths. Cases have since arisen in 27 countries, including an outbreak in the Republic of Korea in 2015 in which 36 people died, but more than 80% of cases have occurred in Saudi Arabia.. Human-to-human transmission of MERS-CoV, particularly in healthcare settings, initially caused a ‘media panic’, however human-to-human transmission appears to require close contact and thus far the virus has not achieved epidemic potential. Zoonotic transmission is of significant importance and evidence is growing implicating the dromedary camel as the major animal host in spread of disease to humans. MERS-CoV is now included on the WHO list of priority blueprint diseases for which there which is an urgent need for accelerated research and development as they have the potential to cause a public health emergency while there is an absence of efficacious drugs and/or vaccines. In this review we highlight epidemiological, clinical, and infection control aspects of MERS-CoV as informed by the Saudi experience. Attention is given to recommended treatments and progress towards vaccine development.

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2220 laboratory-confirmed cases of MERS-CoV resulting in at least 790 deaths since 2012

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MERS-CoV is on the WHO list of priority blueprint diseases

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Zoonotic and human-to-human transmission modes need further clarification.

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No specific therapy has yet been approved.

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There is a need for well-controlled clinical trials on potential direct therapies.

The structure of the C-terminal domain of the nucleoprotein from the Bundibugyo strain of the Ebola virus in complex with a pan-specific synthetic Fab

The vast majority of platforms for the detection of viral or bacterial antigens rely on immunoassays, typically ELISA or sandwich ELISA, that are contingent on the availability of suitable monoclonal antibodies (mAbs). This is a major bottleneck, since the generation and production of mAbs is time-consuming and expensive. Synthetic antibody fragments (sFabs) generated by phage-display selection offer an alternative with many advantages over Fabs obtained from natural antibodies using hybridoma technology. Unlike mAbs, sFabs are generated using phage display, allowing selection for binding to specific strains or for pan-specificity, for identification of structural epitopes or unique protein conformations and even for complexes. Further, they can easily be produced in Escherichia coli in large quantities and engineered for purposes of detection technologies and other applications. Here, the use of phage-display selection to generate a pan-specific Fab (MJ20), based on a Herceptin Fab scaffold, with the ability to bind selectively and with high affinity to the C-terminal domains of the nucleoproteins (NPs) from all five known strains of the Ebola virus is reported. The high-resolution crystal structure of the complex of MJ20 with the antigen from the Bundibugyo strain of the Ebola virus reveals the basis for pan-specificity and illustrates how the phage-display technology can be used to manufacture suitable Fabs for use in diagnostic or therapeutic applications.

Inclusion of MERS-spike protein ELISA in algorithm to determine serologic evidence of MERS-CoV infection

The Centers for Disease Control and Prevention (CDC) algorithm for detecting presence of serum antibodies against Middle East Respiratory Syndrome coronavirus (MERS-CoV) in subjects with potential infections with the virus has included screening by indirect ELISA against recombinant nucleocapsid (N) protein and confirmation by immunofluorescent staining of infected monolayers and/or microneutralization titration. Other international groups include indirect ELISA assays using the spike (S) protein, as part of their serological determinations. In the current study, we describe development and validation of an indirect MERS-CoV S ELISA to be used as part of our serological determination for evidence of previous exposure to the virus.

An Opportunistic Pathogen Afforded Ample Opportunities: Middle East Respiratory Syndrome Coronavirus

The human coronaviruses (CoV) include HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1, some of which have been known for decades. The severe acute respiratory syndrome (SARS) CoV briefly emerged into the human population but was controlled. In 2012, another novel severely human pathogenic CoV—the Middle East Respiratory Syndrome (MERS)-CoV—was identified in the Kingdom of Saudi Arabia; 80% of over 2000 human cases have been recorded over five years. Targeted research remains key to developing control strategies for MERS-CoV, a cause of mild illness in its camel reservoir. A new therapeutic toolbox being developed in response to MERS is also teaching us more about how CoVs cause disease. Travel-related cases continue to challenge the world’s surveillance and response capabilities, and more data are needed to understand unexplained primary transmission. Signs of genetic change have been recorded, but it remains unclear whether there is any impact on clinical disease. How camels came to carry the virus remains academic to the control of MERS. To date, human-to-human transmission has been inefficient, but virus surveillance, characterisation, and reporting are key to responding to any future change. MERS-CoV is not currently a pandemic threat; it is spread mainly with the aid of human habit and error.

MERS, SARS and other coronaviruses as causes of pneumonia

Human coronaviruses (HCoVs) have been considered to be relatively harmless respiratory pathogens in the past. However, after the outbreak of the severe acute respiratory syndrome (SARS) and emergence of the Middle East respiratory syndrome (MERS), HCoVs have received worldwide attention as important pathogens in respiratory tract infection. This review focuses on the epidemiology, pathogenesis and clinical characteristics among SARS-coronaviruses (CoV), MERS-CoV and other HCoV infections.