New and developing diagnostic platforms for COVID-19: A systematic review

Clinical performance of the Roche Cobas Liat SARS-CoV-2 & influenza A/B assay: A systematic review and meta-analysis

Respiratory tract infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses are persistent and critical. The Cobas Liat SARS-CoV-2 & influenza A/B assay (Multiplex Liat), the FDA-authorized point-of-care reverse transcriptase polymerase chain reaction (RT-PCR) assay, has a turnaround time of 20 min and high accuracy. This study evaluates the pooled performance of this assay to provide practical information. This meta-analysis was registered in PROSPERO (registration number: CRD42023467579). A systematic literature search was conducted within PubMed, Ovid-EMBASE, and the Cochrane Library for articles evaluating the accuracy of the Multiplex Liat assay through September 2023. A random-effects model was used to calculate the pooled diagnostic values with real-time RT-PCR (rRT-PCR) as a reference test. A total of 4,705 samples from eight studies were included in the primary meta-analysis. The overall pooled sensitivity and specificity of Multiplex Liat were 100.0 % (95 % confidence interval [CI] = 96.7 %-100.0 %) and 99.7 % (95 % CI = 98.7 %-99.9 %), respectively. The presence of variants of concern or in-house rRT-PCR assays as reference standards did not significantly affect the pooled diagnostic performance of the Multiplex Liat. When 5,333 samples from nine studies were assessed for sensitivity, the pooled sensitivity was 100.0 % (95 % CI = 85.8 %-100.0 %) without a significant difference. This meta-analysis demonstrates the usefulness of Multiplex Liat for the detection of SARS-CoV-2 based on pooled diagnostic values. These practical findings may facilitate appropriate settings for the diagnosis and management of patients with respiratory tract infections.

Graphene Field Effect Biosensor for Concurrent and Specific Detection of SARS-CoV-2 and Influenza

The SARS-CoV-2 pandemic has highlighted the need for devices capable of carrying out rapid differential detection of viruses that may manifest similar physiological symptoms yet demand tailored treatment plans. Seasonal influenza may be exacerbated by COVID-19 infections, increasing the burden on healthcare systems. In this work, we demonstrate a technology based on liquid-gated graphene field-effect transistors (GFETs), for rapid and ultraprecise sensing and differentiation of influenza and SARS-CoV-2 surface protein. Most distinctively, the device consists of 4 onboard GFETs arranged in a quadruple architecture, where each quarter is functionalized individually (with either antibodies or chemically passivated control) but measured jointly. The sensor platform was tested against a range of concentrations of viral surface proteins from both viruses with the lowest tested and detected concentration at ∼50 ag/mL, or 88 zM for COVID-19 and 227 zM for Flu, which is 5-fold lower than the values reported previously on a similar platform. Unlike the classic real-time polymerase chain reaction test, which has a turnaround time of a few hours, the graphene technology presents an ultrafast response time of ∼10 s even in complex and clinically relevant media such as saliva. Thus, we have developed a multianalyte, highly sensitive, and fault-tolerant technology for rapid diagnostic of contemporary, emerging, and future pandemics.

Application of Deep Learning Techniques in Diagnosis of Covid-19 (Coronavirus): A Systematic Review

Covid-19 is now one of the most incredibly intense and severe illnesses of the twentieth century. Covid-19 has already endangered the lives of millions of people worldwide due to its acute pulmonary effects. Image-based diagnostic techniques like X-ray, CT, and ultrasound are commonly employed to get a quick and reliable clinical condition. Covid-19 identification out of such clinical scans is exceedingly time-consuming, labor-intensive, and susceptible to silly intervention. As a result, radiography imaging approaches using Deep Learning (DL) are consistently employed to achieve great results. Various artificial intelligence-based systems have been developed for the early prediction of coronavirus using radiography pictures. Specific DL methods such as CNN and RNN noticeably extract extremely critical characteristics, primarily in diagnostic imaging. Recent coronavirus studies have used these techniques to utilize radiography image scans significantly. The disease, as well as the present pandemic, was studied using public and private data. A total of 64 pre-trained and custom DL models concerning imaging modality as taxonomies are selected from the studied articles. The constraints relevant to DL-based techniques are the sample selection, network architecture, training with minimal annotated database, and security issues. This includes evaluating causal agents, pathophysiology, immunological reactions, and epidemiological illness. DL-based Covid-19 detection systems are the key focus of this review article. Covid-19 work is intended to be accelerated as a result of this study.

Development and Evaluation of Enzyme-Linked Viral Immune Capture Assay for Detection of SARS-CoV-2

The pandemic of COVID-19 was caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 and it has prompted unprecedented research activities for vaccines, therapeutics, and diagnostics. The real-time reverse transcriptase-polymerase chain reaction (RT-PCR) is the gold standard method of diagnosis; however, immune-based assays offer cost-effective, deployable, easy-to-read solutions for diagnosis and surveillance. Here, we present the development, optimization, and testing of an enzyme-linked viral immune capture assay (ELVICA). It utilizes the spike antigen as the detected target of the virus and antibody-coated beads to capture the virus and enrich the detection. This method can be readout by luminescent and colorimetric equipment. It can also be visualized by the imaging system, offering a variety of detection approaches. ELVICA showed specificity to SARS-CoV-2-pseudotyped viruses as compared to MERS-CoV-pseudotyped viruses. As compared to RT-PCR, ELVICA showed high compatibility in detecting the virus in patient respiratory samples, especially for samples that are below a Ct value of 32 in RT-PCR. This assay is readily adaptable for detecting other pathogens and serves as a quick and affordable diagnostic tool.

A Regional Pooling Intervention in a High-Throughput COVID-19 Diagnostic Laboratory to Enhance Throughput, Save Resources and Time Over a Period of 6 Months

An effective and rapid diagnosis has great importance in tackling the ongoing COVID-19 pandemic through isolation of the infected individuals to curb the transmission and initiation of specialized treatment for the disease. It has been proven that enhanced testing capacities contribute to efficiently curbing SARS-CoV-2 transmission during the initial phases of the outbreaks. RT-qPCR is considered a gold standard for the diagnosis of COVID-19. However, in resource-limited countries expenses for molecular diagnosis limits the diagnostic capacities. Here, we present interventions of two pooling strategies as 5 sample pooling (P-5) and 10 sample pooling (P-10) in a high-throughput COVID-19 diagnostic laboratory to enhance throughput and save resources and time over a period of 6 months. The diagnostic capacity was scaled-up 2.15-folds in P-5 and 1.8-fold in P-10, reagents (toward RNA extraction and RT-qPCR) were preserved at 75.24% in P-5 and 86.21% in P-10, and time saved was 6,290.93 h in P-5 and 3147.3 h in P-10.

Colorimetric and Electrochemical Methods for the Detection of SARS-CoV-2 Main Protease by Peptide-Triggered Assembly of Gold Nanoparticles

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro) has been regarded as one of the ideal targets for the development of antiviral drugs. The currently used methods for the probing of Mpro activity and the screening of its inhibitors require the use of a double-labeled peptide substrate. In this work, we suggested that the label-free peptide substrate could induce the aggregation of AuNPs through the electrostatic interactions, and the cleavage of the peptide by the Mpro inhibited the aggregation of AuNPs. This fact allowed for the visual analysis of Mpro activity by observing the color change of the AuNPs suspension. Furthermore, the co-assembly of AuNPs and peptide was achieved on the peptide-covered electrode surface. Cleavage of the peptide substrate by the Mpro limited the formation of AuNPs/peptide assembles, thus allowing for the development of a simple and sensitive electrochemical method for Mpro detection in serum samples. The change of the electrochemical signal was easily monitored by electrochemical impedance spectroscopy (EIS). The detection limits of the colorimetric and electrochemical methods are 10 and 0.1 pM, respectively. This work should be valuable for the development of effective antiviral drugs and the design of novel optical and electrical biosensors.

Application experience of a rapid nucleic acid detection system for COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is raging worldwide. The COVID-19 outbreak caused severe threats to the life and health of all humans caused by SARS-CoV-2. Clinically, there is an urgent need for an in vitro diagnostic product to detect SARS-CoV-2 nucleic acid quickly. Under this background, commercial SARS-CoV-2 nucleic acid POCT products came into being. However, how to choose these products and how to use these products in a standardized way have brought new puzzles to clinical laboratories. This paper focuses on evaluating the performance of these commercial SARS-CoV-2 nucleic acid POCT products and helps the laboratory make the correct choice. At the same time, to standardize the use of this kind of product, this paper also puts forward corresponding suggestions from six elements of total quality management, namely, human, machine, material, method, environment, and measurement. In addition, this paper also puts forward some ideas on the future development direction of POCT products.

Aptamer-based biosensors and their implications in COVID-19 diagnosis

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a novel infectious member of the coronavirus family, has caused millions of cases of infection and deaths all over the world, and been declared a pandemic by the World Health Organization. Conventional laboratory-based diagnostic testing has faced extreme difficulties in meeting the overwhelming demand for testing worldwide, and this has brought about a pressing need for cost-effective rapid diagnosis. There has been a surge in the number of prototypes of diagnostic kits developed, although many of these have been found to be lacking in terms of their accuracy and sensitivity. One type of chip-based diagnostic platform is the aptamer-based biosensor. Aptamers are artificially synthesized oligonucleotides that are capable of specifically binding to a target antigen. As of now, some aptamers have been reported for SARS-CoV-2. Although many ultrasensitive aptasensors have been developed for viruses, few have been successfully adapted for SARS-CoV-2 detection. Our review discusses the recent developments in the domain of SARS-CoV-2 specific aptamer isolation, the design of electrochemical and optical aptasensors, and the implications of aptasensor-based COVID-19 diagnosis.

Optimizing testing regimes for the detection of COVID-19 in children and older adults

Introduction: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is a major pandemic and continuously emerging due to unclear prognosis and unavailability of reliable detection tools. Older adults are more susceptible to COVID-19 than children showing mature Angiotensin-Converting Enzyme 2 (ACE2), low concentration of immune targets, and comorbid conditions. Several detection platforms have been commercialized to date and more are in pipeline, however, the rate of false-positive results and rapid mutation of SARS-CoV-2 is increasing. Additionally, physiological, and geographical variations of affected individuals are also calling for diagnostic methods optimization.Areas Covered: Extensive information related to the optimization and usefulness of SARS-CoV-2 diagnostic methods based on sensitivity and specificity as definitive and feasible investigative tools is discussed. Moreover, an option of combining laboratory diagnostic methods to improve diagnostic strategies is also proposed and discussed in the comparative section of optimization studies.Expert Opinion: The review article explains the importance of optimization strategies for SARS-CoV-2 detection in children and older adults. There are advancements in COVID-19 detection including CRISPR-based, electrochemical, and optical-based sensing systems. However, the lack of sufficient studies on a comparative evaluation of standardized SARS-CoV-2 diagnostic methods among children and older adults, limit the authentication of commercialized kits.

A systematic review on SARS-CoV-2-associated fungal coinfections

A severe pandemic of Coronavirus Disease (COVID‐19) has been sweeping the globe since 2019, and this time, it did not stop, with frequent mutations transforming into virulent strains, for instance, B.1.1.7, B.1.351, and B.1.427. In recent months, a fungal infection, mucormycosis has emerged with more fatal responses and significantly increased mortality rate. To measure the severity and potential alternative approaches against black fungus coinfection in COVID‐19 patients, PubMed, Google Scholar, World Health Organization (WHO) newsletters, and other online resources, based on the cases reported and retrospective observational analysis were searched from the years 2015–2021. The studies reporting mucormycosis with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) coinfection and/or demonstrating potential risk factors, such as a history of diabetes mellitus or suppressed immune system were included, and reports published in non‐English language were excluded. More than 20 case reports and observational studies on black fungus coinfection in COVID‐19 patients were eligible for inclusion. The results indicated that diabetes mellitus, hyperglycemic, and immunocompromised COVID‐19 patients with mucormycosis were at a higher risk. We found that it was prudent to assess the potential risk factors and severity of invasive mycosis via standardized diagnostic and clinical settings. Large‐scale studies need to be conducted to identify early biomarkers and optimization of diagnostic methods has to be established per population and geographical variation. This will not only help clinicians around the world to detect the coinfection in time but also will prepare them for future outbreaks of other potential pandemics.

Observational studies and case reports of Post‐COVID black fungus co‐infection highlighted in review.

Along with risk factors, radiological interventions of black fungus co‐infection in COVID‐19 patients and challenges for accurate diagnosis were elaborated.

The review discusses interconnection between fungus and SARS‐CoV‐2 co‐infection of mechanism to identify potential biomarkers.

Our conclusion will contribute to motivate researchers to design follow‐up plans for black fungus infection in COVID‐19.

Detection of SARS-CoV-2 at the point of care

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent of COVID-19. Testing for SARS-CoV-2 infection is a critical element of the public health response to COVID-19. Point-of-care (POC) tests can drive patient management decisions for infectious diseases, including COVID-19. POC tests are available for the diagnosis of SARS-CoV-2 infections and include those that detect SARS-CoV-2 antigens as well as amplified RNA sequences. We provide a review of SARS-CoV-2 POC tests including their performance, settings for which they might be used, their impact and future directions. Further optimization and validation, new technologies as well as studies to determine clinical and epidemiological impact of SARS-CoV-2 POC tests are needed.

Does the COVID-19 seroconversion in older adults resemble the young?

High antibody titers have been found to correlate with the severity of coronavirus disease 2019 (COVID‐19) disease. Therefore, antibody titers may be higher in older adults, whose disease is known to have a more severe course than younger ones. This study aimed to compare the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) immunoglobulin G (IgG) antibody level in the reverse transcription‐polymerase chain reaction (RT‐PCR) to test positive older adults with young. Patients aged ≥18 with positive RT‐PCR and checked serum IgG antibodies between November 1, 2020 and January 13, 2021 were included. The IgG antibody levels and the time between RT‐PCR positivity with the antibody levels were recorded. A total of 1071 patients were divided into two groups as Group 1 <60 years old (n = 902) and Group 2 ≥60 years old (n = 169). The SARS‐CoV‐2 IgG antibody titers were higher in Group 2 (p = 0.001). This height was present in the first 3 months after positive RT‐PCR. While the antibody titers were compared by dividing Group 2 into the three groups according to age ranges (60–69, 70–79, and ≥80 years), the antibody titer was higher in ≥80 years patients (p = 0.044). High COVID‐19 IgG antibody levels may be associated with the severity of the disease. Also, the humoral immunity advantage was seen in the first 3 months in the older patients, which suggests that older adults with COVID‐19 may develop reinfection in the long term.