At-home coronavirus testing: the next game-changer?

Diagnostics and analysis of SARS-CoV-2: current status, recent advances, challenges and perspectives

The disastrous spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has induced severe public healthcare issues and weakened the global economy significantly. Although SARS-CoV-2 infection is not as fatal as the initial outbreak, many infected victims suffer from long COVID. Therefore, rapid and large-scale testing is critical in managing patients and alleviating its transmission. Herein, we review the recent advances in techniques to detect SARS-CoV-2. The sensing principles are detailed together with their application domains and analytical performances. In addition, the advantages and limits of each method are discussed and analyzed. Besides molecular diagnostics and antigen and antibody tests, we also review neutralizing antibodies and emerging SARS-CoV-2 variants. Further, the characteristics of the mutational locations in the different variants with epidemiological features are summarized. Finally, the challenges and possible strategies are prospected to develop new assays to meet different diagnostic needs. Thus, this comprehensive and systematic review of SARS-CoV-2 detection technologies may provide insightful guidance and direction for developing tools for the diagnosis and analysis of SARS-CoV-2 to support public healthcare and effective long-term pandemic management and control.

Point-of-care nucleic acid tests: assays and devices

The COVID-19 pandemic (caused by the SARS_CoV_2 virus) has emphasized the need for quick, easy-to-operate, reliable, and affordable diagnostic tests and devices at the Point-of-Care (POC) for homes/fields/clinics. Such tests and devices will contribute significantly to the fight against the COVID-19 pandemic and any future infectious disease epidemic. Often, academic research studies and those from industry lack knowledge of each other's developments. Here, we introduced DNA Polymerase Chain Reaction (PCR) and isothermal amplification reactions and reviewed the current commercially available POC nucleic acid diagnostic devices. In addition, we reviewed the history and the recent advancements in an effort to develop reliable, quick, portable, cost-effective, and automatic point-of-care nucleic acid diagnostic devices, from sample to result. The purpose of this paper is to bridge the gap between academia and industry and to share important knowledge on this subject.

Human preparedness: Relational infrastructures and medical countermeasures in Sierra Leone

This paper examines health worker experiences in two areas of post-epidemic preparedness in Sierra Leone - vaccine trials and laboratory strengthening - to reflect on the place of people in current models of epidemic response. Drawing on ethnographic research and interviews with health workers in the aftermath of Ebola, it explores the hopes and expectations that interventions foster for frontline workers in under-resourced health systems, and describes the unseen work involved in sustaining robust response infrastructures. Our analysis focuses on what it means for the people who sustain health systems in an emergency to be 'prepared' for an epidemic. Human preparedness entails more than the presence of a labour force; it involves building and maintaining 'relational infrastructures', often fragile social and moral relationships between health workers, publics, governments, and international organisations. The COVID-19 pandemic has underscored the value of rethinking human resources from an anthropological perspective, and investing in the safety and support of people at the forefront of response. In describing the labour, personal losses, and social risks undertaken by frontline workers for protocols and practicality to meet in an emergency context, we describe the social process of preparedness; that is, the contextual engineering and investment that make response systems work.

A Biosensor Platform for Point-of-Care SARS-CoV-2 Screening

The COVID-19 pandemic remains a constant threat to human health, the economy, and social relations. Scientists around the world are constantly looking for new technological tools to deal with the pandemic. Such tools are the rapid virus detection tests, which are constantly evolving and optimizing. This paper presents a biosensor platform for the rapid detection of spike protein both in laboratory conditions and in swab samples from hospitalized patients. It is a continuation and improvement of our previous work and consists of a microcontroller-based readout circuit, which measures the capacitance change generated in an interdigitated electrode transducer by the presence either of sole spike protein or the presence of SARS-CoV-2 particles in swab samples. The circuit efficiency is calibrated by its correlation with the capacitance measurement of an LCR (inductance (L), capacitance (C), and resistance (R)) meter. The test result is made available in less than 2 min through the microcontroller’s LCD (liquid-crystal display) screen, whereas at the same time, the collected data are sent wirelessly to a mobile application interface. The novelty of this research lies in the potential it offers for continuous and effective screening of SARS-CoV-2 patients, which is facilitated and enhanced, providing big data statistics of COVID-19 in terms of space and time. This device can be used by individuals for SARS-CoV-2 testing at home, by health professionals for patient monitoring, and by public health agencies for monitoring the spatio-temporal spread of the virus.

Integrated Point-of-Care Molecular Diagnostic Devices for Infectious Diseases

The global outbreaks of deadly infectious diseases caused by pathogenic microorganisms have threatened public health worldwide and significantly motivated scientists to satisfy an urgent need for a rapid and accurate detection of pathogens. Traditionally, the culture-based technique is considered as the gold standard for pathogen detection, yet it has a long turnaround time due to the overnight culturing and pathogen isolation. Alternatively, nucleic acid amplification tests provide a relatively shorter turnaround time to identify whether pathogens exist in individuals with high sensitivity and high specificity. In most cases, nucleic acid amplification tests undergo three steps: sample preparation, nucleic acid amplification, and signal transduction. Despite the explosive advancement in nucleic acid amplification and signal transduction technologies, the complex and labor-intensive sample preparation steps remain a bottleneck to create a transformative integrated point-of-care (POC) molecular diagnostic device. Researchers have attempted to simplify and integrate the sample preparations for nucleic acid-based molecular diagnostic devices with innovative progress in integration strategies, engineered materials, reagent storages, and fluid actuation. Therefore, understanding the know-how and obtaining truthful knowledge of existing integrated POC molecular diagnostic devices comprising sample preparations, nucleic acid amplification, and signal transduction can generate innovative solutions to achieve personalized precision medicine and improve global health.In this Account, we discuss the challenges of automated sample preparation solutions integrated with nucleic acid amplification and signal transduction for rapid and precise home diagnostics. Blood, nasal swab, saliva, urine, and stool are emphasized as the most commonly used clinical samples for integrated POC molecular diagnostics of infectious diseases. Even though these five types of samples possess relatively correlated biomarkers due to the human body's circulatory system, each shows unique properties and exclusive advantages for molecular diagnostics in specific situations, which are included in this Account. We examine different integrated POC devices for sample preparation, which includes pathogen isolation and enrichment from the crude sample and nucleic acid purification from isolated pathogens. We present the promising on-chip integration approaches for nucleic acid amplification. We also investigate the on-chip integration methods for reagent storage, which is crucial to simplify the manual operation for end-users. Finally, we present several integrated POC molecular diagnostic devices for infectious diseases. The integrated sample preparation and nucleic acid amplification approach reviewed here can potentially impact the next generation of POC molecular home diagnostic chips, which will significantly impact public health, emergency medicine, and global biosecurity.

Clinical and Economic Effects of Widespread Rapid Testing to Decrease SARS-CoV-2 Transmission

BACKGROUND

The value of frequent, rapid testing to reduce community transmission of SARS-CoV-2 is poorly understood.

OBJECTIVE

To define performance standards and predict the clinical, epidemiologic, and economic outcomes of nationwide, home-based antigen testing.

DESIGN

A simple compartmental epidemic model that estimated viral transmission, portrayed disease progression, and forecast resource use, with and without testing.

DATA SOURCES

Parameter values and ranges as informed by Centers for Disease Control and Prevention guidance and published literature.

TARGET POPULATION

U.S. population.

TIME HORIZON

60 days.

PERSPECTIVE

Societal; costs included testing, inpatient care, and lost workdays.

INTERVENTION

Home-based SARS-CoV-2 antigen testing.

OUTCOME MEASURES

Cumulative infections and deaths, number of persons isolated and hospitalized, and total costs.

RESULTS OF BASE-CASE ANALYSIS

Without a testing intervention, the model anticipates 11.6 million infections, 119 000 deaths, and $10.1 billion in costs ($6.5 billion in inpatient care and $3.5 billion in lost productivity) over a 60-day horizon. Weekly availability of testing would avert 2.8 million infections and 15 700 deaths, increasing costs by $22.3 billion. Lower inpatient outlays ($5.9 billion) would partially offset additional testing expenditures ($12.5 billion) and workdays lost ($14.0 billion), yielding incremental cost-effectiveness ratios of $7890 per infection averted and $1 430 000 per death averted.

RESULTS OF SENSITIVITY ANALYSIS

Outcome estimates vary widely under different behavioral assumptions and testing frequencies. However, key findings persist across all scenarios, with large reductions in infections, mortality, and hospitalizations. Costs per death averted are roughly an order of magnitude lower than commonly accepted willingness-to-pay values per statistical life saved ($5 to $17 million).

LIMITATIONS

Analysis was restricted to at-home testing. There are uncertainties concerning test performance.

CONCLUSION

High-frequency home testing for SARS-CoV-2 with an inexpensive, imperfect test could contribute to pandemic control at justifiable cost and warrants consideration as part of a national containment strategy.

PRIMARY FUNDING SOURCE

National Institutes of Health.

COVID-19 Diagnostic Strategies. Part I: Nucleic Acid-Based Technologies

The novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused respiratory infection, resulting in more than two million deaths globally and hospitalizing thousands of people by March 2021. A considerable percentage of the SARS-CoV-2 positive patients are asymptomatic or pre-symptomatic carriers, facilitating the viral spread in the community by their social activities. Hence, it is critical to have access to commercialized diagnostic tests to detect the infection in the earliest stages, monitor the disease, and follow up the patients. Various technologies have been proposed to develop more promising assays and move toward the mass production of fast, reliable, cost-effective, and portable PoC diagnostic tests for COVID-19 detection. Not only COVID-19 but also many other pathogens will be able to spread and attach to human bodies in the future. These technologies enable the fast identification of high-risk individuals during future hazards to support the public in such outbreaks. This paper provides a comprehensive review of current technologies, the progress in the development of molecular diagnostic tests, and the potential strategies to facilitate innovative developments in unprecedented pandemics.

Clinical and Economic Impact of Widespread Rapid Testing to Decrease SARS-CoV-2 Transmission.. [PMID: 33564779 PMCID: PMC7872371 DOI: 10.1101/2021.02.06.21251270]

Background:

The value of frequent, rapid testing to reduce community transmission of SARS-CoV-2 is poorly understood.

Objective:

To define performance standards and predict the clinical, epidemiological, and economic outcomes of nationwide, home-based, antigen testing.

Design:

A simple compartmental epidemic model estimated viral transmission, clinical history, and resource use, with and without testing.

Data Sources:

Parameter values and ranges informed by Centers for Disease Control guidance and published literature.

Target Population:

United States population.

Time Horizon:

60 days.

Perspective:

Societal. Costs include: testing, inpatient care, and lost workdays.

Intervention:

Home-based SARS-CoV-2 antigen testing.

Outcome Measures:

Cumulative infections and deaths, numbers isolated and/or hospitalized, and total costs.

Results of Base-Case Analysis:

Without a testing intervention, the model anticipates 15 million infections, 125,000 deaths, and $10.4 billion in costs ($6.5 billion inpatient; $3.9 billion lost productivity) over a 60-day horizon. Weekly availability of testing may avert 4 million infections and 19,000 deaths, raising costs by $21.5 billion. Lower inpatient outlays ($5.9 billion) would partially offset additional testing expenditures ($12.0 billion) and workdays lost ($13.9 billion), yielding incremental costs per infection (death) averted of $5,400 ($1,100,000).

Results of Sensitivity Analysis:

Outcome estimates vary widely under different behavioral assumptions and testing frequencies. However, key findings persist across all scenarios: large reductions in infections, mortality, and hospitalizations; and costs per death averted roughly an order of magnitude lower than commonly accepted willingness-to-pay values per statistical life saved ($5-17 million).

Limitations:

Analysis restricted to at-home testing and limited by uncertainties about test performance.

Conclusion:

High-frequency home testing for SARS-CoV-2 using an inexpensive, imperfect test could contribute to pandemic control at justifiable cost and warrants consideration as part of a national containment strategy.