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1.
Scientific African ; : e01328, 2022.
Article in English | ScienceDirect | ID: covidwho-1983927

ABSTRACT

Many households in sub-Saharan Africa (SSA) depend on wood-fuel and biomass for cooking, with associated health and negative environmental impacts. Indoor air pollution from these traditional cooking technologies and practices lead to a number of deaths each year. Clean and smokeless cooking technologies are necessary to minimize respiratory related infections associated with traditional cooking technologies. In addition, modern energy cooking services (MECS), which have lower levelized lifecycle cost have a part to play for post COVID recovery and growth in the sub-region. In this study, a novel pressurized solar electric cooker (PSEC) using diodes as the heating element has been constructed and tested in Kumasi city, Ghana. The PSEC comprises 150 Wp solar panel, 3.3 litre cooking volume, and with the system integrated with PCM for thermal energy storage. From the experiments conducted in this study, the diode-heating element was able to charge the PCM (erythritol) and maintain it at an average temperature of 118 °C to cook rice, which is a common staple food enjoyed in many households in SSA. The result revealed that when the PCM integrated as energy storage medium was fully charged, the PSEC had fast cooking time of 50 minutes. Financial analysis also revealed that the PSEC has potential cost savings of US$ 575 and US$ 365, compared to cooking with charcoal and grid electricity, respectively, over a 10-year period.

2.
Applied and Computational Harmonic Analysis ; 2022.
Article in English | ScienceDirect | ID: covidwho-1926136

ABSTRACT

Three families of super-resolution (SR) wavelets Ψv,ng(x), Ψu,n,ms(x) and Ψw,n,mds(x), to be called Gaussian SR (GSR), spline SR (SSR) and dual-spline SR (DSSR) wavelets, respectively, are introduced in this paper for resolving the super-resolution problem of recovering any point-mass h(y)=∑ℓ=1Lcℓδ(y−σℓ), with ;σℓ−σk;≥η for ℓ≠k, σℓ≠0, and ;cℓ;>η⁎ for all ℓ,k=1,…,L, where η>0 and η⁎>0 are allowed to be arbitrarily small. Let Ψα,n=Ψv,ng, Ψu,n,ms or Ψw,n,mds, with α=v,u or w, respectively, where m=12,1,2,⋯ is suppressed. The SR wavelets are designed to have the n-th order of vanishing moments, with Fourier transform of their complex conjugates Ψ¯ˆα,n(x) to possess the following properties: (i) Ψ¯ˆα,n(x)≥0 for all x∈R, (ii) maxx⁡Ψ¯ˆα,n(x)=Ψ¯ˆα,n(κ)=ξn, where κ≐2.331122371 and ξ≐1.449222080 are positive constants independent of n,α and m, and (iii) the widths (or standard deviations) of Ψ¯ˆα,n(x), with center at κ, tends to 0 very fast for large values of α. While the most popular approach to resolve this super-resolution problem is to consider the Fourier transform d(x)=∑ℓ=1Lcℓe−iσℓx of h(y) as the “data function” for solving the inverse problem of recovering L, σ1,⋯,σL and c1,⋯,cL of the point-mass d(x), our proposed approach is to consider the “enhanced data function” D(a;α,n):=FΨα,n(a)=∑ℓ=1LcℓΨ¯ˆα,n(aσℓ), where FΨα,n(a), to be called the search function in this paper, is obtained by taking the continuous wavelet transform (CWT): (WΨα,nd)(t,a)=∫−∞∞Ψα,n(y−ta)‾d(y)dya of the data function d(x), with Ψα,n as the analysis wavelet, followed by applying wavelet thresholding to “de-noise” the data function d(x), by choosing an appropriate thresholding parameter γ>0, with γ<η⁎×ξn, in order not to remove any of the coefficients cℓ, where ℓ=1,⋯,L;and finally by setting t=0. Hence, the enhanced data function D(a;α,n) is at least cleaner than the data function d(x). In our proposed approach, instead of directly recovering σ1,⋯,σL as in the published literature, we propose a “divide and conquer” strategy: first by applying “bottom-up thresholding” of the search function FΨα,n(a), with thresholding parameter γ⁎>0 close to but not exceeding η⁎×ξn, to separate the set of the local extrema locations aℓ:=κσℓ of the function FΨα,n(a) in {a∈R:a≠0} into disjoint intervals of clusters, with more and smaller intervals and less number of local extrema aℓ in each interval for larger values of α;and secondly, by applying “top-down thresholding” to extract, one-by-one, of all local maxima, followed by all local minima (after a sign change), for each and every cluster. A desired leeway Δ>0 and lower bounds of the choice of the width parameter α are derived for the iterative application of top-down thresholding. Extension to Rs for s≥2 is also studied in this paper. For s=2, we observe that the imagery of the enhanced data function for a single point-mass at (σ1,σ2) where σ1,σ2≠0, resembles that of an “Airy disk” with center at (κ/σ1,κ/σ2) in light microscopy and celestial telescopy of point-masses.

3.
Front Public Health ; 10: 836328, 2022.
Article in English | MEDLINE | ID: covidwho-1809615

ABSTRACT

Real-world data are needed to establish SARS-CoV-2 rapid antigen testing (RAT) as an effective and reliable approach for SARS-CoV-2 screening. This study included 1,952,931 individuals who provided upper respiratory specimens during SARS-CoV-2 screening at CityMD urgent care locations in the New York metropolitan area from October 2020 to March 2021. Positive and negative results, as determined by the BD Veritor™ System for Rapid Detection of SARS-CoV-2 antigen (Veritor), were obtained for all individuals, with reflex reverse transcriptase-polymerase chain reaction (RT-PCR) testing performed on a case-by-case basis, per standard of care. Using verification bias adjustment, two alternative model assumptions were utilized for RAT results with missing reflex RT-PCR results. The worst antigen diagnostic performance estimates asserted that missing RT-PCR results would show a distribution similar to those RT-PCR results actually obtained, based on symptom category. The best antigen diagnostic performance estimates asserted that individuals without RT-PCR results had a clinical presentation consistent with RAT results, and, therefore, missing RT-PCR results would agree with RAT results. For patients with symptoms or high-risk exposure, 25.3% (n = 86,811/343,253) of RAT results were positive; vs. 3.4% (n = 53,046/1,559,733) positive for asymptomatic individuals without high-risk exposure. Reflex RT-PCR results were obtained from 46.3% (n = 158,836/343,253) and 13.8% (n = 215,708/1,559,733) of symptomatic and asymptomatic individuals, respectively. RT-PCR confirmed 94.4% (4,265/4,518) of positive and 90.6% (139,759/154,318) of negative RAT results in symptomatic individuals; and confirmed 83.4% (6,693/8,024) of positive and 95.3% (197,955/207,684) of negative RAT results in asymptomatic individuals. Applied assumptions for missing reflex RT-PCR results led to worst performance sensitivity estimates of 77.2 and 38.5% in the symptomatic and asymptomatic populations, respectively; assumptions for best performance estimates led to sensitivity values of 85.6 and 84.2%, respectively. Specificity values, regardless of assumptions or symptom category, ranged from 97.9-99.9%. At 10% SARS-CoV-2 prevalence, RAT positive predictive value was 86.9 and 99.0% for worst and best performance estimates across the total population, respectively; negative predictive values were >95% regardless of the applied assumption. Veritor test performance was consistent with that listed in the manufacturer instructions for use for symptomatic individuals. Real-world evidence should be gathered on RATs to support their efficacy as SARS-CoV-2 persists.


Subject(s)
COVID-19 Serological Testing , COVID-19 , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing , Humans , SARS-CoV-2 , Sensitivity and Specificity
4.
Microbiol Spectr ; 10(2): e0180721, 2022 04 27.
Article in English | MEDLINE | ID: covidwho-1784772

ABSTRACT

Differential diagnosis of COVID-19 and/or influenza (flu) at point of care is critical for efficient patient management and treatment of both these diseases. The study presented here characterizes the BD Veritor System for Rapid Detection of SARS-CoV-2 and Flu A+B ("Veritor SARS-CoV-2/Flu") triplex assay. The performance for SARS-CoV-2 detection was determined using 298 specimens from patients reporting COVID-19 symptoms within 7 days from symptom onset (DSO) in comparison with the Lyra SARS-CoV-2 RT-PCR (reverse transcriptase PCR) assay ("Lyra SARS-CoV-2") as the reference. The performance for flu A and flu B detection was determined using 75 influenza-positive and 40 influenza-negative retrospective specimens in comparison with the previously FDA-cleared BD Veritor System for Rapid Detection of Flu A+B assay ("Veritor Flu") as the reference. The Veritor SARS-CoV-2/Flu assay met the FDA EUA acceptance criteria (86.7%; 95% confidence interval [95% CI]: 75.8 to 93.1) for SARS-CoV-2 testing compared to Lyra SARS-CoV-2. The Veritor SARS-CoV-2/Flu assay also demonstrated 100% agreement with the Veritor Flu for Flu A+B assay. For flu A detection, the lower bound of the 95% CI was 91.2%; for flu B detection, the lower bound was 90.0%. The dual detection capability of Veritor SARS-CoV-2/Flu for the etiologic agents causing COVID-19 and flu will allow efficient differentiation between the two illnesses, inform disease management, and facilitate optimal treatment. IMPORTANCE COVID-19 and flu are two respiratory illnesses which share similar clinical symptoms. The BD Veritor SARS-CoV-2/Flu assay has high sensitivity and specificity for detecting the SARS-CoV-2 and influenza A/B, the two etiologic agents causing COVID-19 and flu, respectively. This dual detection capability is critical when overlap occurs between the COVID-19 pandemic and the flu season. This triplex assay will allow efficient differentiation between the two respiratory illnesses and support a point-of-care physician diagnosis to facilitate the proper treatment and disease management for patients exhibiting overlapping symptoms.


Subject(s)
COVID-19 , Influenza, Human , COVID-19/diagnosis , COVID-19 Testing , Humans , Influenza, Human/diagnosis , Pandemics , Point-of-Care Systems , Retrospective Studies , SARS-CoV-2 , Sensitivity and Specificity
5.
Journal of Corporation Law ; 47(2):277-331, 2022.
Article in English | ProQuest Central | ID: covidwho-1762308

ABSTRACT

This Article is the first to analyze a sea change in bank governance-the precipitous rise of lawyer-directors in the past two decades. Using novel empirical evidence, we show that lawyer-directors are associated with efficient changes in risk management and significant increases in bank value. Banks with lawyer-directors assume more risk in ordinary circumstances and less risk when a crisis arises, in each case making those banks more valuable. Understanding that change in governance is vital in light of the COVID-19 crisis, which has transformed the risks that banks face. IVe show that-beyond new regulation, as others have proposed-having a director who thinks like a lawyer is likely to make boards more effective in managing new risks. Lawyer-directors add value to boards by drawing on advocacy skills to analyze opposing points of view, an essential quality in managing risk. They are more likely to make complex information more accessible to a board and to build a consensus among different points of view. Lawyer-directors, of course, are also skilled at assessing litigation and regulatory risks, which have grown significantly in recent years. Our findings challenge the standard framing of the board. Improving board efficacy requires a more nuanced understanding than has happened to date of the effect on boards of board composition and directors skills. We use the example of bank lawyer-directors to begin addressing that shortcoming. Beyond banks, however, our findings underscore the need for a new approach to analyzing what really matters for boards and corporate governance.

6.
Water International ; 45(5):416-422, 2021.
Article in English | GIM | ID: covidwho-1532260

ABSTRACT

Household water insecurity may exacerbate the COVID-19 pandemic and exact an even greater toll on people, especially in Africa, Asia and Latin America, simply because too many people do not have access to safe and secure water services, including water supply and sanitation, at home. Recent studies have shown that as many as a quarter of households in the Global South may be unable to practise necessary hand hygiene. Megacities may be at particular risk of being unable to manage the COVID-19 pandemic due to sheer population density as well as a lack of reliable clean water and sanitation. Problems of water insecurity are not restricted to the Global South but extend into higher-income countries as well. The steady decline in provision of public sanitation around the world, even in wealthy countries, makes adequate hygiene an even more intractable problem.

7.
Front Microbiol ; 12: 714242, 2021.
Article in English | MEDLINE | ID: covidwho-1485072

ABSTRACT

Tests that detect the presence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antigen in clinical specimens from the upper respiratory tract can provide a rapid means of coronavirus disease 2019 (COVID-19) diagnosis and help identify individuals who may be infectious and should isolate to prevent SARS-CoV-2 transmission. This systematic review assesses the diagnostic accuracy of SARS-CoV-2 antigen detection in COVID-19 symptomatic and asymptomatic individuals compared to quantitative reverse transcription polymerase chain reaction (RT-qPCR) and summarizes antigen test sensitivity using meta-regression. In total, 83 studies were included that compared SARS-CoV-2 rapid antigen-based lateral flow testing (RALFT) to RT-qPCR for SARS-CoV-2. Generally, the quality of the evaluated studies was inconsistent; nevertheless, the overall sensitivity for RALFT was determined to be 75.0% (95% confidence interval: 71.0-78.0). Additionally, RALFT sensitivity was found to be higher for symptomatic vs. asymptomatic individuals and was higher for a symptomatic population within 7 days from symptom onset compared to a population with extended days of symptoms. Viral load was found to be the most important factor for determining SARS-CoV-2 antigen test sensitivity. Other design factors, such as specimen storage and anatomical collection type, also affect the performance of RALFT. RALFT and RT-qPCR testing both achieve high sensitivity when compared to SARS-CoV-2 viral culture.

8.
J Clin Microbiol ; 59(12): e0101921, 2021 11 18.
Article in English | MEDLINE | ID: covidwho-1443351

ABSTRACT

Nucleic acid amplification testing (NAAT) for SARS-CoV-2 is the standard approach for confirming COVID-19 cases. This study compared results between two emergency use authorization (EUA) NAATs, with two additional EUA NAATs utilized for discrepant testing. The limits of detection (LOD) for the BD SARS-CoV-2 reagents for the BD MAX system (MAX SARS-CoV-2 assay), the bioMérieux BioFire respiratory panel 2.1 (BioFire SARS-CoV-2 assay), the Roche cobas SARS-CoV-2 assay (cobas SARS-CoV-2 assay), and the Hologic Aptima SARS-CoV-2 assay Panther (Aptima SARS-CoV-2 assay) NAAT systems were determined using a total of 84 contrived nasopharyngeal specimens with 7 target levels for each comparator. The positive and negative percent agreement (PPA and NPA, respectively) of the MAX SARS-CoV-2 assay, compared to the Aptima SARS-CoV-2 assay, was evaluated in a postmarket clinical study utilizing 708 nasopharyngeal specimens collected from suspected COVID-19 cases. Discordant testing was achieved using the cobas and BioFire SARS-CoV-2 NAATs. In this study, the measured LOD for the MAX SARS-CoV-2 assay (251 copies/ml; 95% confidence interval [CI], 186 to 427) was comparable to the cobas SARS-CoV-2 assay (298 copies/ml; 95% CI, 225 to 509) and the BioFire SARS-CoV-2 assay (302 copies/ml; 95% CI, 219 to 565); the Aptima SARS-CoV-2 assay had an LOD of 612 copies/ml (95% CI, 474 to 918). The MAX SARS-CoV-2 assay had a PPA of 100% (95% CI, 97.3% to 100.0%) and an NPA of 96.7% (95% CI, 94.9% to 97.9%) compared to the Aptima SARS-CoV-2 assay. The clinical performance of the MAX SARS-CoV-2 assay agreed with another sensitive EUA assay.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19 Testing , Humans , Indicators and Reagents , Molecular Diagnostic Techniques , Nasopharynx , Sensitivity and Specificity
9.
J Clin Virol ; 143: 104946, 2021 10.
Article in English | MEDLINE | ID: covidwho-1433478

ABSTRACT

BACKGROUND: COVID-19 and influenza (flu) share similar clinical symptoms. Therefore, differential detection of these viruses during the respiratory virus season will be an important component for proper patient triage, management, and treatment. OBJECTIVES: Establish the diagnostic performance related to SARS-CoV-2 and Flu A/B detection for the BD SARS-CoV-2/Flu for BD MAX™ System ("MAX SARS-CoV-2/Flu") multiplex assay. MATERIALS AND METHODS: Two hundred and thirty-five (235) retrospective nasopharyngeal specimens were obtained from external vendors. The BD BioGx SARS-CoV-2 Reagents for BD MAX™ System ("BioGx SARS-CoV-2″) and the Cepheid Xpert® Xpress Flu/RSV ("Xpert Flu/RSV") were utilized as reference methods. RESULTS: By reference methods, 52 specimens were SARS-CoV-2-positive, 59 were Flu A-positive, and 60 were Flu B-positive. MAX SARS-CoV-2/Flu had positive percent agreement (PPA) and negative percent agreement (NPA) values for SARS-CoV-2 detection of 96.2% ([95%CI]:87.0-98.9) and 100% [95%CI:88.7-100], respectively; PPA values for Flu A and Flu B of 100% [95%CI:93.9-100] and 98.3% [95%CI:91.1-99.7], respectively, and NPA values for Flu A and Flu B of 98.9% [95%CI:94.0-99.8] and 100% [95%CI:95.9-100], respectively. CONCLUSIONS: The MAX SARS-CoV-2/Flu assay met FDA-EUA performance criteria for SARS-CoV-2 (≥95% for PPA and NPA) and FDA clearance criteria for Flu A/B (PPA ≥90%; lower bound of the 95%CI ≥80% and NPA ≥95%; lower bound of the 95%CI ≥90%).


Subject(s)
COVID-19 , Influenza, Human , Humans , Influenza, Human/diagnosis , Molecular Diagnostic Techniques , Nasopharynx , Retrospective Studies , SARS-CoV-2 , Sensitivity and Specificity
10.
PLoS One ; 16(9): e0253407, 2021.
Article in English | MEDLINE | ID: covidwho-1398926

ABSTRACT

Surveillance testing for infectious disease is an important tool to combat disease transmission at the population level. During the SARS-CoV-2 pandemic, RT-PCR tests have been considered the gold standard due to their high sensitivity and specificity. However, RT-PCR tests for SARS-CoV-2 have been shown to return positive results when performed to individuals who are past the infectious stage of the disease. Meanwhile, antigen-based tests are often treated as a less accurate substitute for RT-PCR, however, new evidence suggests they may better reflect infectiousness. Consequently, the two test types may each be most optimally deployed in different settings. Here, we present an epidemiological model with surveillance testing and coordinated isolation in two congregate living settings (a nursing home and a university dormitory system) that considers test metrics with respect to viral culture, a proxy for infectiousness. Simulations show that antigen-based surveillance testing coupled with isolation greatly reduces disease burden and carries a lower economic cost than RT-PCR-based strategies. Antigen and RT-PCR tests perform different functions toward the goal of reducing infectious disease burden and should be used accordingly.


Subject(s)
Antigens, Viral/immunology , COVID-19 Serological Testing/methods , COVID-19/diagnosis , SARS-CoV-2/genetics , SARS-CoV-2/immunology , COVID-19/virology , False Negative Reactions , False Positive Reactions , Humans , Immunologic Surveillance/immunology , Nursing Homes , Pandemics/prevention & control , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity , Universities
11.
Preprint in English | medRxiv | ID: ppmedrxiv-21262914

ABSTRACT

BackgroundCity-wide lockdowns and school closures have demonstrably impacted COVID-19 transmission. However, simulation studies have suggested an increased risk of COVID-19 related morbidity for older individuals inoculated by house-bound children. This study examines whether the March 2020 lockdown in New York City (NYC) was associated with higher COVID-19 hospitalization rates in neighborhoods with larger proportions of multigenerational households. MethodsWe obtained daily age-segmented COVID-19 hospitalization counts in each of 166 ZIP code tabulation areas (ZCTAs) in NYC. Using Bayesian Poisson regression models that account for spatiotemporal dependencies between ZCTAs, as well as socioeconomic risk factors, we conducted a difference-in-differences study amongst ZCTA-level hospitalization rates from February 23 to May 2, 2020. We compared ZCTAs in the lowest quartile of multigenerational housing to other quartiles before and after the lockdown. FindingsAmong individuals over 55 years, the lockdown was associated with higher COVID-19 hospitalization rates in ZCTAs with more multigenerational households. The greatest difference occurred three weeks after lockdown: Q2 vs. Q1: 54% increase (95% Bayesian credible intervals: 22 - 96%); Q3 vs. Q1: 48%, (17 - 89%); Q4 vs. Q1: 66%, (30 - 211%). After accounting for pandemic-related population shifts, a significant difference was observed only in Q4 ZCTAs: 37% (7 -76%). InterpretationBy increasing house-bound mixing across older and younger age groups, city-wide lockdown mandates imposed during the growth of COVID-19 cases may have inadvertently, but transiently, contributed to increased transmission in multigenerational households. FundingNational Center for Advancing Translational Sciences; Clinical and Translational Science Center at Weill Cornell Medical College.

12.
Diabetes ; 70, 2021.
Article in English | ProQuest Central | ID: covidwho-1362271

ABSTRACT

The COVID-19 pandemic has caused sustained disruptions in access to usual diabetes care. In response to the high number of cancelations, an academic, urban diabetes program transitioned to virtual visits and launched an initiative to provide outreach to patients who canceled an appointment between Mar 16 and Jun 19, 2020. Members of the diabetes team used a standardized approach to prevent delayed care or disengagement. Method of contact was defined as Reached (two-way communication between clinician and patient by phone or EHR portal message), Message Left (e.g., voicemail) and No Contact. Engagement was defined as booking a follow up appointment and keeping the appointment. A total of 787 patients were determined to have canceled visits due to the pandemic. Mean (SD) age was 61.7 yrs (14.2), 53.7% female, 67.3% white, baseline A1c 7.96% (1.81). Of the 648 visits booked, 519 (80%) were kept. Patients who were reached were more likely to book (OR = 2.43, p<0.001) and keep an appointment (OR = 2.39, p<0.001) compared to no contact or message left. Older age was a significant predictor of booking (OR = 1.014 for each year older, p=0.037). Patients on insulin were more likely to keep their appointment (OR = 1.70, p=0.008), while patients with higher HbA1c were less likely to (OR = 0.87 for each 1.0% increase in HbA1c, p=0.011). These findings suggest that for systems designed to optimize engagement during care disruption, one-way communication is no better than no contact, and two-way communication increases the likelihood that patients will maintain access to care. In addition, while higher risk patients (e.g., older age or on insulin) may be more incentivized to stay engaged, targeted outreach may be needed for those with chronic poor glycemic control.

13.
Preprint in English | medRxiv | ID: ppmedrxiv-21258248

ABSTRACT

Surveillance testing for infectious disease is an important tool to combat disease transmission at the population level. During the SARS-CoV-2 pandemic, RT-PCR tests have been considered the gold standard due to their high sensitivity and specificity. However, RT-PCR tests for SARS-CoV-2 have been shown to return positive results when administered to individuals who are past the infectious stage of the disease. Meanwhile, antigen-based tests are often treated as a less accurate substitute for RT-PCR, however, new evidence suggests they may better reflect infectiousness. Consequently, the two test types may each be most optimally deployed in different settings. Here, we present an epidemiological model with surveillance testing and coordinated isolation in two congregate living settings (a nursing home and a university dormitory system) that considers test metrics with respect to viral culture, a proxy for infectiousness. Simulations show that antigen-based surveillance testing coupled with isolation greatly reduces disease burden and carries a lower economic cost than RT-PCR-based strategies. Antigen and RT-PCR tests perform different functions toward the goal of reducing infectious disease burden and should be used accordingly.

14.
Journal of Agriculture Food Systems and Community Development ; 10(2):241-245, 2021.
Article in English | Web of Science | ID: covidwho-1244310

ABSTRACT

The novel coronavirus pandemic has had an immediate effect on food and nutrition security, leading to the most widespread increase in need for food assistance in modern history. At its onset, the pandemic led to emergency food providers experiencing the "perfect storm": surges in demand, declines and changes in types of food donations, limits in the food supply chain, and fewer available volunteers. This policy and practice brief provides perspectives from emergency food providers in North Carolina on their pandemic response along with recommendations for policy and practice applications to promote food security. As the pandemic continues, it is urgent for policymakers, organizations, community members, and other food system stakeholders to encourage collaboration across food system sectors, provide adequate funding for all aspects of distributing healthy foods, promote a continuation of program and policy flexibilities for nutrition programs, and support community-based models that engage a diverse group of organizations and leaders.

15.
Preprint in English | medRxiv | ID: ppmedrxiv-21257181

ABSTRACT

Tests that detect the presence of SARS-CoV-2 antigen in clinical specimens from the upper respiratory tract can provide a rapid means of COVID-19 disease diagnosis and help identify individuals that may be infectious and should isolate to prevent SARS-CoV-2 transmission. This systematic review assesses the diagnostic accuracy of SARS-CoV-2 antigen detection in COVID-19 symptomatic and asymptomatic individuals compared to RT-qPCR, and summarizes antigen test sensitivity using meta-regression. In total, 83 studies were included that compared SARS-CoV-2 rapid antigen lateral flow testing (RALFT) to RT-qPCR for SARS-CoV-2. Generally, the quality of the evaluated studies was inconsistent, nevertheless, the overall sensitivity for RALFT was determined to be 75.0% (95% confidence interval [CI]: 71.0-78.0). Additionally, RALFT sensitivity was found to be higher for symptomatic versus asymptomatic individuals and was higher for a symptomatic population within 7 days from symptom onset (DSO) compared to a population with extended days of symptoms. Viral load was found to be the most important factor for determining SARS-CoV-2 antigen test sensitivity. Other design factors, such as specimen storage and anatomical collection type, also affect the performance of RAFLT. RALFT and RT-qPCR testing both achieve high sensitivity when compared to SARS-CoV-2 viral culture.

16.
Preprint in English | medRxiv | ID: ppmedrxiv-21251915

ABSTRACT

Efficient and accurate assays for the differential diagnosis of COVID-19 and/or influenza (flu) could facilitate optimal treatment for both diseases. Diagnostic performance related to SARS-CoV-2 and Flu A/B detection was characterized for the BD SARS-CoV-2/Flu for BD MAX System ("MAX SARS-CoV-2/Flu") multiplex assay in comparison with BD BioGx SARS-CoV-2 Reagents for BD MAX System ("BioGx SARS-CoV-2") and the Cepheid Xpert(R) Xpress Flu/RSV ("Xpert Flu"). Two hundred and thirty-five nasopharyngeal specimens were obtained from external vendors. MAX SARS-CoV-2/Flu had positive percent agreement (PPA) and negative percent agreement (NPA) values for SARS-CoV-2 and Flu A/B that met FDA-EUA acceptance criteria of >95%.

17.
Clin Infect Dis ; 73(9): e2861-e2866, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1043631

ABSTRACT

BACKGROUND: Individuals can test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by molecular assays following the resolution of their clinical disease. Recent studies indicate that SARS-CoV-2 antigen-based tests are likely to be positive early in the disease course, when there is an increased likelihood of high levels of infectious virus. METHODS: Upper respiratory specimens from 251 participants with coronavirus disease 2019 symptoms (≤7 days from symptom onset) were prospectively collected and tested with a lateral flow antigen test and a real-time polymerase chain reaction (rt-PCR) assay for detection of SARS-CoV-2. Specimens from a subset of the study specimens were utilized to determine the presence of infectious virus in the VeroE6TMPRSS2 cell culture model. RESULTS: The antigen test demonstrated a higher positive predictive value (90%) than rt-PCR (70%) when compared to culture-positive results. The positive percentage agreement for detection of infectious virus for the antigen test was similar to rt-PCR when compared to culture results. CONCLUSIONS: The correlation between SARS-CoV-2 antigen and SARS-CoV-2 culture positivity represents a significant advancement in determining the risk for potential transmissibility beyond that which can be achieved by detection of SARS-CoV-2 genomic RNA. SARS-CoV-2 antigen testing can facilitate low-cost, scalable, and rapid time-to-result, while providing good risk determination of those who are likely harboring infectious virus, compared to rt-PCR.


Subject(s)
COVID-19 , SARS-CoV-2 , Antigens, Viral , Humans , Real-Time Polymerase Chain Reaction , Sensitivity and Specificity
19.
J Clin Microbiol ; 59(1)2020 12 17.
Article in English | MEDLINE | ID: covidwho-991754

ABSTRACT

The clinical performance of the BD Veritor System for Rapid Detection of SARS-CoV-2 nucleocapsid antigen (Veritor), a chromatographic immunoassay used for SARS-CoV-2 point-of-care testing, was evaluated using nasal specimens from individuals with COVID-19 symptoms. Two studies were completed to determine clinical performance. In the first study, nasal specimens and either nasopharyngeal or oropharyngeal specimens from 251 participants with COVID-19 symptoms (≤7 days from symptom onset [DSO], ≥18 years of age) were utilized to compare Veritor with the Lyra SARS-CoV-2 PCR assay (Lyra). In the second study, nasal specimens from 361 participants with COVID-19 symptoms (≤5 DSO, ≥18 years of age) were utilized to compare performance of Veritor to that of the Sofia 2 SARS Antigen FIA test (Sofia 2). The positive, negative, and overall percent agreement (PPA, NPA, and OPA, respectively) were the primary outcomes. In study 1, the PPA for Veritor, compared to Lyra, ranged from 81.8 to 87.5% across the 0 to 1 and 0 to 6 DSO ranges. In study 2, Veritor had PPA, NPA, and OPA values of 97.4, 98.1, and 98.1%, respectively, with Sofia 2. Discordant analysis showed one Lyra positive missed by Veritor and five Lyra positives missed by Sofia 2; one Veritor positive result was negative by Lyra. Veritor met FDA emergency use authorization (EUA) acceptance criteria for SARS-CoV-2 antigen testing for the 0 to 5 and 0 to 6 DSO ranges (PPA values of 83.9% and 82.4%, respectively). Veritor and Sofia 2 showed a high degree of agreement for SARS-CoV-2 detection. The Veritor test allows for more rapid COVID-19 testing utilizing easy-to-collect nasal swabs but demonstrated <100% PPA compared to PCR.


Subject(s)
Antigens, Viral/analysis , COVID-19 Testing/methods , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/analysis , Spike Glycoprotein, Coronavirus/analysis , Adult , Female , Humans , Immunoassay/methods , Male , Middle Aged , Nasopharynx/virology , Oropharynx/virology , Point-of-Care Testing , Polymerase Chain Reaction/methods , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Sensitivity and Specificity
20.
Russian Journal of Agricultural and Socio Economic Sciences ; 7(103):113-119, 2020.
Article in English | CAB Abstracts | ID: covidwho-830757

ABSTRACT

Horticultural food commodities such as shallots are a staple and strategic commodity in Indonesia which is affected by the covid-19 pandemic situation. This study is to answer the pattern of price movements and disparities, as well as the level of fluctuations in the price of shallots due to the covid-19 pandemic in traditional markets in Kupang and Surabaya. Kupang NTT as the recipient of shallots supplies from Surabaya, East Java. Using time-series data of the shallot prices for the period of June 2016 - March 2020 to see disparities and fluctuations, which analyzed using graphics and coefficient of variation (CV). The results of the analysis found that the disparity and fluctuations of the price of shallots between the periods of June 2016 - March 2020, showed a movement that continues to increase, but with a fluctuating increase. Price disparity and fluctuation in Kupang is higher than in Surabaya. This difference is in addition to the seasonal factor also because Surabaya is one of the main suppliers of shallots to Kupang. So that the prices sensitively will rise if there is a disruption in distribution (supply). This seems clear when the initial enactment of social distancing and panic buying took place. Market operations and policies to improve efficiency in the distribution of trade in goods need attention.

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