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1.
Clin Lab Med ; 42(2): 203-222, 2022 06.
Article in English | MEDLINE | ID: covidwho-2130437

ABSTRACT

Though rapid antigen tests have historically problematic performance characteristics for the diagnosis of respiratory viral infections such as influenza, they have attained an unprecedented level of use in the context of the COVID-19 pandemic. Ease of use and scalability of rapid antigen tests has facilitated a democratization and scale of testing beyond anything reasonably achievable by traditional laboratory-based testing. In this chapter, we discuss the performance characteristics of rapid antigen testing for SARS-CoV-2 detection and their application to non-traditional uses beyond clinical diagnostic testing.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Humans , Immunologic Tests , Pandemics
2.
PLoS One ; 17(11): e0273107, 2022.
Article in English | MEDLINE | ID: covidwho-2140473

ABSTRACT

BACKGROUND: The global coronavirus disease 2019 (COVID-19) has presented significant challenges and created concerns worldwide. Besides, patients who have experienced a SARS-CoV-2 infection could present post-viral complications that can ultimately lead to pulmonary fibrosis. Serum levels of Krebs von den Lungen 6 (KL-6), high molecular weight human MUC1 mucin, are increased in the most patients with various interstitial lung damage. Since its production is raised during epithelial damages, KL-6 could be a helpful non-invasive marker to monitor COVID-19 infection and predict post-infection sequelae. METHODS: We retrospectively evaluated KL-6 levels of 222 COVID-19 infected patients and 70 healthy control. Serum KL-6, fibrinogen, lactate dehydrogenase (LDH), platelet-lymphocytes ratio (PLR) levels and other biological parameters were analyzed. This retrospective study also characterized the relationships between serum KL-6 levels and pulmonary function variables. RESULTS: Our results showed that serum KL-6 levels in COVID-19 patients were increased compared to healthy subjects (470 U/ml vs 254 U/ml, P <0.00001). ROC curve analysis enabled us to identify that KL-6 > 453.5 U/ml was associated with COVID-19 (AUC = 0.8415, P < 0.0001). KL-6 level was positively correlated with other indicators of disease severity such as fibrinogen level (r = 0.1475, P = 0.0287), LDH level (r = 0,31, P = 0,004) and PLR level (r = 0.23, P = 0.0005). However, KL-6 levels were not correlated with pulmonary function tests (r = 0.04, P = 0.69). CONCLUSIONS: KL-6 expression was correlated with several disease severity indicators. However, the association between mortality and long-term follow-up outcomes needs further investigation. More extensive trials are required to prove that KL-6 could be a marker of disease severity in COVID-19 infection.


Subject(s)
COVID-19 , Humans , Retrospective Studies , SARS-CoV-2 , Immunologic Tests , Fibrinogen
4.
Sensors (Basel) ; 22(19)2022 Sep 28.
Article in English | MEDLINE | ID: covidwho-2066350

ABSTRACT

Due to the recent pandemic caused by coronavirus disease 2019 (COVID-19), the lateral flow immunoassay used for its rapid antigen test is more popular than ever before. However, the history of the lateral flow immunoassay is about 60 years old, and its original purpose of use, such as a COVID-19 rapid antigen test or a pregnancy test, was the qualitative detection of a target analyte. Recently, the demand for quantitative analysis of lateral flow immunoassays is increasing in various fields. Lateral flow immunoassays for quantitative detection using various materials and sensor technologies are being introduced, and readers for analyzing them are being developed. Quantitative analysis readers are highly anticipated for their future development in line with technological advancements such as optical, magnetic field, photothermal, and electrochemical sensors and trends such as weight reduction, miniaturization, and cost reduction of systems. In addition, the sensing, processing, and communication functions of portable personal devices such as smartphones can be used as tools for the quantitative analysis of lateral flow immunoassays. As a result, lateral flow immunoassays can efficiently achieve the goal of rapid diagnosis by point-of-care testing. Readers used for the quantification of lateral flow immunoassays were classified according to the adopted sensor technology, and the research trends in each were reviewed in this paper. The development of a quantitative analysis system was often carried out in the assay aspect, so not only the readers but also the assay development cases were reviewed if necessary. In addition, systems for quantitative analysis of COVID-19, which have recently been gaining importance, were introduced as a separate section.


Subject(s)
COVID-19 , COVID-19/diagnosis , Humans , Immunoassay/methods , Immunologic Tests , Middle Aged , Miniaturization , Point-of-Care Systems , Point-of-Care Testing
6.
J Infect Dis ; 226(11): 1903-1908, 2022 Nov 28.
Article in English | MEDLINE | ID: covidwho-1997060

ABSTRACT

In this population-based cohort of 7538 adults, combined immunoglobulin (Ig) G, IgA, and IgM (IgG/A/M) anti-spike titers measured after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination were predictive of protection against breakthrough SARS-CoV-2 infection. Discrimination was significantly improved by adjustment for factors influencing risk of SARS-CoV-2 exposure, including household overcrowding, public transport use, and visits to indoor public places. Anti-spike IgG/A/M titers showed positive correlation with neutralizing antibody titers (rs = 0.80 [95% confidence interval, .72-.86]; P < .001) and S peptide-stimulated interferon-γ concentrations (rs = 0.31 [.13-.47]; P < .001).


Subject(s)
COVID-19 , Adult , Humans , COVID-19/prevention & control , SARS-CoV-2 , Longitudinal Studies , Immunologic Tests , Immunoglobulin G , Antibodies, Viral
7.
J Med Virol ; 94(10): 5033-5037, 2022 10.
Article in English | MEDLINE | ID: covidwho-1981839

ABSTRACT

The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) Omicron was classified as a variant of concern in November 2021. The sublineage BA.2 spreads rapidly worldwide. Currently, there is a lack of data for the parallel comparison of Rapid Antigen Test (RAT) Kits to detect SARS-CoV-2 Omicron BA.2. We evaluated the analytical sensitivity of 12 RAT kits to detect Omicron BA.2 in the present study. Analytical sensitivity was determined by means of the limit of detection (LOD). We prepared a dilution set using a respiratory specimen collected from a COVID-19 patient infected by Omicron BA.2. The reverse transcription-polymerase chain reaction was used as a reference method. The LOD results showed that all 12 RAT kits had comparable analytical sensitivity to detect Omicron BA.2. The RAT kits selected in the current study may be used for the first-line screening of the rapid spreading Omicron BA.2.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Humans , Immunologic Tests , RNA, Viral/analysis , SARS-CoV-2/genetics
8.
Viruses ; 14(8)2022 07 28.
Article in English | MEDLINE | ID: covidwho-1969497

ABSTRACT

The diagnostic of SARS-CoV-2 infection relies on reverse transcriptase polymerase chain reactions (RT-PCRs) performed on nasopharyngeal (NP) swabs. Nevertheless, false-negative results can be obtained with inadequate sampling procedures, making the use of other biological matrices worthy of investigation. This study aims to evaluate the kinetics of serum N antigens in severe and non-severe patients and compare the clinical performance of serum antigenic assays with NP RT-PCR. Ninety patients were included in the study and monitored for several days. Disease severity was determined according to the WHO clinical progression scale. Serum N antigen levels were measured with a chemiluminescent assay (CLIA) and the Single Molecular Array (Simoa) assay. Viremia thresholds for severity were determined and proposed. In severe patients, the peak antigen response was observed 7 days after the onset of symptoms, followed by a decline. No real peak response was observed in non-severe patients. Severity thresholds for the Simoa and the CLIA provided positive likelihood ratios of 30.0 and 10.9 for the timeframe between day 2 and day 14, respectively. Sensitive detection of N antigens in serum may thus provide a valuable new marker for COVID-19 diagnosis and evaluation of disease severity. When assessed during the first 2 weeks since the onset of symptoms, it may help in identifying patients at risk of developing severe COVID-19 to optimize better intensive care utilization.


Subject(s)
COVID-19 , COVID-19/diagnosis , COVID-19 Testing , Humans , Immunologic Tests , SARS-CoV-2 , Sensitivity and Specificity , Severity of Illness Index
9.
Int J Mol Sci ; 23(14)2022 Jul 12.
Article in English | MEDLINE | ID: covidwho-1964003

ABSTRACT

The mosquito-borne disease caused by the Rocio virus is a neglected threat, and new immune inputs for serological testing are urgently required for diagnosis in low-resource settings and epidemiological surveillance. We used in silico approaches to identify a specific antigenic peptide (p_ROCV2) in the NS1 protein of the Rocio virus that was theoretically predicted to be stable and exposed on its surface, where it demonstrated key properties allowing it to interact with antibodies. These findings related to the molecular dynamics of this peptide provide important insights for advancing diagnostic platforms and investigating therapeutic alternatives.


Subject(s)
Flavivirus , Molecular Dynamics Simulation , Animals , Immunologic Tests , Molecular Docking Simulation , Peptides , Viral Nonstructural Proteins/chemistry
11.
PLoS One ; 17(3): e0264929, 2022.
Article in English | MEDLINE | ID: covidwho-1938420

ABSTRACT

BACKGROUND: People experiencing homelessness who live in congregate shelters are at high risk of SARS-CoV2 transmission and severe COVID-19. Current screening and response protocols using rRT-PCR in homeless shelters are expensive, require specialized staff and have delays in returning results and implementing responses. METHODS: We piloted a program to offer frequent, rapid antigen-based tests (BinaxNOW) to residents and staff of congregate-living shelters in San Francisco, California, from January 15th to February 19th, 2021. We used the Reach-Effectiveness-Adoption-Implementation-Maintenance (RE-AIM) framework to evaluate the implementation. RESULTS: Reach: We offered testing at ten of twelve eligible shelters. Shelter residents and staff had variable participation across shelters; approximately half of eligible individuals tested at least once; few tested consistently during the study. Effectiveness: 2.2% of participants tested positive. We identified three outbreaks, but none exceeded 5 cases. All BinaxNOW-positive participants were isolated or left the shelters. Adoption: We offered testing to all eligible participants within weeks of the project's initiation. Implementation: Adaptations made to increase reach and improve consistency were promptly implemented. Maintenance: San Francisco Department of Public Health expanded and maintained testing with minimal support after the end of the pilot. CONCLUSION: Rapid and frequent antigen testing for SARS-CoV2 in homeless shelters is a viable alternative to rRT-PCR testing that can lead to immediate isolation of infectious individuals. Using the RE-AIM framework, we evaluated and adapted interventions to enable the expansion and maintenance of protocols.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , Homeless Persons/statistics & numerical data , COVID-19/immunology , COVID-19 Testing/methods , California , Disease Outbreaks/prevention & control , Housing , Humans , Immunologic Tests/methods , Mass Screening/methods , Pilot Projects , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , San Francisco
12.
Methods Mol Biol ; 2524: 235-248, 2022.
Article in English | MEDLINE | ID: covidwho-1930204

ABSTRACT

Reporter-expressing recombinant severe acute respiratory syndrome coronavirus 2 (rSARS-CoV-2) represents an excellent tool to understand the biology of and ease studying viral infections in vitro and in vivo. The broad range of applications of reporter-expressing recombinant viruses is due to the facilitated expression of fluorescence or bioluminescence readouts. In this chapter, we describe a detailed protocol on the generation of rSARS-CoV-2 expressing Venus, mCherry, and NLuc that represents a valid surrogate to track viral infections.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Immunologic Tests , Respiratory System , SARS-CoV-2/genetics
13.
Cell Rep Med ; 3(6): 100663, 2022 06 21.
Article in English | MEDLINE | ID: covidwho-1900277

ABSTRACT

Post-acute sequelae of COVID-19 (PASC) is emerging as global problem with unknown molecular drivers. Using a digital epidemiology approach, we recruited 8,077 individuals to the cohort study for digital health research in Germany (DigiHero) to respond to a basic questionnaire followed by a PASC-focused survey and blood sampling. We report the first 318 participants, the majority thereof after mild infections. Of those, 67.8% report PASC, predominantly consisting of fatigue, dyspnea, and concentration deficit, which persists in 60% over the mean 8-month follow-up period and resolves independently of post-infection vaccination. PASC is not associated with autoantibodies, but with elevated IL-1ß, IL-6, and TNF plasma levels, which we confirm in a validation cohort with 333 additional participants and a longer time from infection of 10 months. Blood profiling and single-cell data from early infection suggest the induction of these cytokines in COVID-19 lung pro-inflammatory macrophages creating a self-sustaining feedback loop.


Subject(s)
COVID-19 , Cytokines , COVID-19/complications , COVID-19/immunology , COVID-19/pathology , Cohort Studies , Cytokines/immunology , Disease Progression , Humans , Immunologic Tests , Interleukin-1beta/immunology , Interleukin-6/immunology , Tumor Necrosis Factor-alpha/immunology
14.
Sci Rep ; 12(1): 8811, 2022 05 25.
Article in English | MEDLINE | ID: covidwho-1864764

ABSTRACT

In response to the COVID-19 pandemic, lateral flow assays (LFAs) for the detection of SARS-CoV-2 antigen have been proposed as a complementary option to the more costly and time consuming reverse-transcriptase polymerase chain reaction (RT-PCR). We assessed five commercially available SARS-CoV-2 antigen detecting LFAs (ASSUT EUROPE (Rome, Italy), Besthree (Taizhou, China), Encode (Zhuhai, China), Fortress (Antrim UK), and Hughes Medical (Buckinghamshire, UK), using samples collected from hospitalised individuals with COVID-19 and compared these results against established RT-PCR assays with the aim of estimating test performance characteristics. We performed a diagnostic accuracy study of the five LFAs on 110 inpatients with confirmed COVID-19 and 75 COVID-19 negative control participants. Assay evaluation was performed using a modified version of each manufacturer's protocol allowing for parallel testing of a single sample on multiple assays. Additional variables were studied including infection acquisition, oxygenation requirements at time of swabbing, and patient outcomes. The 110 patients were 48% (53) female, with mean age 67 years (range 26-100 years), and 77% (85) cases were community onset SARS-CoV-2. Across the five assays, sensitivity ranged from 64 (95% CI 53-73) to 76% (95% CI 65-85); Fortress performed best with sensitivity of 76% (95% CI 65-85). Specificity was high across all assays with 4/5 LFAs achieving 100%. LFA sensitivity was not dependant on RT-PCR cycle thresholds. SARS-CoV-2 antigen detecting LFAs may complement RT-PCR testing to facilitate early diagnosis and provide community testing strategies for identification of patients with COVID-19, however we find suboptimal test performance characteristics across a range of commercially available manufacturers, below WHO and MHRA pre-set sensitivity performance thresholds. With such variation in sensitivity between LFAs and PCR testing and between assay brands, we advise caution in the deployment of LFAs outside of environments with clinical oversight.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Aged , Aged, 80 and over , COVID-19/diagnosis , Female , Humans , Immunologic Tests , Middle Aged , Nucleocapsid , Pandemics , SARS-CoV-2/genetics , Sensitivity and Specificity
17.
Front Immunol ; 13: 864775, 2022.
Article in English | MEDLINE | ID: covidwho-1862607

ABSTRACT

The SARS-CoV-2 pandemic and particularly the emerging variants have deepened the need for widely available therapeutic options. We have demonstrated that hexamer-enhancing mutations in the Fc region of anti-SARS-CoV IgG antibodies lead to a noticeable improvement in IC50 in both pseudo and live virus neutralization assay compared to parental molecules. We also show that hexamer-enhancing mutants improve C1q binding to target surface. To our knowledge, this is the first time this format has been explored for application in viral neutralization and the studies provide proof-of-concept for the use of hexamer-enhanced IgG1 molecules as potential anti-viral therapeutics.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Immunoglobulin G/genetics , Immunologic Tests , Pandemics , SARS-CoV-2/genetics
19.
Braz. arch. biol. technol ; 64(spe): e21200147, 2021. tab, graf
Article in English | WHO COVID, LILACS (Americas) | ID: covidwho-1841192

ABSTRACT

Abstract With the COVID-19 pandemic, many diagnostic tests (molecular or immunological) were rapidly standardised, given the urgency of the situation, many are still in the process of being validated. The main objective of this study was to review the aspects of the diagnostic kits approved in Brazil and their application in the different federative units to gather epidemiological information. In order to achieve these objectives, a survey was carried out on the data available at the regulatory agency (ANVISA) and in the literature. The main countries that have registered products in Brazil are China (51.4%), Brazil (16.6%), South Korea (9.2%), USA (8.8%) and Germany (3.6%). The methodologies of these products are based on the detection of nucleic-acid (15.8%), antigen (13%) and antibody (71.2%). In the immunological tests, it was verified that the sensitivity ranged from 55 to 100% and the specificity from 80 to 100%. The percentage of cases in the samples tested in Brazil is elevated in almost all federative units since eight states showed 40% of positive cases in tested samples, while 18 states displayed between 20 and 40%. In conclusion, this review showed that Brazil is dependent on external technology to respond to pandemics, epidemics and endemics disease and needs to improve its biotechnological scheme to solve further diseases outbreaks.


Subject(s)
Humans , SARS Virus/isolation & purification , COVID-19/diagnosis , Immunologic Tests/instrumentation , Brazil/epidemiology , Enzyme-Linked Immunosorbent Assay/instrumentation , Chromatography, Affinity/instrumentation , COVID-19 Testing/instrumentation , COVID-19 Nucleic Acid Testing/methods
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