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BACKGROUND: Pregnant women are vulnerable against COVID-19 infection due to physiological and immunological changes. COVID-19 in pregnancy affects fetal well-being with a potential for vertical infection. AIM: This study aims to determine the incidence of vertical infection and anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in infants born to mothers with positive COVID-19 infection. MATERIALS AND METHODS: Amniotic fluid, swabs of the newborn's nasopharynx and oropharynx, and swabs of the placenta were examined using reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. Serological examination was performed by Electro-Chemiluminescence Immunoassay on infant's blood. RESULT(S): Four of 33 pregnant women gave birth to infants positive SARS-CoV-2 infection. RT-PCR examination of all amniotic fluid and placental swabs was negative for SARS-CoV-2. Four of 33 infants (12.1%) showed negative polymerase chain reaction (PCR) results but positive SARS-CoV-2 antibodies, another 4 newborns (12.1%) showed positive PCR results, but no SARS-CoV-2 antibodies detected. The remaining 25 babies (75.8%) showed both negative PCR and serologic results. CONCLUSION(S): No evidence of vertical transmission found in this study.Copyright © 2023 Cut Meurah Yeni, Zinatul Hayati, Sarjani M. Ali, Hasanuddin Hasanuddin, Rusnaidi Rusnaidi, Cut Rika Maharani.
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Problem: Despite being over 3 years into the pandemic, infants remain highly undervaccinated and at a high risk for hospitalization due to COVID-19. Further investigation as to how maternal health decisions for immunization can reduce morbidity from infant COVID-19 by providing passive immunity is necessary. The objective of this study was to describe the rates of SARS-CoV-2 variant antibody transfer from mother to infant cord blood by trimester ofmaternal vaccination. Methods of study: This is an observational cohort study including mother-infant dyads receiving primary or subsequent booster COVID- 19 vaccines during pregnancy.Unvaccinated, but SARS-CoV-2 infected dyads with were included as a comparison group. We quantified median titer and interquartile range (IQR) for SARS-CoV-2 receptor binding domain (RBD) IgG in infant cord blood samples at delivery using the mesoscale discovery platform (electrochemiluminescence). Primary outcome was infant cord IgG titer by trimester of vaccination for the WA1/2022 RBD IgG and current circulating, immune evasive XBB RBD IgG. Secondary outcome is the percent detectable IgG for each variant. Sensitivity analysis was performed based on known SARS-CoV-2 infection. Result(s): Eighty-three mother-infant dyads were included in this analysis. Seven were vaccinated in the first trimester, 37 in the second trimester, 33 in the third trimester, and 6 were unvaccinated and infected. Twenty-three (30%) of the vaccinated group had known SARS-CoV-2 infection. Most received monovalent mRNA COVID-19 vaccines during pregnancy, aside from two who received the viralvectored Ad26.COV2.S, and two received the bivalent mRNA vaccine during pregnancy. The median cord blood WA1/2020 RBD IgG titer was 5370 (412-7296) for first, 1225 (589-3289) for second, 2623 (664-5809) for third trimester in individuals who received aCOVID-19 vaccine dose during pregnancy, and 45 (10-187) in those unvaccinated and infected. After excluding thosewith infection, the cord blood IgG was 514 (106-4182), 1070 (518-2317), and 2477 (664-4470) for first, second, and third trimester, respectively. The rate of detectable WA1/2020 RBD IgG was 100% for all three trimesters, even when excluding infected individuals. For theXBBvariant, cord bloodRBDIgG titer was 284 (43-1296) for first, 66 (32-227) for second, 173 (45-389) for third trimester, and 10 (10-11) in the unvaccinated/infected group. Excluding infections, the cord blood XBB RBD IgG was 54 (10-128), 44 (25-181), and 152 (45-360) for first, second, and third trimester vaccination, respectively. The rate of detectable XBB IgG in those who received a vaccine during pregnancy were 83%, 91%, and 90% for first, second, and third trimester respectively, compared to 17% in the unvaccinated/infected group. Excluding infections, the rate of XBB RBD IgG detection was 66%, 89%, and 95% for first, second, and third trimester vaccination, respectively. Conclusion(s): Vaccination during pregnancy leads to high rates of detectable cord blood IgG specific to SARS-CoV-2 WA1/2020 variant and current circulating variants (XBB), regardless of trimester of vaccination. Infection history leads to higher cord blood IgG in vaccinated;however, infection alone without vaccination leads to lower titer and greater rates of undetectable cord IgG at delivery.
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Background: COVID-19 in Africa was less severe with fewer reported cases, hospitalizations and deaths compared to other continents. However, the lack of adequate surveillance systems in Africa makes estimating the burden of infection challenging. Serosurveillance can aid in determining the frequency of infection within this population. This study is aimed to estimate SARS-CoV-2 seroprevalence, describe the SARS-CoV-2 antibody (Ab) levels, and examine associations of seroreactivity among Ugandan blood donors. Method(s): Samples were obtained from the Mirasol Evaluation of Reduction in Infections Trial (MERIT), a randomized, double blind, controlled clinical trial evaluating transfusion transmitted infections. MERIT blood donor samples (n=3,517) were collected from Kampala, Uganda between October 2019 to April 2022. Additional blood donor samples (n=1,876) were collected from around the country between November-December 2021. Samples were tested for Ab to SARS-CoV-2 nucleocapsid (N) and spike (S) using an electrochemiluminescence immunoassay assay (Meso Scale Diagnostics, Gaithersburg, MD) per manufacturer's protocol. Samples seroreactive to both N and S Ab were considered Ab positive to SARS-CoV-2. Seroprevalence among MERIT donors were estimated within each quarter. Factors associated with seroreactivity from November-December 2021 were assessed by chi-square test. Result(s): SARS-CoV-2 seroprevalence increased from < 2.0% in October 2019- June 2020 to 82.5% in January-April 2022. Three distinct peaks in seroreactivity were seen in October-November 2020, July-August 2021, and January-April 2022 (see Figure). Among seroreactive donors, median N Ab levels increased 9-fold and median S Ab 19-fold over the study period. In November-December 2021, SARS-CoV-2 seroprevalence was higher among donors from Kampala (58.8%) compared to more rural regions of Hoima (47.7%), Jinja (47.9%), and Masaka (54.4%;p=0.007);S seroprevalence was lower among HIV+ donors (58.8% vs. 84.9%;p=0.009). Conclusion(s): Blood donors in Uganda showed high prevalence of Ab to SARSCoV- 2 by March of 2022, indicating that the infection levels were similar to many other regions of the globe. Higher seroprevalence was observed in the capital compared to more rural areas in Uganda. Further, increasingly high antibody levels among seropositive donors may indicate repeat infections. The lower COVID-19 morbidity and mortality was not due to a lack of exposure of the virus, but other factors yet to be determined.
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Objective: The reverse transcription-polymerase chain reaction test (RT-PCR) is the gold standard for the diagnosis of coronavirus disease 2019 (COVID-19), and antibody tests are useful as supplemental tools for diagnosis, for measuring the population's immunity levels, and for checking infection in asymptomatic contacts. This study aimed to evaluate the reliability of five commercial antibody detection test kits. Materials and Methods: The reliability of the Colloidal Gold COVID-19 IgG/IgM Rapid Test Kit, Antibody Rapid Test Hotgen, Beijing Hotgen Biotech Co., Ltd., China), Abbott Chemiluminescent Microparticle Immunoassay (Illinois, USA), Roche Electrochemiluminescence Immunoassay (Roche Diagnostics, Switzerland), Siemens Chemiluminescence (Munich, Germany), and Euroimmun ELISA (Lubeck, Germany) for COVID-19 diagnosis was studied. The antibody-negative group included 50 sera from 2018, and the antibody-positive group included 98 patients with positive RT-PCR results from whom blood samples had been collected 3-9 weeks after hospital discharge. Statistical analysis was performed using SPSS version 23.0 (IBM Corporation, Armonk, NY, USA). The antibody tests' validity and intra-assay reproducibility were examined, and the Cohen's kappa coefficients were obtained. The disease prevalence was pegged at 10%. Results: The antibody tests' sensitivity (69.12-72.46%) and positive predictive values (42.44-100.0%) were low, and their specificity (89.58-100%) and negative predictive values (96.31-97.03%) were high. Their accuracy rates varied from 87.54% to 97.25%, and their intra-assay coefficients of variation varied from 1% to 10%. Conclusion: The agreement between the results of the antibody detection test kits was higher when the kits were classified according to the targeted antigens. The time of blood sample collection, targeted antigens, and antibody types affected the results. Serological tests were found to be useful, and the commercial kits were found to be largely reliable, although, some parameters need to be improved.
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The occurrence of sudden viral outbreaks, including (Covid-19, H1N1 flu, H5N1 flu) has globally challenged the existing medical facilities and raised critical concerns about saving affected lives, especially during pandemics. The detection of viral infections at an early stage using biosensors has been proven to be the most effective, economical, and rapid way to combat their outbreak and severity. However, state-of-the-art biosensors possess bottlenecks of long detection time, delayed stage detection, and sophisticated requirements increasing the cost and complexities of biosensing strategies. Recently, using two-dimensional MXenes as a sensing material for architecting biosensors has been touted as game-changing technology in diagnosing viral diseases. The unique surface chemistries with abundant functional terminals, excellent conductivity, tunable electric and optical attributes and high specific surface area have made MXenes an ideal material for architecting virus-diagnosing biosensors. There are numerous detecting modules in MXene-based virus-detecting biosensors based on the principle of detecting various biomolecules like viruses, enzymes, antibodies, proteins, and nucleic acid. This comprehensive review critically summarizes the state-of-the-art MXene-based virus-detecting biosensors, their limitations, potential solutions, and advanced intelligent prospects with the integration of internet-of-things, artificial intelligence, 5G communications, and cloud computing technologies. It will provide a fundamental structure for future research dedicated to intelligent and point-of-care virus detection biosensors.
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A novel immunosensor based on electrochemiluminescence resonance energy transfer (ECL-RET) for the sensitive determination of N protein of the SARS-CoV-2 coronavirus is described. For this purpose, bifunctional core@shell nanoparticles composed of a Pt-coated Au core and finally decorated with small Au inlays (Au@Pt/Au NPs) have been synthesized to act as ECL acceptor, using [Ru (bpy)3]2+ as ECL donor. These nanoparticles are efficient signaling probes in the immunosensor developed. The proposed ECL-RET immunosensor has a wide linear response to the concentration of N protein of the SARS-CoV-2 coronavirus with a detection limit of 1.27 pg/mL. Moreover, it has a high stability and shows no response to other proteins related to different virus. The immunosensor has achieved the quantification of N protein of the SARS-CoV-2 coronavirus in saliva samples. Results are consistent with those provided by a commercial colorimetric ELISA kit. Therefore, the developed immunosensor provides a feasible and reliable tool for early and effective detection of the virus to protect the population.
Subject(s)
Biosensing Techniques , COVID-19 , Metal Nanoparticles , Humans , Gold , SARS-CoV-2 , Luminescent Measurements/methods , Biosensing Techniques/methods , Immunoassay/methods , COVID-19/diagnosis , Electrochemical Techniques/methods , Limit of DetectionABSTRACT
Background: According to data from the World Health Organization updated to September 30, 2022, SARS-CoV-2 is a viral disease, that infected six hundred million people and claimed six and a half million victims in all over the world. Some authors describe the alteration of blood parameters in pediatric age following COVID-19 such as: anomalies of the leukocyte formula, CK-MB and LDH enzymes, C reactive protein (PCR) and procalcitonin (PCT). Based on these studies we wanted to focus on two cardiac biomarkers: type B natriuretic peptide (BNP) and high sensitivity cardiac troponin (cTnT-hs). In order to suggest a strategy aimed at preventing the possible occurrence of cardiovascular complications in children we monitored them in patients with specific anti-SARS-CoV-2 immunoglobulins (IgG). Method(s): From November 2020 to December 2021, 53 children with positive IgG to SARS-CoV-2 by immunochromatographic method were tested for BNP and cTnT-hs. Samples collected in potassium EDTA tubes were tested for BNP by a fluorescence immunoassay. cTnT-hs was determined with an electrochemiluminescence sandwich test, which employs two specific monoclonal antibodies directed against cardiac troponin. The BNP cutoff is 100 pg/mL for patients aged 1 to 14 years, while that of cTnT-hs is 14 ng/L. All patients were monitored from hospitalization to discharge. Result(s): At least one of the two biomarkers resulted pathologic in 35 (66%) patients, while 18 (34%) were negative. The 35 pathologic cases were distributed as follows: 12 were simultaneously positive for cTnT-hs and BNP;13 were only positive for BNP, and 10 only positive for cTnT-hs. Sick children had a BNP mean value of 634 pg/mL at hospitalization, and of 94 pg/mL at discharge. For cTnT-hs, the initial mean value was 46 ng/l and the final was 17 ng/L. Twelve children with both altered values were monitored for a longer time, as they returned negative more slowly. Repeated dosages of the two analytes from hospitalization to discharge, showed a constant decrease over the time. After about ten days from the first dosage, both parameters returned to values near to the relative cutoffs. Conclusion(s): Measuring BNP and cTnt-hs can be useful for screening and monitoring pediatric patients positive for anti-SARSCoV-2 IgG.Copyright © 2022 EDIZIONI MINERVA MEDICA.
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Background. Pandemic caused by severe acute respiratory syndrome coronavirus 2 (COVID19) raises a smash barrier for clinicians and patients since 2 years. Limited information is available on disease course after COVID19 infection or vaccination in patients with idiopathic inflammatory myopathies (IIM). Objective(s): The primary goals of the current research were to assess frequency and outcome of COVID19 disease and to determine the vaccination rate and effect in our IIM cohort. Secondary objectives were to search for risk factors of infection, predictive factors of hospitalization and to assess incidence of pots-vaccination adverse events and breakthrough infections. Methods. We identified the confirmed COVID19 positive patients and assessed disease course and outcome on 01/06/2021 in our cohort then patients were prospectively followed. Incidence and complications of infection and vaccination were determined by questionnaires and using the database. Anti-SARS-CoV-2 spike protein electrochemiluminescent immunoassay has been used to assess seroconversion. Disease activity was determined by physician global activity. Results. A total of 176 patients were screened and 101 participated in the study. By 01/06/2021, the COVID infection rate was 34.7%, which was significantly higher than the national prevalence at that time (8.2%). A third of these infections occurred asymptomatically or mild, but 20% of the infected patients were hospitalized, one patient died. Longer disease duration (8.67 vs. 17.87 years;p=0.003) and higher incidence of anti-Jo-1 antibody (57% vs. 10%;p=0.018) were significantly associated with hospitalization. All patients became seropositive after COVID19 infection regardless of immunosuppressive therapy or symptoms severity, meanwhile 72.3% of patients became seropositive after vaccination. Different vaccines induced various titer of antibody against the spike protein. Significantly higher antibody titers was detected after Pfizer-BioNTech (177.1 U / ml vs. 81.1 U / ml;p=0.001) and numerically lower ones after AstraZeneca (45.05 U/ml vs. 126.93 U/ml p=0.054) vaccination compared to others. Patients receiving steroid therapy had significantly decreased post-vaccination antibody response compared to those without steroid treatment (94.03 U/ml vs. 165.6 U/ ml;p=0.008). We did not found short term vaccine related major adverse events. Long term data by 15/02/2022 revealed more infections (42.57%), where anti-Jo1 positivity still showed significant association with hospitalization (50% vs. 9%;p=0.0103). Breakthrough infection was detected in 9,25 % of the vaccinated patients, which was significantly more often after Astra Zeneca vaccination (40 % vs. 7%, p=0.017). All the fatal (n=3) COVID infections occurred in patients with seronegativity to anti-spike protein regardless vaccination. We identified 7,4 % post vaccination disease relapse needing therapy changes and 24,7% new autoantibody positivity. Conclusions. Based on our results, myositis may be associated with an increased risk of COVID19 disease. Independent risk factor for hospitalization for unvaccinated people is anti-Jo1 positivity. Anti-SARS-CoV2 vaccines are safe, tolerable, could prevent complicated infections and strongly recommended for IIM population. Further investigation is required to assess clinical significance of post-vaccination disease flare.
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Signal detection in a label-based immunoassay is performed normally when the antigen/antibody binding reaction reaches the equilibrium state during the incubation period of an assay process. Shortening the incubation period in an assay helps reduce the turnaround time and is particularly valuable for point-of-care testing, but the cost is the reduction of signal level and, possibly, measurement precision as well. This work demonstrates that the signal loss could be offset by the stronger emission of an electronically neutral ruthenium(II) complex label, Ru(2, 2′-bipyridine) (bathophenanthroline disulfonate)[4-(2, 2′-bipyridin-4-yl)butanoic acid], used in the electrochemiluminescence (ECL) immunoassay. Combined with the uniquely well-established flow-through washing process in the automated ECL analyzers and the precise control over liquid handling, the assays performed with a 5-minute incubation period showed the same signal level and measurement precision as those of conventional ECL assays. Additionally, the absence of biotin and streptavidin components in the reagent formulation avoids the biotin-streptavidin interaction during assay incubation and fundamentally eliminates the interference of biotin, especially when used in some high-dose therapies. The results obtained from the procalcitonin prototype kit and the supporting evidence from other preliminary reagents (for SARS-CoV-2 N protein and troponin T) are general. The nonequilibrium detection, along with the downsized instrument design, makes the enhanced ECL (EECL) technology a fast high-performance POCT platform that provides the same high-quality data as those generated from the widely deployed [Ru(bpy)3]2+ based laboratorial ECL systems. The anticipated regulatory approval and follow-up clinical implementation will be a significant stride in the decade-long pursuit of novel ECL labels. © 2023 The Author(s)
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SARS-CoV-2-specific IgM antibodies wane during the first three months after infection and IgG antibody levels decline. This may limit the ability of antibody tests to identify previous SARS-CoV-2 infection at later time points. To examine if the diagnostic sensitivity of antibody tests falls off, we compared the sensitivity of two nucleoprotein-based antibody tests, the Roche Elecsis II Anti-SARS-CoV-2 and the Abbott SARS-CoV-2 IgG assay and three glycoprotein-based tests, the Abbott SARS-CoV-2 IgG II Quant, Siemens Atellica IM COV2T and Euroimmun SARS-CoV-2 assay with 53 sera obtained 6 months after SARS-CoV-2 infection. The sensitivity of the Roche, Abbott SARS-CoV-2 IgG II Quant and Siemens antibody assays was 94.3% (95% confidence interval (CI) 84.3-98.8%), 98.1 % (95% CI: 89.9-100%) and 100 % (95% CI: 93.3-100%). The sensitivity of the N-based Abbott SARS-CoV-2 IgG and the glycoprotein-based Euroimmun ELISA was 45.3 % (95% CI: 31.6-59.6%) and 83.3% (95% CI: 70.2-91.9%). The nucleoprotein-based Roche and the glycoprotein-based Abbott receptor binding domain (RBD) and Siemens tests were more sensitive than the N-based Abbott and the Euroimmun antibody tests (p = 0.0001 to p = 0.039). The N-based Abbott antibody test was less sensitive 6 months than 4-10 weeks after SARS-CoV-2 infection (p = 0.0001). The findings show that most SARS-CoV-2 antibody assays correctly identified previous infection 6 months after infection. The sensitivity of pan-Ig antibody tests was not reduced at 6 months when IgM antibodies have usually disappeared. However, one of the nucleoprotein-based antibody tests significantly lost diagnostic sensitivity over time.
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A new and reliable method has been constructed for detecting severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) open reading frames 1ab (ORF1ab) gene via highly sensitive electrochemiluminescence (ECL) biosensor technology based on highly efficient asymmetric polymerase chain reaction (asymmetric PCR) amplification strategy. This method uses magnetic particles coupled with biotin-labeled one complementary nucleic acid sequence of the SARS-CoV-2 ORF1ab gene as the magnetic capture probes, and [Formula: see text]-labeled amino-modified another complementary nucleic acid sequence as the luminescent probes, and then a detection model of magnetic capture probes-asymmetric PCR amplification nucleic acid products-[Formula: see text]-labeled luminescent probes is formed, which combines the advantages of highly efficient asymmetric PCR amplification strategy and highly sensitive ECL biosensor technology, enhancing the method sensitivity of detecting the SARS-CoV-2 ORF1ab gene. The method enables the rapid and sensitive detection of the ORF1ab gene and has a linear range of 1-[Formula: see text] copies/[Formula: see text], a regression equation of [Formula: see text] = [Formula: see text] + 2919.301 ([Formula: see text] = 0.9983, [Formula: see text] = 7), and a limit of detection (LOD) of 1 copy/[Formula: see text]. In summary, it can meet the analytical requirements for simulated saliva and urine samples and has the benefits of easy operation, reasonable reproducibility, high sensitivity, and anti-interference abilities, which can provide a reference for developing efficient field detection methods for SARS-CoV-2.
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Introduction: IL-6 is the key molecule of cytokine storm in COVID-19. Dyslipidemia is a common complication in patients with Coronavirus disease 2019 (COVID-19), but the association of dyslipidemia with the severity of COVID-19 is still unclear. In this study, we aimed to investigate the biochemical alterations of High-Density Lipoprotein Cholesterol (HDL-C), and Interleukin-6 (IL-6) in COVID-19 patients and their relationships with the disease severity. Material(s) and Method(s): We conducted a retrospective single-institutional study of 99 consecutive confirmed cases of COVID-19. Serum IL-6 and HDL-C concentrations, demographic and clinical profile were collected during hospital stay. Duration of study was from September 2020 to August 2021. Descriptive statistics were applied to summarize the demographic data. Results are reported as mean with standard deviation. Receiver operating characteristic curve (ROC) analysis was used to compare biochemical markers. Result(s): Serum HDL-C levels had a significant positive correlation with SpO2 with correlation coefficient r = 0.589. Serum IL-6 had a negative correlation with SpO2 with correlation coefficient r =-0.632. The AUC for IL6 and HDL-C in predicting COVID severity is 0.982 and 0.985 respectively. Conclusion(s): HDL-C is decreased and IL-6 is increased with the disease severity.Copyright © 2023, Dr Yashwant Research Labs Pvt Ltd. All rights reserved.
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Objective: To find the trend of seropositivity of antiSARS-CoV-2 antibodies in registered patients for COVID-19 in Dow Diagnostic Reference and Research laboratory Methodology: A total of 5247 patients were enrolled for SARS CoV2 antibodies analysis from 01 August to 31 December, 2020. Patient consent was attained and questionnaire forms were filled. Samples were tested for anti-SARS-CoV-2 antibodies on (Roche Cobase 601). Result(s): In 5247 patient's samples, seropositivity of SARS CoV2 was found in 2425 (46.2%) samples. Seroprevalence in males was 28.4% (n;1491) as compared to females, who showed 17% (n;934). The age group G3 (> 46 to 60 years) showed higher seropositivity (n = 604/1118, 54%) as related to other age groups. Out of total reactive patients, only 30% (n;727) reported recent symptoms while 70% (n;1697) were asymptomatic. Fever was observed to be the most common symptom followed by dry cough. The most commonly affected areas were East 2353 (44%), South 855 (16.01%), Malir 793 (14.85%), Center zone 589 (11.03%) and Korangi area 378 (7.08%). The frequency of seropositivity showed an increasing pattern in the six months from August 2020 to December 2020. It was found to be 11.5% in August, 13.6% in September, 13.9% in October, and 42.5% in December 2020. Conclusion(s): The trend of seropositivity revealed a gradual upward course in the duration of study period. Nearly, two thirds of the patients were asymptomatic indicating the fact that many individuals were silently exposed to the infection and developed antibodies through their natural defense mechanism.Copyright © 2023, Pakistan Medical Association. All rights reserved.
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Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus. Following infection, antibodies are formed against the spike (S) and nucleocapsid (N) proteins, which are the primary viral antigens of SARS-CoV-2. This study aims to determine the antibody response three weeks post-infection and its persistence. To study antibody responses in COVID-19-positive individuals and to compare the degree of antibody response in symptomatic and asymptomatic individuals. The persistence of the antibody response was also assessed. Adult patients (> 15 years of age) who were diagnosed as COVID-19-positive by RT-PCR, three weeks after swab positivity were tested for total antibody levels against COVID-19 antigens by electrochemiluminescence assay. Out of 226 individuals, 129 were symptomatic and 97 were asymptomatic. Among the 129 symptomatic individuals, 74 exhibited an antibody response, whereas in the asymptomatic individuals, only 10 exhibited an antibody response. The antibody response was found to be significant in symptomatic individuals compared to that in asymptomatic individuals (p < 0.05). All follow-up individuals were seropositive at the end of both 6 and 8 months. Antibodies against SARS-CoV-2 persist for 8 months following infection. Despite the waning of antibodies against the nucleocapsid antigen, there was no complete disappearance of antibodies.Copyright © 2023 The Author(s).
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At the end of 2019, the novel coronavirus disease 2019 (COVID-19), a cluster of atypical pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been known as a highly contagious disease. Herein, we report the MXene/P-BiOCl/Ru(bpy)32+ heterojunction composite to construct an electrochemiluminescence (ECL) immunosensor for SARS-CoV-2 nucleocapsid protein (CoVNP) determination. Two-dimensional (2D) material ultrathin phosphorus-doped bismuth oxychloride (P-BiOCl) is exploited and first applied in ECL. 2D architectures MXene not only act as "soft substrate" to improve the properties of P-BiOCl, but also synergistically work with P-BiOCl. Owing to the inimitable set of bulk and interfacial properties, intrinsic high electrochemical conductivity, hydrophilicity and good biocompatible of 2D/2D MXene/P-BiOCl/Ru(bpy)32+, this as-exploited heterojunction composite is an efficient signal amplifier and co-reaction accelerator in the presence of tri-n-propylamine (TPA) as a coreactant. The proposed MXene/P-BiOCl/Ru(bpy)32+-TPA system exhibits a high and stable ECL signal and achieves ECL emission quenching for "signal on-off" recognition of CoVNP. Fascinatingly, the constructed ECL biosensor towards CoVNP allows a wide linear concentration range from 1 fg/mL to 10 ng/mL and a low limit of detection (LOD) of 0.49 fg/mL (S/N = 3). Furthermore, this presented strategy sheds light on designing a highly efficient ECL nanostructure through the combination of 2D MXene architectures with 2D semiconductor materials in the field of nanomedicine. This ECL biosensor can successfully detect CoVNP in human serum, which can promote the prosperity and development of diagnostic methods of SARS-CoV-2.
Subject(s)
Biosensing Techniques , COVID-19 , Humans , Biosensing Techniques/methods , Bismuth , COVID-19/diagnosis , Electrochemical Techniques/methods , Immunoassay/methods , Luminescent Measurements/methods , Nucleocapsid Proteins , SARS-CoV-2ABSTRACT
Polymers have attracted attention as luminophores due to their excellent electrochemiluminescence (ECL) properties. However, the current research and application of polymers mainly focus on anode emission, and ECL efficiency is not high enough, thus showing a limited application. This work exploited the persulfate-mediated dual-emission characteristics of poly[2,5-dioctyl-1,4-phenylene] polymer nanoparticles (PDP PNPs). The two ECL emissions were collected synchronously at -2.0V and +1.0V with persulfate (S2O82-) as cathodic coreactant and 3-(dibutylamino) propylamine (TDBA) as anodic coreactant, respectively. Interestingly, S2O82- can simultaneously mediate the double emissions, significantly enhancing both cathode emission and anode emission. The dual-emission mechanism was explored carefully and enhancement mechanism of cathodic coreactant S2O82- to anodic emission was hypothesized to be attributed to SO4∙− radicals, which was produced from S2O82- during cathodic potential scanning and oxidized PDP PNPs to generate more cation radical, thus enhancing anodic emission of PDP PNPs. Moreover, the black hole quencher-2 (BHQ2) was exploited as dual-function moderator to quench dual emissions of PDP PNPs synchronously. PDP PNPs coupled with BHQ2 to build ECL ratiometric system for detecting SARS-CoV-2 RdRp gene and its limit of detection was 25.1 aM. Persulfate-mediated double emissions provided a new way to improve the efficiency of ECL emission from polymers and expand their application. The clever integration of dual-emitting PDP PNPs and dual-regulating BHQ2 created a promising single-luminophore-based ratiometric ECL platform, developed an attractive ECL method for detecting SARS-CoV-2 RdRp gene.
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The vaccination efficacy can indirectly be assessed through the quantification of neutralizing antibodies. Very few data are available on Covishield efficacy in terms of neutralizing antibody expression upon vaccination. This study is focused on profiling of neutralizing antibody expression during and after the Covishield two shot vaccination and observing COVID-19 infection in vaccinated participants during the period. SARS CoV-2 neutralizing antibody concentrations in samples were estimated using electrochemiluminescence immunoassay kit for Lifotronics eCL8000. The sampling had been done sequentially at 45th, 85th day after 1st dose and 15th day after 2nd dose Covishield vaccination. Parallelly, in order to confirm the total SARS CoV-2 IgG response in COVID-19 infection, measured the IgG using SARS CoV-2 IgG lateral flow immunoassay test kit. The subjects previously infected with COVID-19 before 1st dose vaccination demonstrated high neutralizing antibody (> 10AU/ml). In COVID-19 uninfected subjects, there was a sudden incline in neutralizing antibody after the 2nd dose. Infection with SARS CoV-2 between 1st and 2nd dose of Covishield vaccination implicate that the level of neutralizing antibody in serum after 1st dose was not adequate to combat the virus and prevent infection. We observed COVID-19 infection in participants even after 2nd dose of vaccination. Interestingly, there was no protection against SARS CoV-2 even with a high neutralizing antibody expression of 188.5 AU/mL after the 2nd dose. Findings of Covishield efficacy in different cohort samples before and after 2 doses of Covishield vaccination provide impetus for improvement or development of next generation vaccines.
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Background. Which components of the immune response to SARS-CoV-2 vaccination best protect against subsequent infection remains unclear. We explored SARS-CoV-2 specific antibody and B-cell responses post 3rd dose vaccine and their relationship to subsequent SARS-CoV-2 infection. Methods. In a multicentre prospective cohort, adult subjects provided samples before and 14 days (d14) post 3rd dose vaccine with Pfizer-BioNTech 162b2. At 18-22 weeks post vaccine, subjects self-reported SARS-CoV-2 infection (confirmed by PCR or antigen test). We used electrochemiluminescence assays to quantify antibodies to SARS-CoV-2 spike subunit 1 (S1), subunit 2 (S2) and receptor-binding domain (RBD) in plasma (reported inWHOIU/mL). In a subset of subjects, we assessed SARS-CoV-2 specific differentiated B-cell (plasma cell) and memory B-cell responses from peripheral blood mononuclear cells. Unstimulated plasma cells, and memory B cells stimulated with R848 and IL2, were seeded on plates coated with RBD or full Spike antigen and antigen-specific responses measured by ELISpot (Mabtech ELISpot, Sweden). We compared between group differences by Wilcoxon signed rank or Mann-Whitney tests. Data are median [IQR] unless specified. Results. Of 133 subjects (age 43 [32-50], 81.2% female (table 1), 77 subjects in the B-cell subgroup (table 2)), 47 (35.3%) reported SARS-CoV-2 infection post 3rd vaccine. Antibody titres, plasma cell and memory B-cell responses all increased significantly at d14 post 3rd vaccine (Table 1 & 2, all P< 0.001). Although d14 antibody titres did not differ in those with and without subsequent infection (table 1), those reporting subsequent infection had significantly lower d14 RBD-specific plasma cells and a lower proportion of RBD-specific memory B-cells (Figure 1a-b, both P< 0.05). Similar results were observed with full-spike-specific memory B-cell responses (Figure 1d). The differences persisted when the non-infected group was restricted only to those reporting a confirmed close contact (n=26). Conclusion. Infection following 3rd dose vaccine is associated with lower d14 circulating and memory B cell responses, but not antibody titres, suggesting B-cell responses better predict protection against subsequent SARS-CoV-2 infection.
ABSTRACT
Background. We studied immunological response against SARS-CoV-2 after two doses of vaccine in health care workers (HCW) at our Infectious Disease Unit Methods. We enrolled prospectively HCW without (group A) and with previous infection (group B). We collected peripheral blood at baseline (before the BNT162b2 vaccine), T1 (before the 2nd dose), T2 and T6 (after 1 and 6 months after of 2nd dose). The activation induced cell marker assay (AIM) was performed with CD4 and CD8 Spike peptide megapools (MPs). We evaluated the Stimulation Index (SI) as AIM+ stimulated cells/negative control (positive response SI >= 2). Quantitative antibodies (Abs) to Spike-1 protein (S) and to nucleocapside protein (N) were detected with an electrochemiluminescence immunoassay. We tested at T6 the responses to alpha, beta, gamma, delta and epsilon variants MPs.We used the linear mixed model with random intercept adjusted for age and sex to compare specific times to T0. To assess differences over time between groups the interaction with time was tested. Results. In group A 13/22 (59%) were female vs 5/7 (71%) group B, the mean age 40 vs 38 years, respectively. For CD4+ Spike the overall rate of change over time was significant at T1 (p=0.038) and at T2 (p< 0.001) vs T0 with a decreasing at T6 (p not significant) [Figure 1] with a trend of higher response in group A. In group B the CD8 + Spike reactivity increased at T1(p=0.037) and at T6 (p=0.005) vs T0. The interaction between SI and time was statistically significant at T1 (p=0.033);T2 (p= 0.046) and T6 (p=0.035) (mean values in group B higher than A). For overall population, the anti-S Abs significantly increased at T1 vs T0, T2 vs T0 and at T6 vs T0 [Figure 2A]. The group B at T6 retained a higher anti S response but the rate of change significantly differs between the two group (overall interaction: p< 0.001) [Figure 2B]. At T6 in both groups we found a high CD4+ T cells response to epsilon variant, even if not detected as circulant virus. Conclusion. The humoral response was persistent and increased in previous infected subjects. The CD4+T cells response after vaccination retained a response in uninfected subject, with an increasing trend and with a response to non-circulating variants. The vaccine could help the CD8+ T cells reactivity specific for Spike peptides.
ABSTRACT
Background. A wide array of assays to detect the serologic response to SARS-CoV-2 have been developed since the emergence of the pandemic. The majority of these are either qualitative or semi-quantitative, detect antibodies against one antigenic target, and are not adaptable to new antigens. Methods. We developed a new, multiplex immunoassay to detect antibodies against the receptor binding domain, S1 and S2 spike subunits and nucleocapsid (N) antigens of SARS-CoV-2 (the CEPHR SARS-CoV-2 Serology Assay). This assay uses electrochemiluminescence technology which allows for a broad dynamic range, and a linker format which allows for the addition of new antigenic targets. We tested this assay on a series of biobanked samples and validated its performance against the Abbott SARS-CoV-2 IgG and Abbott SARS-CoV-2 IgG II assays, and the MesoScale Diagnostics V-PLEX SARS-CoV-2 Panel 2 Kit. Results. Participant demographics are shown in Table 1. The mean (standard deviation (SD)) intra-assay (within plate) coefficient of variation (CV) of 80 plasma samples run on the same plate was 3.9% (2.9) for N, 3.8% (6.2) for RBD, 3.8% (5.9) for S1 and 3.9% (5.3) for S2. The mean (SD) inter-assay CV derived from 5 samples run across 3 days by two different operators was 11% (6.5) for N, 13% (5.7) for RBD, 14% (8.9) for S1 and 13% (5.1) for S2. In the convalescent group (n=193), overall sensitivity for each assay was;RBD 82% (95% CI 76-87), S1 86% (81-91%), S2 88% (83 - 92%) and N 72% (64 - 78%). Sensitivity improved when analysis included only individuals who were sampled more than 14 days from onset of symptoms (n=166), RBD 87% (81 - 95%), S1 91% (85 - 95%), S2 91% (85 - 95%) but not for the N-target (73% (66-80%)). In vaccinated individuals (n = 58), 100% (94-100%) had both detectable RBD and S1 antibodies. Overall specificity was 96% (87-99%) for RBD, 90% (78-97%) for S1, 94% (84-99%) for S2 and 90% (78-97%) for N. There was excellent correlation between the Abbott IgG II and both CEPHR anti-RBD IgG (rho 0.91) and CEPHR anti-S1 IgG (rho 0.9, both p < 0.001, Figure 1.) and the V-PLEX full spike and both CEPHR RBD IgG (rho 0.83) and S1 IgG (rho 0.82, both p < 0.001, Figure 4). Conclusion. The CEPHR SARS-CoV-2 Serology Assay is a robust, customisable, multiplex serologic assay for the detection of several different IgG specific to SARS-CoV-2.