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1.
Clin Infect Dis ; 2022 Sep 02.
Article in English | MEDLINE | ID: covidwho-2017871

ABSTRACT

The diagnosis of post-acute sequelae of COVID-19 (PASC) poses an ongoing medical challenge. To identify biomarkers associated with PASC we analyzed plasma samples collected from PASC and COVID-19 patients to quantify viral antigens and inflammatory markers. We detect SARS-CoV-2 spike predominantly in PASC patients up to 12 months post-diagnosis.

2.
Clin Infect Dis ; 2021 Nov 02.
Article in English | MEDLINE | ID: covidwho-2008524

ABSTRACT

The SARS-CoV-2 mRNA vaccine-induced humoral response and reactogenicity profile are described in allogeneic hematopoietic stem cell transplant (HSCT) recipients. 75.0% (by Simoa assay) or 80.0% (by Roche assay) of the HSCT cohort had a positive antibody response upon series completion, as compared to 100% in the healthy cohort.

3.
Open forum infectious diseases ; 2022.
Article in English | EuropePMC | ID: covidwho-1999431

ABSTRACT

Background Patients with lymphoid malignancies are at risk for poor COVID-19 related outcomes and have reduced vaccine-induced immune responses. Currently a three-dose primary regimen of mRNA vaccines is recommended in the U.S. for immunocompromised hosts. Methods A prospective cohort study of healthy adults (n = 27) and patients with lymphoid malignancies (n = 94) was conducted, with longitudinal follow-up through completion of a two or three-dose primary mRNA COVID vaccine series, respectively. Humoral responses were assessed in all participants, and cellular immunity in a subset of participants. Results The rate of seroconversion (68.1% v. 100%) and the magnitude of peak anti-S IgG titer (median anti-S IgG 32.4, IQR 0.48-75.0 v. 72.6, IQR 51.1-100.1;p = 0.0202) were both significantly lower in patients with lymphoid malignancies as compared to the healthy cohort. However, peak titers of patients with lymphoid malignancies who responded to vaccination were similar to healthy cohort titers (median anti-S IgG 64.3, IQR 23.7 - 161.5, p = 0.7424). The third dose seroconverted 7/41 (17.1%) patients who were seronegative after the first two doses. Although most patients with lymphoid malignancies produced vaccine-induced T-cell responses in the subset studied, B-cell frequencies were low with minimal memory cell formation. Conclusions A three-dose primary mRNA series enhanced anti-S IgG responses to titers equivalent to healthy adults in patients with lymphoid malignancies who were seropositive after the first two doses and seroconverted 17.1% who were seronegative after the first two doses. T-cell responses were present, raising the possibility that the vaccines may confer some cell-based protection even if not measurable by anti-S IgG.

4.
Am J Trop Med Hyg ; 107(4): 845-849, 2022 10 12.
Article in English | MEDLINE | ID: covidwho-1994318

ABSTRACT

Early detection of SARS-CoV-2 infection is crucial to prevent its spread. This study aimed to document test sensitivity/specificity, correlation with cycle threshold value from polymerase chain reaction (PCR), fitness-for-use in different populations and settings, and user perspectives that could inform large-scale implementation. In this study, we evaluated the performance of a rapid antigen detection test, BD Veritor, and compared this (and another rapid test, Standard Q) against reverse transcription PCR (RT-PCR) in terms of sensitivity and specificity in 130 symptomatic and 130 asymptomatic adults. In addition, we evaluated the suitability and ease of use of the BD Veritor test in a subsample of study participants (n = 42) and implementers (n = 5). At 95% confidence interval, the sensitivity of the BD Veritor and Standard Q test were 70% and 63% in symptomatic and 87% and 73% in asymptomatic individuals, respectively, regarding positive SARS-CoV-2 RT-PCR results. Overall, the BD Veritor test was 78% sensitive and 99.5% specific compared with RT-PCR irrespective of the cycle threshold. This warrants large field evaluation as well as use of the rapid antigen test for quick assessment of SARS-CoV-2 for containment of epidemics in the country.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antigens, Viral , Bangladesh/epidemiology , COVID-19/diagnosis , COVID-19 Testing , Humans , Sensitivity and Specificity
5.
Nat Biomed Eng ; 6(8): 968-978, 2022 08.
Article in English | MEDLINE | ID: covidwho-1984391

ABSTRACT

Rapid, accurate and frequent detection of the RNA of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) and of serological host antibodies to the virus would facilitate the determination of the immune status of individuals who have Coronavirus disease 2019 (COVID-19), were previously infected by the virus, or were vaccinated against the disease. Here we describe the development and application of a 3D-printed lab-on-a-chip that concurrently detects, via multiplexed electrochemical outputs and within 2 h, SARS-CoV-2 RNA in saliva as well as anti-SARS-CoV-2 immunoglobulins in saliva spiked with blood plasma. The device automatedly extracts, concentrates and amplifies SARS-CoV-2 RNA from unprocessed saliva, and integrates the Cas12a-based enzymatic detection of SARS-CoV-2 RNA via isothermal nucleic acid amplification with a sandwich-based enzyme-linked immunosorbent assay on electrodes functionalized with the Spike S1, nucleocapsid and receptor-binding-domain antigens of SARS-CoV-2. Inexpensive microfluidic electrochemical sensors for performing multiplexed diagnostics at the point of care may facilitate the widespread monitoring of COVID-19 infection and immunity.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/diagnosis , Humans , Lab-On-A-Chip Devices , Plasma , RNA, Viral , Saliva , Spike Glycoprotein, Coronavirus
6.
Front Microbiol ; 13: 910156, 2022.
Article in English | MEDLINE | ID: covidwho-1928435

ABSTRACT

During the first few months of the global Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic, the medical research community had to expeditiously develop, select, and deploy novel diagnostic methods and tools to address the numerous testing challenges presented by the novel virus. Integrating a systematic approach to diagnostic selection with a rapid validation protocol in a clinical setting can shorten the timeline to bring new technologies to practice. In response to the urgent need to provide tools for identifying SARS-CoV-2-positive individuals, we developed a framework for assessing technologies against a set of prioritized performance metrics to guide device selection. We also developed and proposed clinical validation frameworks for the rapid screening of new technologies. The rubric described here represents a versatile approach that can be extended to future technology assessments and can be implemented in preparation for future emerging pathogens.

7.
Front Microbiol ; 13: 893801, 2022.
Article in English | MEDLINE | ID: covidwho-1903084

ABSTRACT

Background: There is an urgent need for harmonization between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology platforms and assays prior to defining appropriate correlates of protection and as well inform the development of new rapid diagnostic tests that can be used for serosurveillance as new variants of concern (VOC) emerge. We compared multiple SARS-CoV-2 serology reference materials to the WHO International Standard (WHO IS) to determine their utility as secondary standards, using an international network of laboratories with high-throughput quantitative serology assays. This enabled the comparison of quantitative results between multiple serology platforms. Methods: Between April and December 2020, 13 well-characterized and validated SARS-CoV-2 serology reference materials were recruited from six different providers to qualify as secondary standards to the WHO IS. All the samples were tested in parallel with the National Institute for Biological Standards and Control (NIBSC) 20/136 and parallel-line assays were used to calculate the relevant potency and binding antibody units. Results: All the samples saw varying levels of concordance between diagnostic methods at specific antigen-antibody combinations. Seven of the 12 candidate materials had high concordance for the spike-immunoglobulin G (IgG) analyte [percent coefficient of variation (%CV) between 5 and 44%]. Conclusion: Despite some concordance between laboratories, qualification of secondary materials to the WHO IS using arbitrary international units or binding antibody units per milliliter (BAU/ml) does not provide any benefit to the reference materials overall, due to the lack of consistent agreeable international unit (IU) or BAU/ml conversions between laboratories. Secondary standards should be qualified to well-characterized reference materials, such as the WHO IS, using serology assays that are similar to the ones used for the original characterization of the WHO IS.

8.
Clin Infect Dis ; 74(4): 715-718, 2022 03 01.
Article in English | MEDLINE | ID: covidwho-1702854

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins were measured in longitudinal plasma samples collected from 13 participants who received two doses of mRNA-1273 vaccine. Eleven of 13 participants showed detectable levels of SARS-CoV-2 protein as early as day 1 after first vaccine injection. Clearance of detectable SARS-CoV-2 protein correlated with production of immunoglobulin G (IgG) and immunoglobulin A (IgA).


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Immunoglobulin A , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/blood , Spike Glycoprotein, Coronavirus/genetics
9.
Critical care explorations ; 10(2), 2022.
Article in English | EuropePMC | ID: covidwho-1695117

ABSTRACT

OBJECTIVES: A recent study suggests that Multisystem Inflammatory Syndrome in Children (MIS-C) is triggered by gastrointestinal breach of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral particles from the gut lumen into systemic circulation. The virus remains in the gut weeks to months after respiratory infection, causing zonulin release from the intestinal epithelial cells. Zonulin loosens tight junctions, permitting trafficking of highly inflammatory viral particles into circulation. Current MIS-C treatments target the subsequent immune hyperactivation, not the causative loss of mucosal barrier integrity. Larazotide, a zonulin inhibitor, prevents breakdown of tight junctions, limiting antigen trafficking. DESIGN: Children with MIS-C were treated with larazotide as an adjuvant to steroid/intravenous immunoglobulin therapy. Clinical outcomes, SARS-CoV-2 antigenemia, and cytokine profiles are reported. Outcomes were compared with children with MIS-C receiving steroids and/or IVIG therapy alone. PATIENTS: Four children with MIS-C, ages 3–17 years, were enrolled. INTERVENTIONS: Patients were treated with open label larazotide 10 mcg/kg (maximum 500 mcg/dose) orally four times daily for 21 days. MEASUREMENTS AND MAIN RESULTS: All four patients tolerated larazotide without adverse effects and displayed reduction in Spike antigenemia to undetectable levels. When compared with 22 children with MIS-C receiving steroids and/or intravenous immunoglobulin therapy alone, larazotide-treated patients reported significantly improved time to resolution of gastrointestinal symptoms (p = 0.03), and time to clearance of Spike antigenemia (p = 0.04), plus a trend towards shorter length of stay. CONCLUSIONS: Larazotide appears safe and well-tolerated and may offer potential benefit as an adjuvant to immune-targeted therapies. Expansion of clinical trials is urgently needed to ascertain the clinical impact of larazotide on MIS-C.

10.
Clin Lab Med ; 42(1): 97-109, 2022 03.
Article in English | MEDLINE | ID: covidwho-1654209

ABSTRACT

Humoral immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during acute infection and convalescence has been widely studied since March 2020. In this review, the authors summarize literature on humoral responses to SARS-CoV-2 antigens with a focus on spike, nucleocapsid, and the receptor-binding domain as targets of antibody responses. They highlight serologic studies during acute SARS-CoV-2 infection and discuss the clinical relevance of antibody levels in COVID-19 progression. Antibody responses in pediatric COVID-19 patients are also reviewed. Finally, the authors discuss antibody responses during convalescence and their role in protection from SARS-CoV-2 reinfection.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Antibody Formation , Child , Humans , Immunity, Humoral
11.
Med (N Y) ; 2(9): 1050-1071.e7, 2021 09 10.
Article in English | MEDLINE | ID: covidwho-1482809

ABSTRACT

BACKGROUND: T cells control viral infection, promote vaccine durability, and in coronavirus disease 2019 (COVID-19) associate with mild disease. We investigated whether prior measles-mumps-rubella (MMR) or tetanus-diphtheria-pertussis (Tdap) vaccination elicits cross-reactive T cells that mitigate COVID-19. METHODS: Antigen-presenting cells (APC) loaded ex vivo with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), MMR, or Tdap antigens and autologous T cells from COVID-19-convalescent participants, uninfected individuals, and COVID-19 mRNA-vaccinated donors were co-cultured. T cell activation and phenotype were detected by interferon-γ (IFN-γ) enzyme-linked immunospot (ELISpot) assays and flow cytometry. ELISAs (enzyme-linked immunosorbant assays) and validation studies identified the APC-derived cytokine(s) driving T cell activation. TCR clonotyping and single-cell RNA sequencing (scRNA-seq) identified cross-reactive T cells and their transcriptional profile. A propensity-weighted analysis of COVID-19 patients estimated the effects of MMR and Tdap vaccination on COVID-19 outcomes. FINDINGS: High correlation was observed between T cell responses to SARS-CoV-2 (spike-S1 and nucleocapsid) and MMR and Tdap proteins in COVID-19-convalescent and -vaccinated individuals. The overlapping T cell population contained an effector memory T cell subset (effector memory re-expressing CD45RA on T cells [TEMRA]) implicated in protective, anti-viral immunity, and their detection required APC-derived IL-15, known to sensitize T cells to activation. Cross-reactive TCR repertoires detected in antigen-experienced T cells recognizing SARS-CoV-2, MMR, and Tdap epitopes had TEMRA features. Indices of disease severity were reduced in MMR- or Tdap-vaccinated individuals by 32%-38% and 20%-23%, respectively, among COVID-19 patients. CONCLUSIONS: Tdap and MMR memory T cells reactivated by SARS-CoV-2 may provide protection against severe COVID-19. FUNDING: This study was supported by a National Institutes of Health (R01HL065095, R01AI152522, R01NS097719) donation from Barbara and Amos Hostetter and the Chleck Foundation.


Subject(s)
COVID-19 , Measles , Whooping Cough , COVID-19/prevention & control , Humans , Mumps Vaccine , Receptors, Antigen, T-Cell , Rubella Vaccine , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , T-Lymphocytes
12.
Adv Healthc Mater ; 10(22): e2101370, 2021 11.
Article in English | MEDLINE | ID: covidwho-1449905

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic demonstrates the importance of generating safe and efficacious vaccines that can be rapidly deployed against emerging pathogens. Subunit vaccines are considered among the safest, but proteins used in these typically lack strong immunogenicity, leading to poor immune responses. Here, a biomaterial COVID-19 vaccine based on a mesoporous silica rods (MSRs) platform is described. MSRs loaded with granulocyte-macrophage colony-stimulating factor (GM-CSF), the toll-like receptor 4 (TLR-4) agonist monophosphoryl lipid A (MPLA), and SARS-CoV-2 viral protein antigens slowly release their cargo and form subcutaneous scaffolds that locally recruit and activate antigen-presenting cells (APCs) for the generation of adaptive immunity. MSR-based vaccines generate robust and durable cellular and humoral responses against SARS-CoV-2 antigens, including the poorly immunogenic receptor binding domain (RBD) of the spike (S) protein. Persistent antibodies over the course of 8 months are found in all vaccine configurations tested and robust in vitro viral neutralization is observed both in a prime-boost and a single-dose regimen. These vaccines can be fully formulated ahead of time or stored lyophilized and reconstituted with an antigen mixture moments before injection, which can facilitate its rapid deployment against emerging SARS-CoV-2 variants or new pathogens. Together, the data show a promising COVID-19 vaccine candidate and a generally adaptable vaccine platform against infectious pathogens.


Subject(s)
COVID-19 , SARS-CoV-2 , Adaptive Immunity , Antibodies, Viral , Biocompatible Materials , COVID-19 Vaccines , Humans
13.
Angew Chem Int Ed Engl ; 60(49): 25966-25972, 2021 12 01.
Article in English | MEDLINE | ID: covidwho-1427057

ABSTRACT

Coronavirus disease 2019 (COVID-19) manifests with high clinical variability and warrants sensitive and specific assays to analyze immune responses in infected and vaccinated individuals. Using Single Molecule Arrays (Simoa), we developed an assay to assess antibody neutralization with high sensitivity and multiplexing capabilities based on antibody-mediated blockage of the ACE2-spike interaction. The assay does not require live viruses or cells and can be performed in a biosafety level 2 laboratory within two hours. We used this assay to assess neutralization and antibody levels in patients who died of COVID-19 and patients hospitalized for a short period of time and show that neutralization and antibody levels increase over time. We also adapted the assay for SARS-CoV-2 variants and measured neutralization capacity in pre-pandemic healthy, COVID-19 infected, and vaccinated individuals. This assay is highly adaptable for clinical applications, such as vaccine development and epidemiological studies.


Subject(s)
Antibodies, Neutralizing/immunology , COVID-19/immunology , Neutralization Tests/methods , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/immunology , Antigen-Antibody Reactions , COVID-19/pathology , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Case-Control Studies , Enzyme-Linked Immunosorbent Assay , Humans , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
15.
J Clin Invest ; 131(14)2021 07 15.
Article in English | MEDLINE | ID: covidwho-1311202

ABSTRACT

BACKGROUNDWeeks after SARS-CoV-2 infection or exposure, some children develop a severe, life-threatening illness called multisystem inflammatory syndrome in children (MIS-C). Gastrointestinal (GI) symptoms are common in patients with MIS-C, and a severe hyperinflammatory response ensues with potential for cardiac complications. The cause of MIS-C has not been identified to date.METHODSHere, we analyzed biospecimens from 100 children: 19 with MIS-C, 26 with acute COVID-19, and 55 controls. Stools were assessed for SARS-CoV-2 by reverse transcription PCR (RT-PCR), and plasma was examined for markers of breakdown of mucosal barrier integrity, including zonulin. Ultrasensitive antigen detection was used to probe for SARS-CoV-2 antigenemia in plasma, and immune responses were characterized. As a proof of concept, we treated a patient with MIS-C with larazotide, a zonulin antagonist, and monitored the effect on antigenemia and the patient's clinical response.RESULTSWe showed that in children with MIS-C, a prolonged presence of SARS-CoV-2 in the GI tract led to the release of zonulin, a biomarker of intestinal permeability, with subsequent trafficking of SARS-CoV-2 antigens into the bloodstream, leading to hyperinflammation. The patient with MIS-C treated with larazotide had a coinciding decrease in plasma SARS-CoV-2 spike antigen levels and inflammatory markers and a resultant clinical improvement above that achieved with currently available treatments.CONCLUSIONThese mechanistic data on MIS-C pathogenesis provide insight into targets for diagnosing, treating, and preventing MIS-C, which are urgently needed for this increasingly common severe COVID-19-related disease in children.


Subject(s)
COVID-19/etiology , COVID-19/physiopathology , Haptoglobins/physiology , Intestinal Mucosa/physiopathology , Protein Precursors/physiology , SARS-CoV-2 , Systemic Inflammatory Response Syndrome/etiology , Systemic Inflammatory Response Syndrome/physiopathology , Adolescent , Antigens, Viral/blood , Biomarkers/blood , COVID-19/virology , Case-Control Studies , Child , Child, Preschool , Female , Haptoglobins/antagonists & inhibitors , Humans , Infant , Infant, Newborn , Intestinal Mucosa/drug effects , Intestinal Mucosa/virology , Male , Oligopeptides/pharmacology , Permeability/drug effects , Proof of Concept Study , Protein Precursors/antagonists & inhibitors , Protein Precursors/blood , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/blood , Spike Glycoprotein, Coronavirus/immunology , Systemic Inflammatory Response Syndrome/virology , Young Adult
16.
J Appl Lab Med ; 6(6): 1561-1570, 2021 11 01.
Article in English | MEDLINE | ID: covidwho-1291298

ABSTRACT

BACKGROUND: Serological testing provides a record of prior infection with SARS-CoV-2, but assay performance requires independent assessment. METHODS: We evaluated 3 commercial (Roche Diagnostics pan-IG, and Epitope Diagnostics IgM and IgG) and 2 non-commercial (Simoa and Ragon/MGH IgG) immunoassays against 1083 unique samples that included 251 PCR-positive and 832 prepandemic samples. RESULTS: The Roche assay registered the highest specificity 99.6% (3/832 false positives), the Ragon/MGH assay 99.5% (4/832), the primary Simoa assay model 99.0% (8/832), and the Epitope IgG and IgM 99.0% (8/830) and 99.5% (4/830), respectively. Overall sensitivities for the Simoa, Roche pan-IG, Epitope IgG, Ragon/MGH IgG, and Epitope IgM were 92.0%, 82.9%, 82.5%, 64.5% and 47.0%, respectively. The Simoa immunoassay demonstrated the highest sensitivity among samples stratified by days postsymptom onset (PSO), <8 days PSO (57.69%) 8-14 days PSO (93.51%), 15-21 days PSO (100%), and > 21 days PSO (95.18%). CONCLUSIONS: All assays demonstrated high to very high specificities while sensitivities were variable across assays.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19 Serological Testing , Humans , Immunoassay , Immunoglobulin G , Immunoglobulin M , Sensitivity and Specificity
17.
Anal Chem ; 93(13): 5365-5370, 2021 04 06.
Article in English | MEDLINE | ID: covidwho-1147379

ABSTRACT

Tests for COVID-19 generally measure SARS-CoV-2 viral RNA from nasal swabs or antibodies against the virus from blood. It has been shown, however, that both viral particles and antibodies against those particles are present in saliva, which is more accessible than both swabs and blood. We present methods for highly sensitive measurements of both viral RNA and antibodies from the same saliva sample. We developed an efficient saliva RNA extraction method and combined it with an ultrasensitive antibody test based on single molecule array (Simoa) technology. We apply our test to the saliva of patients who presented to the hospital with COVID-19 symptoms, some of whom tested positive with a conventional RT-qPCR nasopharyngeal swab test. We demonstrate that combining viral RNA detection by RT-qPCR with antibody detection by Simoa identifies more patients as infected than either method alone. Our results demonstrate the utility of combining viral RNA and antibody testing from saliva, a single easily accessible biofluid.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Testing/methods , COVID-19/diagnosis , RNA, Viral/analysis , SARS-CoV-2/genetics , Saliva/immunology , COVID-19/virology , Female , Humans , Limit of Detection , Male , Real-Time Polymerase Chain Reaction , Reproducibility of Results , SARS-CoV-2/immunology
18.
medRxiv ; 2020 May 02.
Article in English | MEDLINE | ID: covidwho-900732

ABSTRACT

The COVID-19 pandemic continues to infect millions of people worldwide. In order to curb its spread and reduce morbidity and mortality, it is essential to develop sensitive and quantitative methods that identify infected individuals and enable accurate population-wide screening of both past and present infection. Here we show that Single Molecule Array assays detect seroconversion in COVID-19 patients as soon as one day after symptom onset using less than a microliter of blood. This multiplexed assay format allows us to quantitate IgG, IgM and IgA immunoglobulins against four SARS-CoV-2 targets, thereby interrogating 12 antibody isotype-viral protein interactions to give a high resolution profile of the immune response. Using a cohort of samples collected prior to the outbreak as well as samples collected during the pandemic, we demonstrate a sensitivity of 86% and a specificity of 100% during the first week of infection, and 100% sensitivity and specificity thereafter. This assay should become the gold standard for COVID19 serological profiling and will be a valuable tool for answering important questions about the heterogeneity of clinical presentation seen in the ongoing pandemic.

19.
Nat Biomed Eng ; 4(12): 1180-1187, 2020 12.
Article in English | MEDLINE | ID: covidwho-780007

ABSTRACT

Sensitive assays are essential for the accurate identification of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we report a multiplexed assay for the fluorescence-based detection of seroconversion in infected individuals from less than 1 µl of blood, and as early as the day of the first positive nucleic acid test after symptom onset. The assay uses dye-encoded antigen-coated beads to quantify the levels of immunoglobulin G (IgG), IgM and IgA antibodies against four SARS-CoV-2 antigens. A logistic regression model trained using samples collected during the pandemic and samples collected from healthy individuals and patients with respiratory infections before the first outbreak of coronavirus disease 2019 (COVID-19) was 99% accurate in the detection of seroconversion in a blinded validation cohort of samples collected before the pandemic and from patients with COVID-19 five or more days after a positive nasopharyngeal test by PCR with reverse transcription. The high-throughput serological profiling of patients with COVID-19 allows for the interrogation of interactions between antibody isotypes and viral proteins, and should help us to understand the heterogeneity of clinical presentations.


Subject(s)
COVID-19/immunology , Immunoassay/methods , Seroconversion/physiology , Aged , Aged, 80 and over , Antibodies/immunology , Humans , Immunoglobulin G/immunology , Male , Middle Aged , Pandemics/prevention & control , SARS-CoV-2/immunology , Sensitivity and Specificity
20.
Clin Chem ; 66(12): 1562-1572, 2020 12 01.
Article in English | MEDLINE | ID: covidwho-748361

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 21 million people worldwide since August 16, 2020. Compared to PCR and serology tests, SARS-CoV-2 antigen assays are underdeveloped, despite their potential to identify active infection and monitor disease progression. METHODS: We used Single Molecule Array (Simoa) assays to quantitatively detect SARS-CoV-2 spike, S1 subunit, and nucleocapsid antigens in the plasma of patients with coronavirus disease (COVID-19). We studied plasma from 64 patients who were COVID-19 positive, 17 who were COVID-19 negative, and 34 prepandemic patients. Combined with Simoa anti-SARS-CoV-2 serological assays, we quantified changes in 31 SARS-CoV-2 biomarkers in 272 longitudinal plasma samples obtained for 39 patients with COVID-19. Data were analyzed by hierarchical clustering and were compared to longitudinal RT-PCR test results and clinical outcomes. RESULTS: SARS-CoV-2 S1 and N antigens were detectable in 41 out of 64 COVID-19 positive patients. In these patients, full antigen clearance in plasma was observed a mean ± 95% CI of 5 ± 1 days after seroconversion and nasopharyngeal RT-PCR tests reported positive results for 15 ± 5 days after viral-antigen clearance. Correlation between patients with high concentrations of S1 antigen and ICU admission (77%) and time to intubation (within 1 day) was statistically significant. CONCLUSIONS: The reported SARS-CoV-2 Simoa antigen assay is the first to detect viral antigens in the plasma of patients who were COVID-19 positive to date. These data show that SARS-CoV-2 viral antigens in the blood are associated with disease progression, such as respiratory failure, in COVID-19 cases with severe disease.


Subject(s)
Antibodies, Viral/blood , Antigens, Viral/blood , COVID-19/diagnosis , Disease Progression , SARS-CoV-2/chemistry , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , COVID-19/blood , COVID-19 Serological Testing , Coronavirus Nucleocapsid Proteins/blood , Female , Hospitalization , Humans , Intensive Care Units , Intubation , Limit of Detection , Male , Middle Aged , Phosphoproteins/blood , Prognosis , Protein Subunits/blood , Spike Glycoprotein, Coronavirus/blood
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