Comparative performance of five commercially available serologic assays to detect antibodies to SARS-CoV-2 and identify individuals with high neutralizing titers.
21 Jan 2021-Journal of Clinical Microbiology (American Society for Microbiology)-Vol. 59, Iss: 2, pp 21
TL;DR: The diagnostic accuracy of five commercially available EIAs (Abbott, Euroimmun, EDI, ImmunoDiagnostics, and Roche) for detection of IgG or total antibodies to SARS-CoV-2 and neutralizing antibodies (nAbs) was evaluated.
Abstract: Accurate serological assays to detect antibodies to SARS-CoV-2 are needed to characterize the epidemiology of SARS-CoV-2 infection and identify potential candidates for COVID-19 convalescent plasma (CCP) donation. This study compared the performance of commercial enzyme immunoassays (EIAs) to detect IgG or total antibodies to SARS-CoV-2 and neutralizing antibodies (nAb). The diagnostic accuracy of five commercially available EIAs (Abbott, Euroimmun, EDI, ImmunoDiagnostics, and Roche) to detect IgG or total antibodies to SARS-CoV-2 was evaluated from cross-sectional samples of potential CCP donors that had prior molecular confirmation of SARS-CoV-2 infection (n=214) and pre-pandemic emergency department patients without SARS-CoV-2 infection (n=1,099). Of the 214 potential CCP donors, all were sampled >14 days since symptom onset and only a minority had been hospitalized due to COVID-19 (n=16 [7.5%]); 140 potential CCP donors were tested by all five EIAs and a microneutralization assay. When performed according to the manufacturers' protocol to detect IgG or total antibodies to SARS-CoV-2, the sensitivity of each EIA ranged from 76.4% to 93.9%, and the specificity of each EIA ranged from 87.0% to 99.6%. Using a nAb titer cutoff of ≥160 as the reference positive test (n=140 CCP donors), the empirical area under receiver operating curve of each EIA ranged from 0.66 (Roche) to 0.90 (Euroimmun). Commercial EIAs with high diagnostic accuracy to detect SARS-CoV-2 antibodies did not necessarily have high diagnostic accuracy to detect high nAbs. Some but not all commercial EIAs may be useful in the identification of individuals with high nAbs in convalescent individuals.
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TL;DR: In this article, the antibody response following the second dose of SARS-CoV2 mRNA vaccine in recipients of solid organ transplants was measured using a follow-up study.
Abstract: This follow-up study measures the antibody response following the second dose of SARS-CoV-2 mRNA vaccine in recipients of solid organ transplants.
745 citations
TL;DR: In this article, the authors quantified antispike protein antibody responses to first-dose messenger RNA (mRNA) COVID-19 vaccines in solid organ transplant recipients to better understand the immunogenicity of the vaccines in immunocompromised individuals.
Abstract: This study quantifies antispike protein antibody responses to first-dose messenger RNA (mRNA) COVID-19 vaccines in solid organ transplant recipients to better understand the immunogenicity of the vaccines in immunocompromised individuals.
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TL;DR: In this article, the authors evaluated the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19 and found no significant difference in 28-day mortality between the two groups.
383 citations
TL;DR: Modelling demonstrated a coordinated and dynamic immune response characterized by a decrease in inflammation, increase in neutralizing antibody titer, and differentiation of a specific CD8+ T cell response.
Abstract: Characterization of the T cell response in individuals who recover from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is critical to understanding its contribution to protective immunity. A multiplexed peptide-MHC tetramer approach was used to screen 408 SARS-CoV-2 candidate epitopes for CD8+ T cell recognition in a cross-sectional sample of 30 coronavirus disease 2019 convalescent individuals. T cells were evaluated using a 28-marker phenotypic panel, and findings were modelled against time from diagnosis and from humoral and inflammatory responses. There were 132 SARS-CoV-2-specific CD8+ T cell responses detected across 6 different HLAs, corresponding to 52 unique epitope reactivities. CD8+ T cell responses were detected in almost all convalescent individuals and were directed against several structural and nonstructural target epitopes from the entire SARS-CoV-2 proteome. A unique phenotype for SARS-CoV-2-specific T cells was observed that was distinct from other common virus-specific T cells detected in the same cross-sectional sample and characterized by early differentiation kinetics. Modelling demonstrated a coordinated and dynamic immune response characterized by a decrease in inflammation, increase in neutralizing antibody titer, and differentiation of a specific CD8+ T cell response. Overall, T cells exhibited distinct differentiation into stem cell and transitional memory states (subsets), which may be key to developing durable protection.
178 citations
TL;DR: In this paper, the authors reviewed the latest knowledge on humoral immune responses to SARS-CoV-2 infection, along with the benefits and limitations of currently available commercial and laboratory-based serological assays.
Abstract: In December 2019, the novel betacoronavirus Severe Acute Respiratory Disease Coronavirus 2 (SARS-CoV-2) was first detected in Wuhan, China. SARS-CoV-2 has since become a pandemic virus resulting in hundreds of thousands of deaths and deep socioeconomic implications worldwide. In recent months, efforts have been directed towards detecting, tracking, and better understanding human humoral responses to SARS-CoV-2 infection. It has become critical to develop robust and reliable serological assays to characterize the abundance, neutralization efficiency, and duration of antibodies in virus-exposed individuals. Here we review the latest knowledge on humoral immune responses to SARS-CoV-2 infection, along with the benefits and limitations of currently available commercial and laboratory-based serological assays. We also highlight important serological considerations, such as antibody expression levels, stability and neutralization dynamics, as well as cross-reactivity and possible immunological back-boosting by seasonal coronaviruses. The ability to accurately detect, measure and characterize the various antibodies specific to SARS-CoV-2 is necessary for vaccine development, manage risk and exposure for healthcare and at-risk workers, and for monitoring reinfections with genetic variants and new strains of the virus. Having a thorough understanding of the benefits and cautions of standardized serological testing at a community level remains critically important in the design and implementation of future vaccination campaigns, epidemiological models of immunity, and public health measures that rely heavily on up-to-date knowledge of transmission dynamics.
157 citations
References
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TL;DR: The outbreak of the 2019 novel coronavirus disease (COVID-19) has induced a considerable degree of fear, emotional stress and anxiety among individuals around the world.
Abstract: The outbreak of the 2019 novel coronavirus disease (COVID-19) has induced a considerable degree of fear, emotional stress and anxiety among individuals around t
8,336 citations
TL;DR: It is shown that a TMPRSS2-expressing VeroE6 cell line is highly susceptible to Sars-CoV-2 infection, making it useful for isolating and propagating SARS-Cov-2.
Abstract: A novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which caused a large respiratory outbreak in Wuhan, China in December 2019, is currently spreading across many countries globally. Here, we show that a TMPRSS2-expressing VeroE6 cell line is highly susceptible to SARS-CoV-2 infection, making it useful for isolating and propagating SARS-CoV-2. Our results reveal that, in common with SARS- and Middle East respiratory syndrome-CoV, SARS-CoV-2 infection is enhanced by TMPRSS2.
1,139 citations
"Comparative performance of five com..." refers methods in this paper
...After a 1-h incubation at room temperature (19°C), 100 l of each sample dilution was added to 6 wells in a 96-well plate of VeroE6-TMPRSS2 cells (23) and incubated for 6 h at 37°C....
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TL;DR: Higher quality clinical studies assessing the diagnostic accuracy of serological tests for covid-19 are urgently needed, as available evidence does not support the continued use of existing point-of-care serological Tests for coronavirus disease-2019.
Abstract: Objective To determine the diagnostic accuracy of
serological tests for coronavirus disease-2019
(covid-19). Design Systematic review and meta-analysis. Data sources Medline, bioRxiv, and medRxiv from 1 January to
30 April 2020, using subject headings or
subheadings combined with text words for the
concepts of covid-19 and serological tests for
covid-19. Eligibility criteria and data
analysis Eligible studies measured sensitivity or
specificity, or both of a covid-19 serological
test compared with a reference standard of viral
culture or reverse transcriptase polymerase chain
reaction. Studies were excluded with fewer than
five participants or samples. Risk of bias was
assessed using quality assessment of diagnostic
accuracy studies 2 (QUADAS-2). Pooled sensitivity
and specificity were estimated using random
effects bivariate meta-analyses. Main outcome measures The primary outcome was overall sensitivity and
specificity, stratified by method of serological
testing (enzyme linked immunosorbent assays
(ELISAs), lateral flow immunoassays (LFIAs), or
chemiluminescent immunoassays (CLIAs)) and
immunoglobulin class (IgG, IgM, or both).
Secondary outcomes were stratum specific
sensitivity and specificity within subgroups
defined by study or participant characteristics,
including time since symptom onset. Results 5016 references were identified and 40 studies
included. 49 risk of bias assessments were carried
out (one for each population and method
evaluated). High risk of patient selection bias
was found in 98% (48/49) of assessments and high
or unclear risk of bias from performance or
interpretation of the serological test in 73%
(36/49). Only 10% (4/40) of studies included
outpatients. Only two studies evaluated tests at
the point of care. For each method of testing,
pooled sensitivity and specificity were not
associated with the immunoglobulin class measured.
The pooled sensitivity of ELISAs measuring IgG or
IgM was 84.3% (95% confidence interval 75.6% to
90.9%), of LFIAs was 66.0% (49.3% to 79.3%), and
of CLIAs was 97.8% (46.2% to 100%). In all
analyses, pooled sensitivity was lower for LFIAs,
the potential point-of-care method. Pooled
specificities ranged from 96.6% to 99.7%. Of the
samples used for estimating specificity, 83%
(10 465/12 547) were from populations tested
before the epidemic or not suspected of having
covid-19. Among LFIAs, pooled sensitivity of
commercial kits (65.0%, 49.0% to 78.2%) was lower
than that of non-commercial tests (88.2%, 83.6% to
91.3%). Heterogeneity was seen in all analyses.
Sensitivity was higher at least three weeks after
symptom onset (ranging from 69.9% to 98.9%)
compared with within the first week (from 13.4% to
50.3%). Conclusion Higher quality clinical studies assessing the
diagnostic accuracy of serological tests for
covid-19 are urgently needed. Currently, available
evidence does not support the continued use of
existing point-of-care serological tests. Study registration PROSPERO CRD42020179452.
703 citations
TL;DR: An overview of convalescent plasma is provided, from evidence of benefit, regulatory considerations, logistical work flow and proposed clinical trials, as scale up is brought underway to mobilize this critical resource.
Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), has spurred a global health crisis. To date, there are no proven options for prophylaxis for those who have been exposed to SARS-CoV-2, nor therapy for those who develop COVID-19. Immune (i.e., "convalescent") plasma refers to plasma that is collected from individuals following resolution of infection and development of antibodies. Passive antibody administration through transfusion of convalescent plasma may offer the only short-term strategy for conferring immediate immunity to susceptible individuals. There are numerous examples in which convalescent plasma has been used successfully as postexposure prophylaxis and/or treatment of infectious diseases, including other outbreaks of coronaviruses (e.g., SARS-1, Middle East respiratory syndrome [MERS]). Convalescent plasma has also been used in the COVID-19 pandemic; limited data from China suggest clinical benefit, including radiological resolution, reduction in viral loads, and improved survival. Globally, blood centers have robust infrastructure for undertaking collections and constructing inventories of convalescent plasma to meet the growing demand. Nonetheless, there are nuanced challenges, both regulatory and logistical, spanning donor eligibility, donor recruitment, collections, and transfusion itself. Data from rigorously controlled clinical trials of convalescent plasma are also few, underscoring the need to evaluate its use objectively for a range of indications (e.g., prevention vs. treatment) and patient populations (e.g., age, comorbid disease). We provide an overview of convalescent plasma, including evidence of benefit, regulatory considerations, logistical work flow, and proposed clinical trials, as scale-up is brought underway to mobilize this critical resource.
689 citations
"Comparative performance of five com..." refers background in this paper
...Commercial SARS-CoV-2 EIAs may have an additional role in the implementation of COVID-19 convalescent plasma (CCP) therapy programs (2, 9, 10)....
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TL;DR: To assess the diagnostic accuracy of antibody tests to determine if a person presenting in the community or in primary or secondary care has SARS-CoV-2 infection, or has previously had SARS, and the accuracy of antibodies for use in seroprevalence surveys is assessed.
Abstract: Background The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus and resulting COVID-19 pandemic present important diagnostic challenges. Several diagnostic strategies are available to identify current infection, rule out infection, identify people in need of care escalation, or to test for past infection and immune response. Serology tests to detect the presence of antibodies to SARS-CoV-2 aim to identify previous SARS-CoV-2 infection, and may help to confirm the presence of current infection. Objectives To assess the diagnostic accuracy of antibody tests to determine if a person presenting in the community or in primary or secondary care has SARS-CoV-2 infection, or has previously had SARS-CoV-2 infection, and the accuracy of antibody tests for use in seroprevalence surveys. Search methods We undertook electronic searches in the Cochrane COVID-19 Study Register and the COVID-19 Living Evidence Database from the University of Bern, which is updated daily with published articles from PubMed and Embase and with preprints from medRxiv and bioRxiv. In addition, we checked repositories of COVID-19 publications. We did not apply any language restrictions. We conducted searches for this review iteration up to 27 April 2020. Selection criteria We included test accuracy studies of any design that evaluated antibody tests (including enzyme-linked immunosorbent assays, chemiluminescence immunoassays, and lateral flow assays) in people suspected of current or previous SARS-CoV-2 infection, or where tests were used to screen for infection. We also included studies of people either known to have, or not to have SARS-CoV-2 infection. We included all reference standards to define the presence or absence of SARS-CoV-2 (including reverse transcription polymerase chain reaction tests (RT-PCR) and clinical diagnostic criteria). Data collection and analysis We assessed possible bias and applicability of the studies using the QUADAS-2 tool. We extracted 2x2 contingency table data and present sensitivity and specificity for each antibody (or combination of antibodies) using paired forest plots. We pooled data using random-effects logistic regression where appropriate, stratifying by time since post-symptom onset. We tabulated available data by test manufacturer. We have presented uncertainty in estimates of sensitivity and specificity using 95% confidence intervals (CIs). Main results We included 57 publications reporting on a total of 54 study cohorts with 15,976 samples, of which 8526 were from cases of SARS-CoV-2 infection. Studies were conducted in Asia (n = 38), Europe (n = 15), and the USA and China (n = 1). We identified data from 25 commercial tests and numerous in-house assays, a small fraction of the 279 antibody assays listed by the Foundation for Innovative Diagnostics. More than half (n = 28) of the studies included were only available as preprints. We had concerns about risk of bias and applicability. Common issues were use of multi-group designs (n = 29), inclusion of only COVID-19 cases (n = 19), lack of blinding of the index test (n = 49) and reference standard (n = 29), differential verification (n = 22), and the lack of clarity about participant numbers, characteristics and study exclusions (n = 47). Most studies (n = 44) only included people hospitalised due to suspected or confirmed COVID-19 infection. There were no studies exclusively in asymptomatic participants. Two-thirds of the studies (n = 33) defined COVID-19 cases based on RT-PCR results alone, ignoring the potential for false-negative RT-PCR results. We observed evidence of selective publication of study findings through omission of the identity of tests (n = 5). We observed substantial heterogeneity in sensitivities of IgA, IgM and IgG antibodies, or combinations thereof, for results aggregated across different time periods post-symptom onset (range 0% to 100% for all target antibodies). We thus based the main results of the review on the 38 studies that stratified results by time since symptom onset. The numbers of individuals contributing data within each study each week are small and are usually not based on tracking the same groups of patients over time. Pooled results for IgG, IgM, IgA, total antibodies and IgG/IgM all showed low sensitivity during the first week since onset of symptoms (all less than 30.1%), rising in the second week and reaching their highest values in the third week. The combination of IgG/IgM had a sensitivity of 30.1% (95% CI 21.4 to 40.7) for 1 to 7 days, 72.2% (95% CI 63.5 to 79.5) for 8 to 14 days, 91.4% (95% CI 87.0 to 94.4) for 15 to 21 days. Estimates of accuracy beyond three weeks are based on smaller sample sizes and fewer studies. For 21 to 35 days, pooled sensitivities for IgG/IgM were 96.0% (95% CI 90.6 to 98.3). There are insufficient studies to estimate sensitivity of tests beyond 35 days post-symptom onset. Summary specificities (provided in 35 studies) exceeded 98% for all target antibodies with confidence intervals no more than 2 percentage points wide. False-positive results were more common where COVID-19 had been suspected and ruled out, but numbers were small and the difference was within the range expected by chance. Assuming a prevalence of 50%, a value considered possible in healthcare workers who have suffered respiratory symptoms, we would anticipate that 43 (28 to 65) would be missed and 7 (3 to 14) would be falsely positive in 1000 people undergoing IgG/IgM testing at days 15 to 21 post-symptom onset. At a prevalence of 20%, a likely value in surveys in high-risk settings, 17 (11 to 26) would be missed per 1000 people tested and 10 (5 to 22) would be falsely positive. At a lower prevalence of 5%, a likely value in national surveys, 4 (3 to 7) would be missed per 1000 tested, and 12 (6 to 27) would be falsely positive. Analyses showed small differences in sensitivity between assay type, but methodological concerns and sparse data prevent comparisons between test brands. Authors' conclusions The sensitivity of antibody tests is too low in the first week since symptom onset to have a primary role for the diagnosis of COVID-19, but they may still have a role complementing other testing in individuals presenting later, when RT-PCR tests are negative, or are not done. Antibody tests are likely to have a useful role for detecting previous SARS-CoV-2 infection if used 15 or more days after the onset of symptoms. However, the duration of antibody rises is currently unknown, and we found very little data beyond 35 days post-symptom onset. We are therefore uncertain about the utility of these tests for seroprevalence surveys for public health management purposes. Concerns about high risk of bias and applicability make it likely that the accuracy of tests when used in clinical care will be lower than reported in the included studies. Sensitivity has mainly been evaluated in hospitalised patients, so it is unclear whether the tests are able to detect lower antibody levels likely seen with milder and asymptomatic COVID-19 disease. The design, execution and reporting of studies of the accuracy of COVID-19 tests requires considerable improvement. Studies must report data on sensitivity disaggregated by time since onset of symptoms. COVID-19-positive cases who are RT-PCR-negative should be included as well as those confirmed RT-PCR, in accordance with the World Health Organization (WHO) and China National Health Commission of the People's Republic of China (CDC) case definitions. We were only able to obtain data from a small proportion of available tests, and action is needed to ensure that all results of test evaluations are available in the public domain to prevent selective reporting. This is a fast-moving field and we plan ongoing updates of this living systematic review.
651 citations