Becton Dickinson Directigen EZ Flu A+B assay in the diagnosis of pandemic influenza A H1N1 2009 virus infection in adult patients

To the editor: The recent emergence and spread of the pandemic influenza A H1N1 2009 virus demands the evaluation of rapid antigen assays for their ability to detect this novel subtype of influenza A virus. Data on the ability of BD Directigen EZ Flu A+B immunochromatographic (IC) assay (Beckton Dickinson and Company, Sparks, MD, USA) to detect the pandemic influenza A virus strain in fresh clinical samples have been recently published. 1 , 2 , 3 , 4 , 5 In these studies, the majority of specimens were collected from pediatric patients, and the sensitivities reported ranged from 46·8% to 76·6%. As viral shedding in the upper respiratory tract during influenza virus infection is of greater m…

Performance Comparison of a Flow Cytometry-based and Two Commercial Chemiluminescent Immunoassays for Detection and Quantification of Antibodies Binding to SARS-CoV-2 Spike Protein

ABSTRACTThe performance of a laboratory-developed quantitative IgG/IgA flow cytometry-based immunoassay (FCI) using Jurkat T cells stably expressing full-length native S protein was compared against Elecsys® electrochemiluminiscent (ECLIA) Anti-SARS-CoV-2 S (Roche Diagnostics, Pleasanton, CA, USA), and LIAISON® SARS-CoV-2 TrimericS IgG chemiluminiscent assay (CLIA) (Diasorin S.p.a, Saluggia, IT) for detection and quantitation of SARS-CoV-2-specific antibodies. A total of 225 serum/plasma specimens from 120 acute or convalescent COVID-19 individuals were included. Overall, IgG/IgA-FCI yielded the highest number of positives (n=179), followed by IgA-FCI (n=177), Roche ECLIA (n=175), IgG-FCI (…

B and T cell immune responses elicited by the Comirnaty® COVID-19 vaccine in nursing home residents

Objectives The immunogenicity of the Comirnaty® COVID-19 vaccine is understudied in elderly people with comorbidities. SARS-CoV-2-S-targeted antibody and T cell responses following full vaccination were assessed in nursing home residents. Methods Sixty nursing home residents (44 female; age, 53-100 years), of whom 10 had previously been diagnosed of COVID-19, and 18 healthy controls (15 female; age, 27-54 years) were recruited. Pre- and post-vaccination blood specimens were available for quantitation of total antibodies binding SARS-CoV-2 S protein and enumeration of SARS-CoV-2-S-reactive IFN-γ CD4+ and CD8+ T cells by flow cytometry. Results The seroconversion rate in presumably SARS-CoV-2…

Amplification of human β-glucoronidase gene for appraising the accuracy of negative SARS-CoV-2 RT-PCR results in upper respiratory tract specimens

Real-time reverse transcription polymerase-chain reaction (RT-PCR) is the mainstay of Covid-19 diagnosis. False-negative RT-PCR results may hamper clinical management of patients and hinder the adoption of epidemiological measures to control the pandemic. The current study was aimed at assessing whether amplification of β-glucoronidase (GUSB) gene would help estimate the accuracy of SARS-CoV-2 RT-PCR negative results in upper respiratory tract (URT) specimens. URT specimens that tested negative by SARS-CoV-2 RT-PCR displayed higher GUSB RT-PCR cycle thresholds (CT) (P=0.070) than those testing positive (median, 30.7; range, 27.0-40.0, and median 29.7; range 25.5-36.8, respectively), this re…

Diagnostic significance of SARS-CoV-2 IgM positive/IgG negative antibody profile in symptomatic patients with suspected COVID-19 testing negative by RT-PCR

An outbreak of new coronavirus SARS-CoV-2 was occurred in Wuhan, China and rapidly spread to other cities and nations. The standard diagnostic approach that widely adopted in the clinic is nucleic acid detection by real-time RT-PCR. However, the false-negative rate of the technique is unneglectable and serological methods are urgently warranted. Here, we presented the colloidal gold-based immunochromatographic (ICG) strip targeting viral IgM or IgG antibody and compared it with real-time RT-PCR. The sensitivity of ICG assay with IgM and IgG combinatorial detection in nucleic acid confirmed cases were 11.1%, 92.9% and 96.8% at the early stage (1-7 days after onset), intermediate stage (8-14 …

Immunological response against SARS-CoV-2 following full-dose administration of Comirnaty® COVID-19 vaccine in nursing home residents

6 páginas, 2 figuras, 3 tablas. Se puede acceder al texto completo de este artículo desde PubMedCentral: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8490129 . Los datos de investigación utilizados en el mismo, se encuentran disponibles en: https://doi.org/10.1016/j.cmi.2021.09.031.

Qualitative assessment of SARS-CoV-2-specific antibody avidity by lateral flow immunochromatographic IgG/IgM antibody assay.

Abstract Knowledge of the precise timing of SARS‐CoV‐2 infection may be of clinical and epidemiological relevance. The presence of low‐avidity IgGs has conventionally been considered an indicator of recent infection. Here, we carried out qualitative assessment of SARS‐CoV‐2‐specific antibody avidity using an urea (6M) dissociation test performed on a lateral flow immunochromatographic IgG/IgM device. We included a total of 76 serum specimens collected from 57 COVID‐19 patients, of which 39 tested positive for both IgG and IgM and 37 only for IgG. Sera losing IgG reactivity after urea treatment (n = 28) were drawn significantly earlier (P = .04) after onset of symptoms than those which prese…

Inference of SARS-CoV-2 spike-binding neutralizing antibody titers in sera from hospitalized COVID-19 patients by using commercial enzyme and chemiluminescent immunoassays

medRxiv: https://doi.org/10.1101/2020.09.07.20188151

Caveats in interpreting SARS‐CoV‐2 IgM + /IgG − antibody profile in asymptomatic health care workers

Serological testing is increasingly recognized as a useful tool for management of the COVID‐19 pandemic.1 Cross‐sectional serosurveys provide information on exposure levels in a target population, which is helpful for designing public health strategies to blunt community transmission.2 This article is protected by copyright. All rights reserved.

SARS‐CoV‐2‐reactive interferon‐γ‐producing CD8+ T cells in patients hospitalized with coronavirus disease 2019

Abstract There is limited information on severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) T‐cell immune responses in patients with coronavirus disease 2019 (COVID‐19). Both CD4+ and CD8+ T cells may be instrumental in resolution of and protection from SARS‐CoV‐2 infection. Here, we tested 25 hospitalized patients either with microbiologically documented COVID‐19 (n = 19) or highly suspected of having the disease (n = 6) for presence of SARS‐CoV‐2‐reactive CD69+ expressing interferon‐γ (IFN‐γ) producing CD8+ T cells using flow‐cytometry for intracellular cytokine staining assay. Two sets of overlapping peptides encompassing the SARS‐CoV‐2 Spike glycoprotein N‐terminal 1 to 643 am…

B and T cell immune responses elicited by the BNT162b2 (Pfizer–BioNTech) COVID-19 vaccine in nursing home residents

ABSTRACTObjectivesThe immunogenicity of the BNT162b2 COVID-19 vaccine is understudied in elderly people with comorbidities. We assessed SARS-CoV-2-S-targeted antibody and T cell responses following full vaccination in nursing home residents (NHR).MethodsWe recruited 60 NHR (44 female; median age, 87.5 years), of whom 10 had previously had COVID-19, and 18 healthy controls (15 female; median age, 48.5 years). Pre- and post-vaccination blood specimens were available for quantitation of total antibodies binding RBD and enumeration of SARS-CoV-2-S-reactive IFN-γ CD4+ and CD8+ T cells by flow cytometry.ResultsThe seroconversion rate in presumably SARS-CoV-2 naïve NHR (95.3%), either with or with…

Hepatitis E virus in lettuce and water samples: A method-comparison study

The hepatitis E virus (HEV), which is an increasing cause of acute viral hepatitis in Europe, is a zoonotic virus that is mainly transmitted through contaminated water, consumption of raw or undercooked meat from pigs or wild boar, blood transfusion, and organ transplantation. Although the role of HEV transmission through contaminated produce has not been confirmed, the presence of HEV has been reported in irrigation waters and in vegetables. The present study used a World Health Organization (WHO) international standard and clinical samples to evaluate the performance characteristics of three RT-qPCR assays for detection and quantification of HEV. Two of the evaluated assays provided good …

SARS-CoV-2-reactive interferon-γ-producing CD8+ T cells in patients hospitalized with Coronavirus viral disease-2019

There is limited information on SARS-CoV-2 T-cell immune responses in patients with Covid-19. Both CD4+ and CD8+ T cells may be instrumental in the resolution of and protection from SARS-CoV-2 infection. Here, we tested 25 hospitalized patients with either microbiologically documented Covid-19 (n=19) or highly suspected of having the disease (n=6) for the presence of SARS-CoV-2-reactive- CD69+-expressing interferon-gamma;-producing-(IFN-gamma;) CD8+ T cells by a flow-cytometry for intracelular cytokine staining assay. Two sets of overlapping peptides encompassing the SARS-CoV-2 Spike glycoprotein N-terminal 1-643 amino acid sequence and the entire sequence of SARS-CoV-2 M protein were used …

Becton Dickinson Directigen EZ Flu A+B assay in the diagnosis of pandemic influenza A H1N1 2009 virus infection in adult patients

Evolution of SARS-CoV-2 immune responses in nursing home residents following full dose of the Comirnaty® COVID-19 vaccine

ABSTRACTObjectivesThere is scarce information as to the durability of immune responses elicited by the Comirnaty® COVID-19 vaccine in nursing home residents. Here, we assessed SARS-CoV-2-Spike (S)-targeted antibody and functional T cell responses at around 6 months after complete vaccination.MethodsThe sample comprised 46 residents (34 females; age, 60-100 years), of whom 10 had COVID-19 prior to vaccination. Baseline (median of 17.5 days after vaccination) and follow-up (median, 195 days) plasma specimens were available for quantitation of SARS-CoV-2-S antibodies and enumeration of SARS-CoV-2-S-reactive IFN-γ CD4+ and CD8+ T cells by flow cytometry.ResultsIn total, 44/45 participants had d…