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3.
Journal of Allergy and Clinical Immunology ; 147(2):AB77-AB77, 2021.
Article in English | PMC | ID: covidwho-1385784

ABSTRACT

Rationale: Point-of-care (POC) antibody screening for SARS-CoV-2 infection has yielded varied results. We analyzed two POC antibody testing devices to study whether these are comparable to ELISA testing done in a high complexity CLIA facility employed as a standard. Methods: We enrolled 146 individuals, with 41 individuals having had a history of positive PCR for COVID-19. After informed consent, we obtained serum and at the same time performed a finger stick for whole blood. Autobio and MEDsan rapid IgG/IgM tests that use SARS-CoV-2 spike protein to detect antibody were performed with serum and compared to Roche’s SARS-CoV-2 immunoassay, which uses nucleocapsid protein to detect antibody. The Autobio test was also evaluated using whole blood obtained by finger stick. Results: Serum testing using the Autobio kit versus the Roche immunoassay (used as the standard for comparison) revealed a sensitivity of 93.2% and a specificity of 96.1%;whole blood testing using the Autobio kit vs. the Roche immunoassay revealed a sensitivity of 90.5% and a specificity of 97.9%. Whole blood compared to serum testing using the Autobio POC kit revealed a sensitivity of 90.7% and a specificity of 99.0%. Serum testing using the MEDsan kit vs. the Roche immunoassay revealed a sensitivity of 100% and a specificity of 96.1%. Conclusions: Despite using different antigens, both the POC devices showed comparable results to the high complexity ELISA. POC testing for antibodies to SARS-CoV-2 is easier, requires fewer resources than high-complexity lab testing and provides rapid results regarding individual antibody status to SARS-CoV-2. However, the specific test characteristics for each kit must be rigorously evaluated, as they vary substantially.

4.
Microbiol Spectr ; 9(2): e0008721, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1381168

ABSTRACT

Uncertainty exists whether mild COVID-19 confers immunity to reinfection. Questions also remain regarding the persistence of antibodies against SARS-CoV-2 after mild infection. We prospectively followed at-risk individuals with and without SARS-CoV-2 for reinfection and monitored the spike and nucleocapsid antibodies. This prospective cohort study was conducted over two visits, 3 to 6 months apart, between May 2020 and February 2021. Adults with and without COVID-19, verified by FDA EUA-approved SARS-CoV-2 RT-PCR assays, were screened for spike and nucleocapsid antibody responses using FDA EUA-approved immunoassays and for pseudoviral neutralization activity. The subjects were monitored for symptoms, exposure to COVID-19, COVID-19 testing, seroconversion, reinfection, and vaccination. A total of 653 subjects enrolled; 129 (20%) had a history of COVID-19 verified by RT-PCR at enrollment. Most had mild disease, with only three requiring hospitalization. No initially seropositive subjects experienced a subsequent COVID-19 infection during the follow-up versus 15 infections among initially seronegative subjects (infection rates of 0.00 versus 2.05 per 10,000 days at risk [P = 0.0485]). In all, 90% of SARS-CoV-2-positive subjects produced spike and nucleocapsid responses, and all but one of these had persistent antibody levels at follow-up. Pseudoviral neutralization activity was widespread among participants, did not decrease over time, and correlated with clinical antibody assays. Reinfection with SARS-CoV-2 was not observed among individuals with mild clinical COVID-19, while infections continued in a group without known prior infection. Spike and nucleocapsid COVID-19 antibodies were associated with almost all infections and persisted at stable levels for the study duration. IMPORTANCE This article demonstrates that people who have mild COVID-19 illnesses and produce antibodies are protected from reinfection for up to 6 months afterward. The antibodies that people produce in this situation are stable for up to 6 months as well. Clinical antibody assays correlate well with evidence of antibody-related viral neutralization activity.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/prevention & control , Coronavirus Nucleocapsid Proteins/immunology , Reinfection/prevention & control , Spike Glycoprotein, Coronavirus/immunology , Adult , COVID-19/immunology , COVID-19 Testing , Female , Humans , Immunoassay , Male , Phosphoproteins/immunology , Prospective Studies , Reinfection/immunology , SARS-CoV-2/immunology
5.
Proc Natl Acad Sci U S A ; 118(27)2021 07 06.
Article in English | MEDLINE | ID: covidwho-1276013

ABSTRACT

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a key role in viral infectivity. It is also the major antigen stimulating the host's protective immune response, specifically, the production of neutralizing antibodies. Recently, a new variant of SARS-CoV-2 possessing multiple mutations in the S protein, designated P.1, emerged in Brazil. Here, we characterized a P.1 variant isolated in Japan by using Syrian hamsters, a well-established small animal model for the study of SARS-CoV-2 disease (COVID-19). In hamsters, the variant showed replicative abilities and pathogenicity similar to those of early and contemporary strains (i.e., SARS-CoV-2 bearing aspartic acid [D] or glycine [G] at position 614 of the S protein). Sera and/or plasma from convalescent patients and BNT162b2 messenger RNA vaccinees showed comparable neutralization titers across the P.1 variant, S-614D, and S-614G strains. In contrast, the S-614D and S-614G strains were less well recognized than the P.1 variant by serum from a P.1-infected patient. Prior infection with S-614D or S-614G strains efficiently prevented the replication of the P.1 variant in the lower respiratory tract of hamsters upon reinfection. In addition, passive transfer of neutralizing antibodies to hamsters infected with the P.1 variant or the S-614G strain led to reduced virus replication in the lower respiratory tract. However, the effect was less pronounced against the P.1 variant than the S-614G strain. These findings suggest that the P.1 variant may be somewhat antigenically different from the early and contemporary strains of SARS-CoV-2.


Subject(s)
COVID-19/virology , SARS-CoV-2/physiology , SARS-CoV-2/pathogenicity , Virus Replication , Animals , Antibodies, Neutralizing , COVID-19/diagnostic imaging , COVID-19/pathology , Cricetinae , Humans , Immunogenicity, Vaccine , Lung/pathology , Mesocricetus , Mice , Spike Glycoprotein, Coronavirus/genetics , X-Ray Microtomography
6.
PLoS One ; 16(3): e0248729, 2021.
Article in English | MEDLINE | ID: covidwho-1136300

ABSTRACT

BACKGROUND: As COVID-19 vaccines become available, screening individuals for prior COVID-19 infection and vaccine response in point-of-care (POC) settings has renewed interest. We prospectively screened at-risk individuals for SARS-CoV-2 spike and nucleocapsid protein antibodies in a POC setting to determine if it was a feasible method to identify antibody from prior infection. METHODS: Three EUA-approved lateral flow antibody assays were performed on POC finger-stick blood and compared with serum and a CLIA nucleocapsid antibody immunoassay. Variables including antibody class, time since PCR, and the assay antigen used were evaluated. RESULTS: 512 subjects enrolled, of which 104 had a COVID-19 history and positive PCR. Only three PCR-positive subjects required hospitalization, with one requiring mechanical ventilation. The POC results correlated well with the immunoassay (93-97% sensitivity) and using serum did not improve the sensitivity or specificity. CONCLUSIONS: Finger-stick, POC COVID-19 antibody testing was highly effective in identifying antibody resulting from prior infections in mildly symptomatic subjects. Using high-complexity serum immunoassays did not improve the screening outcome. Almost all individuals with COVID-19 infection produced detectable antibodies to the virus. POC antibody testing is useful as a screen for prior COVID-19 infection, and should be useful in assessing vaccine response.


Subject(s)
COVID-19/diagnosis , Point-of-Care Systems , Adult , Aged , Antibodies, Viral/blood , COVID-19/virology , COVID-19 Serological Testing , Female , Humans , Immunoassay , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Nucleocapsid/immunology , Reagent Kits, Diagnostic , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Young Adult
8.
Am J Clin Pathol ; 155(2): 267-279, 2021 02 04.
Article in English | MEDLINE | ID: covidwho-841691

ABSTRACT

OBJECTIVES: Serologic testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has experienced a changing landscape of available assays coupled with uncertainty surrounding performance characteristics. Studies are needed to directly compare multiple commercially available assays. METHODS: Residual serum samples were identified based on SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) testing, clinical test results, and collection dates. Serum samples were analyzed using assays from four different manufacturers: DiaSorin anti-SARS-CoV-2 S1/S2 IgG, EUROIMMUN anti-SARS-CoV-2 IgG ELISA, Roche Elecsys anti-SARS-CoV-2, and Siemens SARS-CoV-2 Total antibody assays. RESULTS: Samples from SARS-CoV-2 RT-PCR-positive patients became increasingly positive as time from symptom onset increased. For patients with latest sample 14 or more days after symptom onset, sensitivities reached 93.1% to 96.6%, 98.3%, and 96.6% for EUROIMMUN, Roche, and Siemens assays, respectively, which were superior to the DiaSorin assay at 87.7%. The specificity of Roche and Siemens assays was 100% and superior to DiaSorin and EUROIMMUN assays, which ranged from 96.1% to 97.0% and 86.3% to 96.4%, respectively. CONCLUSIONS: Laboratories should be aware of the advantages and limitations of serology testing options for SARS-CoV-2. The specificity and sensitivity achieved by the Roche and Siemens assays would be acceptable for testing in lower-prevalence regions and have the potential of orthogonal testing advantages if used in combination.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , High-Throughput Screening Assays/methods , SARS-CoV-2/immunology , Female , Humans , Male , Predictive Value of Tests , Sensitivity and Specificity
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