Five Commercial Immunoassays for SARS-CoV-2 Antibody Determination and Their Comparison and Correlation with the Virus Neutralization Test.

Václav Šimánek,Tomáš Fürst,Ladislav Pecen,Robin Šín,Karel Fajfrlík,Radek Kučera,Hana Řezáčková,Dalibor Sedláček,David Slouka,Ondřej Topolčan,Zuzana Krátká,Petr Pazdiora,Hana Zelená

doi:10.3390/diagnostics11040593

Abstract

There is an ongoing debate as to whether SARS-CoV-2 antibodies can be found in patients who have recovered from COVID-19 disease. Currently, there is no consensus on whether the antibodies, if present, are protective. Our regular measurements of SARS-CoV-2 antibodies, starting in July 2020, have provided us with the opportunity of becoming acquainted with the five different immunoassays. A total of 149 patients were enrolled in our study. We measured the samples using each immunoassay, then performing a virus neutralization test and comparing the results of SARS-CoV-2 antibodies with this test. We observed that the production of neutralizing antibodies is age-dependent. Elderly patients have a higher proportion of high neutralizing titers than young patients. Based on our results, and in combination with the literature findings, we can conclude that the serological SARS-CoV-2 antibody measurement is a helpful tool in the fight against COVID-19. The assays can provide information about the patient’s previous contact with the virus. Anti-spike protein assays correlate well with the virus neutralization test and can be used in the screening of potential convalescent plasma donors.

Highlights

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which causes the coronavirus disease 2019 (COVID-19), was first detected in Wuhan, China, in November 2019 [1]
The results of the virus neutralization test (VNT) were expressed in the form of virus neutralization titer, which represents an inverted value of the highest dilution of the sample neutralizing the cytopathic effect of the virus for more than 50%
After correlation with VNT, we suggested two cut-off levels for each immunoassay corresponding to the titers 80 and 160, respectively

Summary

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which causes the coronavirus disease 2019 (COVID-19), was first detected in Wuhan, China, in November 2019 [1]. The SARS-CoV-2 virus has infected over 100 million individuals with 2.5 million deaths globally and has caused a pandemic which has affected almost every country worldwide [2]. There is an ongoing debate as to whether SARS-CoV-2 antibodies can be found in patients who have recovered from COVID-19 disease. Detecting antibodies allows us to confirm that the person was in contact with the virus and developed an immune response against the coronavirus infection. Such a person has a higher likelihood of being protected against a future infection. Clinical experience gained from studying patients who have been reinfected with other types of coronaviruses indicated that in the 6–12 months following the first infection, the viral load was lower, the period of virus shedding was shorter than in the previous infection, the course of the disease was much weaker, or the disease did not develop [6,7]

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