Estimating neutralizing activity in vaccinees is crucial for predicting the protective effect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As the plaque reduction neutralization test (PRNT) requires a biosafety level 3 facility, it would be advantageous if surrogate virus neutralization test (sVNT) assays and binding assays could predict neutralizing activity. Here, five different assays were evaluated with respect to the PRNT in vaccinees: three sVNT assays from GenScript, Boditech Med, and SD Biosensor and two semiquantitative binding assays from Roche and Abbott. The vaccinees were subjected to three vaccination protocols: homologous ChAdOx1, homologous BNT162b2, and heterologous administration. The ability to predict a 50% neutralizing dose (ND50) of $20 largely varied among the assays, with the binding assays showing substantial agreement (kappa,;0.90) and the sVNT assays showing relatively poor performance, especially in the ChAdOx1 group (kappa, 0.33 to 0.97). The ability to predict an ND50 value of $118.25, indicating a protective effect, was comparable among different assays. Applying optimal cutoffs based on Youden’s index, the kappa agreements were greater than 0.60 for all assays in the total group. Overall, relatively poor performance was demonstrated in the ChAdOx1 group, owing to low antibody titers. Although there were intra-assay differences related to the vaccination protocols, as well as interassay differences, all assays demonstrated fair performance in predicting the protective effect using the new cutoffs. This study demonstrates the need for a different cutoff for each assay to appropriately determine a higher neutralizing titer and suggests the clinical feasibility of using various assays for estimation of the protective effect.
|Publication status||Published - 2022 Nov|
Bibliographical noteFunding Information:
This study was supported by Boditech Med, Chuncheon, Gangwon-do, South Korea, and SD Biosensor, Suwon, Gyeonggi-do, South Korea, which supplied test kits. However, the sponsors had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work was also supported by a research program funded by the Korea Disease Control and Prevention Agency (number 2021-ER2601-00) and a Samsung Medical Center Grant (number SMO1210321) to J.-H. Ko, and a Seoul National University Bundang Hospital grant (number 14-2021-023) to K.-H. Song. We thank the participants of this study.
© 2022 Lee et al.
All Science Journal Classification (ASJC) codes
- Immunology and Microbiology(all)
- Microbiology (medical)
- Cell Biology
- Infectious Diseases