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. 2022 Dec;11(1):250-259.
doi: 10.1080/22221751.2021.2023328.

A new testing platform using fingerstick blood for quantitative antibody response evaluation after SARS-CoV-2 vaccination

Jinwei Du  1 , Dayu Zhang  1 , Joseph A Pathakamuri  2 , Daniel Kuebler  2 , Ying Yang  1 , Yulia Loginova  1 , Eric Chu  1 , Roberta Madej  1 , Jocelyn V Neves  2 , Brianna Singer  2 , Holly Radke  2 , Naomi Spencer  2 , Elizabeth Rizk  2 , Aiguo Zhang  1 , Chuanyi M Lu  3 , Michael Y Sha  1
Affiliations

A new testing platform using fingerstick blood for quantitative antibody response evaluation after SARS-CoV-2 vaccination

Jinwei Du et al. Emerg Microbes Infect. 2022 Dec.

Abstract

Testing and vaccination have been major components of the strategy for combating the ongoing COVID-19 pandemic. In this study, we have developed a quantitative anti-SARS-CoV-2 spike (S1) IgG antibody assay using a fingerstick dried blood sample. We evaluated the feasibility of using this high-throughput and quantitative anti-SARS-CoV-2 spike (S1) IgG antibody testing assay in vaccinated individuals. Fingerstick blood samples were collected and analyzed from 137 volunteers before and after receiving the Moderna or Pfizer mRNA vaccine. Anti-SARS-CoV-2 S1 IgG antibody could not be detected within the first 7 days after receiving the first vaccine dose, however, the assay reliably detected antibodies from day 14 onwards. In addition, no anti-SARS-CoV-2 nucleocapsid (N) protein IgG antibody was detected in any of the vaccinated or healthy participants, indicating that the anti-SARS-CoV-2 S1 IgG assay is specific for the mRNA vaccine-induced antibodies. The S1 IgG levels detected in fingerstick samples correlated with the levels found in venous blood plasma samples and with the efficacy of venous blood plasma samples in the plaque reduction neutralization test (PRNT). The assay displayed a limit of quantification (LOQ) of 0.59 μg/mL and was found to be linear in the range of 0.51-1000 μg/mL. Finally, its clinical performance displayed a Positive Percent Agreement (PPA) of 100% (95% CI: 0.89-1.00) and a Negative Percent Agreement (NPA) of 100% (95% CI: 0.93-1.00). In summary, the assay described here represents a sensitive, precise, accurate, and simple method for the quantitative detection and monitoring of post-vaccination anti-SARS-CoV-2 spike IgG responses.

Keywords: COVID19; SARS-CoV-2; anti-SARS-CoV-2 igG; fingerstick blood; quantitative immunoassay. SARS-CoV-2 vaccination.

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Conflict of interest statement

No potential conflict of interest was reported by the author(s).

Figures

Figure 1.
Figure 1.
A high-throughput immunoassay platform for anti-SARS-CoV-2 S1 IgG detection using a single drop of fingerstick blood collected in an EDTA tube or on a flocked swab.
Figure 2.
Figure 2.
Standard curve generated by Luminex xPONENT software (R2 = 0.9996). X-axis: IgG concentration (μg/mL); Y-axis: Median Fluorescence Intensity (MFI).
Figure 3.
Figure 3.
Quantitative measurements of anti-SARS-CoV-2 spike IgG before and after receiving the first dose of the Moderna COVID-19 mRNA vaccine. The floating lines and numbers represent the mean values for each sample group. Week 0-1, N = 53; Week 2, N = 38; Week 3, N = 44.
Figure 4.
Figure 4.
SARS-CoV-2 mRNA vaccine-induced humoral immune responses. Shown are the semi-quantitative anti-SARS-CoV-2 S1 IgG antibody levels from 76 vaccinated participants (213 data points). P = 0.198 from Week 0 to Week 12; P < 0.001 after Week 13 using the two-tailed Mann–Whitney U test.
Figure 5.
Figure 5.
Comparison of MFI from fingerstick blood samples collected in EDTA tubes vs those collected on dried swabs. Bivariate Normal Ellipse P = 0.95. Number of samples = 43.
Figure 6.
Figure 6.
Comparison of MFI between venous blood plasma in EDTA tube and fingerstick blood on dried swab. R2 = 0.88, and P-value for the coefficient of dried swab < 0.001. Number of samples  = 31.
Figure 7.
Figure 7.
Microsphere-based anti-SARS-CoV-2 S1 IgG versus PRNT-based neutralizing antibody levels. Linear fit on semi-log plot, R2 = 0.625.
Figure 8.
Figure 8.
Comparison of anti-SARS-CoV-2 S1 IgG and anti-SARS-CoV-2 N protein IgG in vaccinated and previously infected groups. Fingerstick blood sample-based antibody immunoassay using SARS-CoV-2 S1 RBD protein and nucleocapsid (N) protein-coupled microspheres.
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References

    1. WHO Coronavirus (COVID-19) Dashboard. WHO Coronavirus (COVID-19) Dashboard 2021 https://covid19.who.int.
    1. Robbiani DF, et al. . Convergent antibody responses to SARS-CoV-2 in convalescent individuals. Nature. 2020;584:437–442. doi:10.1038/s41586-020-2456-9. - DOI - PMC - PubMed
    1. Wang C, et al. . A human monoclonal antibody blocking SARS-CoV-2 infection. Nat Commun. 2020;11:2251. doi:10.1038/s41467-020-16256-y. - DOI - PMC - PubMed
    1. Zost SJ, et al. . Potently neutralizing and protective human antibodies against SARS-CoV-2. Nature. 2020;584:443–449. - PMC - PubMed
    1. Liu L, et al. . Potent neutralizing antibodies against multiple epitopes on SARSCoV-2 spike. Nature. 2020;584:450–456. - PubMed