Antibody Responses to the BNT162b2 mRNA Vaccine in Healthcare Workers in a General Hospital in Japan: A Comparison of Two Assays for Anti-spike Protein Immunoglobulin G

Abstract

Objective This study assessed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses to the BNT162b2 mRNA vaccine in Japanese healthcare workers. Methods In this prospective cohort study, participants received two doses of the BNT162b2 mRNA vaccine on days 0 and 21 and provided blood for anti-SARS-CoV-2 antibody testing before the first vaccine and on days 21 and 35 after vaccination. Anti-spike protein immunoglobulin G (S-IgG) was measured using Abbott and Fujirebio chemiluminescent immunoassays. Participants One hundred healthcare workers (median age: 39 years old, interquartile range: 30-48 years old), including 6 who had been previously infected with SARS-CoV-2 and 3 individuals taking immunosuppressive drugs, participated in the study. ResultsThe S-IgG antibody titers (AU/mL) measured using both the Abbott and Fujirebio assays increased significantly (p<0.001) over time, both with a prevalence of 100% at 35 days after the first vaccination. The multivariate log-normal linear regression analysis indicated the effect of immunosuppressant medication using both the Abbott (p=0.013) and Fujirebio (p=0.039) assays on S-IgG levels after complete vaccination. Pearson's correlation coefficient between the Abbott and Fujirebio S-IgG results in all 300 samples collected before and after vaccination and 50 positive controls from patients with coronavirus disease 2019 were 0.963 [95% confidence interval (CI): 0.954-0.970, p<0.001] and 0.909 (95% CI: 0.845-0.948, p<0.001), respectively. Conclusion The BNT162b2 mRNA vaccine was effective at increasing S-IgG levels in Japanese immunocompetent healthcare workers. The Fujirebio S-IgG assay showed high diagnostic accuracy, using the Abbott S-IgG assay as the reference test.

Head-to-Head Comparison of 5 Anti-SARS-CoV-2 Assays Performance in One Hundred COVID-19 Vaccinees, over an 8-Month Course

“…The results obtained using the investigated methods correlated strongly ( Figure 2 ). The correlation between the immunoassays was previously reported by other researchers [ 31 , 32 , 33 , 34 ]; however, the strength of correlation varies between the papers, which may be attributed to the different timepoints investigated, the samples’ dilutions, and conversion to BAU/mL. Three of the methods included in our study were also compared by Lukaszuk et al in a similar group of vaccinees.…”

Humoral response against spike protein enhanced by fifth and sixth COVID-19 mRNA vaccine in the uninfected and infected subjects

“…S-IgG titers were measured by the CLEIA method using Lumipulse in this study. A few studies were comparing the antibody titers measured by Lumipulse and other automated methods, 23 and also, it is not clear whether the antibodies have direct neutralizing activity against mutant strains, including the Omicron strain. It was reported that the neutralizing antibody titers and IgG antibody titers correlate.…”

Good Immunogenicity of Delayed Second Dose of BNT162b2 Vaccine in Individuals with Acute Allergic-like Reactions after the First Dose

“…The serum samples were stored at −35 • C and tested for SARS-CoV-2 antispike (S) IgG using a commercial chemiluminescence enzyme immunoassay (SARS-CoV-2 S-IgG reagents, Fujirebio, Tokyo, Japan). This test had a specificity of 100 and a 98.7% concordance with the Abbott SARS-CoV-2 S-IgG assay (Abbott Japan LLC, Tokyo, Japan) [8]. If COVID-19 infection was suspected during the study period, participants were tested for SARS-CoV-2 via nasopharyngeal swab samples using a polymerase chain reaction test (ID NOW COVID-19, Abbott Japan LLC) [8].…”