Detection of SARS-CoV-2 Nucleocapsid, Spike, and Neutralizing Antibodies in Vaccinated Japanese

Abstract

Serological detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N), spike (S), and neutralizing antibodies (Abs) is commonly undertaken to evaluate the efficacy of vaccination. However, the relative efficiency of different SARS-CoV-2 Ab detection systems has not been extensively investigated. Here, we evaluated serological test systems in vaccinated Japanese. SARS-CoV-2 N, S, and neutralizing Abs in sera of 375 healthy subjects a mean 253 days after vaccination were assessed. The sensitivity of Elecsys Anti-SARS-CoV-2 S (Roche S) and Anti-SARS-CoV-2 S IgG (Fujirebio S) was 100% and 98.9%, respectively, with a specificity of 100% for both. The sensitivity of Anti-SARS-CoV-2 neutralizing Ab (MBL Neu) was 2.7%, and the specificity was 100%. Fujirebio S correlated with Roche S (rho = 0.9182, p = 3.97 × 10−152). Fujirebio S (rho = 0.1295, p = 0.0121) and Roche S (rho = 0.1232, p = 0.0170) correlated weakly with MBL Neu. However, Roche S did correlate with MBL Neu in patients with COVID-19 (rho = 0.8299, p = 1.01 × 10−12) and in healthy subjects more recently after vaccination (mean of 90 days, rho = 0.5306, p = 0.0003). Thus, the Fujirebio S and Roche S results were very similar, but neither correlated with neutralizing antibody titers by MBL Neu at a later time after vaccination.

Utility of Roche Elecsys anti-SARS-CoV-2 S in ascertaining post-vaccine neutralizing antibodies

“…Several other studies [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] have also ascertained clinical sensitivity of the assay after exposure to the SARS-CoV-2 virus or vaccine or both, and specificity through evaluation of pre-pandemic specimens. Sensitivities have been reported at time intervals varying from 14 days to 240 days post-exposure.…”

Increasing test specificity without impairing sensitivity: lessons learned from SARS-CoV-2 serology

“…This could be counteracted by increasing sensitivity through modified cut-offs, and specificity would subsequently be restored by a second test. For SARS-CoV-2 testing, it must be further emphasised that different mechanisms of immunisation induce different humoral responses, whereas an infection usually leads to both antinucleocapsid and antispike antibodies, the immune response to an mRNA-based, vector-based or protein-based vaccine that introduces only the spike-protein lacks the anti-nucleocapsid antibody 32. Accordingly, among the vaccinated, tests assessing antispike antibodies might not be useful in detecting individuals after SARS-CoV-2 infection, as the measured amount would have at least partly been induced by the vaccine.…”

“…protein-vaccine that introduces only the spike-protein lacks the anti-nucleocapsid antibody. 32 Accordingly, among the vaccinated, tests assessing antispike antibodies might not be useful in detecting individuals after SARS-CoV-2 infection, as the measured amount would have at least partly been induced by the vaccine. However, add-on infection could boost antispike levels.…”

Associations of HLA Polymorphisms with Anti-SARS-CoV-2 Spike and Neutralizing Antibody Titers in Japanese Rheumatoid Arthritis Patients Vaccinated with BNT162b2

“…It is thought that the long-term production of neutralizing Abs is important for protection against SARS-CoV-2 infection. Humoral responses against COVID-19 mRNA vaccines are quite variable between individuals, influenced inter alia by age, sex, the time between the last vaccination and blood collection, or adverse reactions to the vaccine [ 5 , 6 , 7 ]. Levels of anti-SARS-CoV-2 S and neutralizing Abs were reported to be lower in patients with rheumatic diseases including rheumatoid arthritis (RA) relative to healthy controls [ 8 , 9 , 10 ].…”