Total anti sars cov 2 nucleocapsid antibody assay

We studied 136 subjects who received 3 doses of the Pfizer mRNA vaccine (39 males, 97 females, mean age 43.8 ± 13.5 years) from January 2021 to May 2022. During this period, our country experienced two waves of SARS-CoV-2 variants: Delta from August to November 2021, and Omicron from December 2021 onwards [13 (link)]. All subjects were COVID-19 naïve, with no reported COVID-19 infections during the entire study period, which was evidenced by negative SARS-CoV-2 nucleocapsid antibodies (Roche total anti-SARS-CoV-2 nucleocapsid antibody assay) at the beginning of the study and at all time points tested to account for asymptomatic/pauci-symptomatic infections. Total S-Ab (Roche), IgG S-Ab (Abbott), and neutralizing antibodies (N-Ab) (Snibe) levels were tested at set time points after vaccination up to 210 days post-booster. IgM S-Ab (Abbott) levels were tested up to 60 days post-booster. Due to differences in subject vaccination schedules, the number of samples differed at each time point. All samples obtained in this study were de-identified and anonymized.

We included 32 subjects who received 3 doses of CoronaVac inactivated virus vaccine (mean age of 46.1 ± 13.6 years) and 136 subjects who received 3 doses of BNT162b2 mRNA vaccine (mean age of 43.8 ± 13.5 years) and tested their antibody levels from January 2021 to April 2022. All samples were from healthcare workers who were reportedly healthy, and we had immunocompromised subjects. During this period, Singapore experienced two waves of SARS-CoV-2 variants: Delta (August to November 2021) and Omicron (from December 2021 onwards) [8 (link)]. BNT162b2 vaccinees were COVID-19-naïve throughout the study, as evidenced by negative total SARS-CoV-2 nucleocapsid antibodies (Roche total anti-SARS-CoV-2 nucleocapsid antibody assay) at all time points. As nucleocapsid antibodies also increase after inoculation with inactivated virus vaccines [9 (link)], CoronaVac vaccinees were deemed COVID-19-naïve based on the absence of symptomatic disease throughout the study. Antibodies were tested at set time points up to 90 days post-booster vaccination. The numbers of samples differed at each time point due to variations in vaccination schedules among participants. All samples obtained in this study were de-identified and anonymized.