Antibody Detection in Healthcare Workers after Vaccination with Two Doses of the BNT162b2 or ChAdOx1 Vaccine

Abstract

Background: Due to the COVID-19 pandemic, in 2020, many pharmaceutical companies have developed vaccines. To determine the efficacy of AstraZeneca’s and Pfizer’s vaccines, which were the first and second vaccines to be approved in Korea, respectively, we developed a method to measure their antibody-generating efficacies using immunology analyzers and a rapid antibody test available in Korea. Methods: The antibody-stimulating efficacies of the Pfizer and AstraZeneca vaccines were evaluated using Centaur® XPT SARS-CoV-2 (Siemens Healthineers, Germany), Elecsys® Anti-SARS-CoV-2 S (Roche Diagnostics, Germany), and STANDARD F SARS-CoV-2 nAb FIA (SD Biosensor, Korea). Healthcare workers were enrolled in two groups: the Pfizer (121) and AstraZeneca (117) groups. Antibody levels were measured pre-vaccination, three weeks after vaccination, and 16 weeks after vaccination. Results: The Pfizer group comprised 41 males and 80 females, while the AstraZeneca group comprised 38 males and 79 females. Antibody results were analyzed after excluding four individuals who had recovered from COVID-19. Between weeks 3 and 16, there was no significant difference (P = 0.5, 1.0) between the results of the Roche and Siemens antibody tests in the Pfizer vaccine group. However, the SD Biosensor results of comparing the Roche and Siemens antibody tests at three weeks after the initial vaccination showed a significant difference (P < 0.0001). Analysis of the Roche antibody test results before, at three weeks, and at 16 weeks after the administration of the Pfizer and AstraZeneca vaccines revealed significant differences between before and at three weeks after the first injection (P < 0.0001). Conclusion: After two doses of the Pfizer and AstraZeneca vaccines, antibody formation was above the 90^th percentile of the measurement range in all subjects.