Comparison of antibody immune responses between BNT162b2 and mRNA-1273 SARS-CoV-2 vaccines in naive and previously infected individuals

Background Two mRNA vaccines, Pfizer-BNT162b2 and Moderna-mRNA-1273, obtained the Emergency Use Listing by WHO for preventing COVID-19. However, little is known about the difference in antibody responses induced by these two mRNA vaccines in naive and previously infected (PI) individuals. Method We investigated the levels of anti-S-RBD (total, IgG and IgA) levels in naive and PI individuals, 1-13 (median = 6) weeks following the second dose of either vaccine. Results in the naive-vaccinated group, the mRNA-1273 vaccine induced significantly higher levels of anti-S-RBD total antibodies (3.5-fold; P < 0.001), IgG (2-fold, P < 0.01) and IgA (2.1-fold, P < 0.001) as compared with the BNT162b2 vaccine. In addition, both vaccines produced significantly higher anti-S-RBD total antibody levels in the PI-group compared with naive-vaccinated group. The PI group elicited a higher level of anti-S-RBD IgG than the naive-BNT162b2 (P = 0.05), but not more than the naive-mRNA-1273 (P = 0.9) group. Interestingly, the PI vaccinated group elicited a comparable level of IgA ratio to the naive-mRNA-1273 group but significantly higher than the naive-BNT162b2 group (1.6-fold, P < 0.001). Conclusion Our results showed that the PI-vaccinated group produces a higher level of antibodies than the naive vaccinated group, particularly for those vaccinated with BNT162b2.