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

Al-Sadeq, D.; Shurrab, F.; Ismail, A.; Amanullah, F. H.; Thomas, S.; Aldewik, N.; Yassine, H. M.; Abdul Rahim, H.; Abu-Raddad, L. J.; Nasrallah, G.

Two mRNA vaccines, Pfizer-BNT162b2 and Moderna-mRNA-1273, were granted the US Food and Drug Administration Emergency Use Authorization for preventing COVID-19. However, little is known about the difference in antibody responses induced by the two mRNA vaccines in naive and individuals with a previous history of infections (PI group). Therefore, we investigated the levels of anti-S-RBD total antibodies (IgM, IgA, and IgG), anti-S-RBD IgG, and anti-S-RBD IgA in these two groups 1-13 (median=6) weeks following administration of two doses of mRNA-1273 or BNT162b2 vaccines. Results showed that in naive-vaccinated group, the mRNA-1327 vaccine induces significantly higher levels of S-RBD total antibodies (3.5-fold; p<0.001), S-RBD IgG (2-fold-p<0.01), and S-IgA (2.1-fold, p<0.001) than the BNT162b2 vaccine. In the PI-vaccinated group, both vaccines produce significantly higher S-RBD total antibodies level than those of the naive-vaccinated group. The PI group produced a higher level of 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 produced 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). Our results showed that the mRNA-1327 vaccine is more immunogenic and induces a greater antibody response than the BNT162b2 vaccine.