Both the Pfizer and Moderna vaccines provide very good protection against becoming infected with the SARS CoV2 virus and terrific protection against becoming hospitalized or dying from an infection.
That said, in the last few weeks, a couple of studies have been released showing that the Moderna vaccine elicits a more robust antibody response when compared with the Pfizer vaccine. It’s still unclear whether this will be validated by future research and/or whether any differences in immunity that the vaccines elicit and/or whether if there is a difference, whether it will turn out to be clinically significant. Here are a couple of those studies:
Comparison of SARS-CoV-2 Antibody Response Following Vaccination With BNT162b2 and mRNA-1273
Both the Pfizer and Moderna vaccines provide great protection against COVID infections and terrific protection against needing to be hospitalized or dying of COVID. This serology study shows that the antibody titer response to the Moderna vaccine is significantly higher than that achieved with Pfizer.
Two reasons for that include the higher mRNA content in the Moderna product and the extra week interval in the Moderna administration protocol. It’s still unclear whether this difference is or will be clinically important (e.g. will Moderna provide longer-lasting protection) but it’s plausible.
“Higher antibody titers were observed in participants vaccinated with 2 doses of mRNA-1273 compared with those vaccinated with BNT162b2 (geometric mean titer [GMT], 3836 U/mL [95% CI, 3586-4104] vs 1444 U/mL [95% CI, 1350-1544]; P < .001) (Figure, A).
This study demonstrated a significantly higher humoral immunogenicity of the SARS-CoV-2 mRNA-1273 vaccine (Moderna) compared with the BNT162b2 vaccine (Pfizer-BioNTech), in infected as well as uninfected participants, and across age categories.”
The higher mRNA content in mRNA-1273 compared with BNT162b2 and the longer interval between priming and boosting for mRNA-12733 (4 weeks vs 3 weeks for BNT162b2) might explain this difference.
A relationship between neutralization level after SARS-CoV-2 vaccination and protection against COVID-19 has been demonstrated by several studies.4 As such, the height of the humoral response after vaccination, which correlates with neutralizing antibody titers,5 might be clinically relevant.”
Comparison of SARS-CoV-2 Antibody Response by Age Among Recipients of the BNT162b2 vs the mRNA-1273 Vaccine
This cohort study found that the Pfizer vaccine elicited relatively lower antibody levels in older adults when compared to younger adults. There was no difference in antibody levels between older and younger adults who received Moderna.
One explanation for the difference could be the difference in the amount of mRNA used in the respective vaccines. Pfizer uses 30 μg of MRNA while Moderna uses 100 μg.
