Jeffrey M. Wilson MD Assistant Professor of Medicine Allergy and Immunology University of Virginia

COVID-19: Subtle Differences in Immune Response to Pfizer vs Moderna Vaccines Interview with:

Jeffrey M. Wilson MD Assistant Professor of Medicine Allergy and Immunology University of Virginia

Dr. Wilson

Jeffrey M. Wilson MD
Assistant Professor of Medicine
Allergy and Immunology
University of Virginia What is the background for this study? What are the main findings?

Response: To date there have been few head-to-head studies evaluating the immune responses to COVID-19 vaccines. Here we measured IgG antibodies to the SARS-CoV-2 spike-RBD in adults who received full vaccination with either the Pfizer/BioNTech or Moderna vaccine. Our study is distinguished from many others because we developed a quantitative test with a read-out in standardized units (expressed as micrograms/mL).

We found that antibody levels to the SARS-CoV-2 spike receptor-binding domain were lower in recipients of the Pfizer/BioNTech than Moderna vaccine. The difference in the antibody levels between vaccines was most evident in relatively older subjects. What should readers take away from your report?

Response: The Pfizer/BioNTech and Moderna COVID-19 vaccines are both mRNA-based and have shown strong protection against clinical disease, but our study builds on other recent reports that suggest there could be subtle differences in the immune response elicited by the two vaccines. Whether this translates to differences in protection against the virus is not clear and would require more investigation. What recommendations do you have for future research as a result of this work?

Response: The immune response to viruses is complex and involves a number of elements of the immune system in addition to antibodies. A major question in the field is whether antibody levels correlate with clinical protection against COVID-19. Identification of an antibody cut-off level that predicted protection against COVID-19 would be helpful for monitoring immune responses over time and determining when booster shots would be indicated. Is there anything else you would like to add?

Response: This study represents a small piece of a big puzzle. Despite the differences we found in antibody levels between Pfizer/BioNTech and Moderna we would not hesitate to recommend either vaccine for our patients.  Our group has received research support from Thermo-Fisher/Phadia for work we do in the study of allergic disease, but the company had no role in this study.


Richards NE, Keshavarz B, Workman LJ, Nelson MR, Platts-Mills TAE, Wilson JM. Comparison of SARS-CoV-2 Antibody Response by Age Among Recipients of the BNT162b2 vs the mRNA-1273 Vaccine. JAMA Netw Open. 2021;4(9):e2124331. doi:10.1001/jamanetworkopen.2021.24331

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Last Updated on September 3, 2021 by Marie Benz MD FAAD