Study tracks COVID-19 antibodies over time

Date:
April 14, 2022
Source:
University of Virginia Health System
Summary:
A new study of COVID-19 antibodies shows that Pfizer vaccine
antibodies fall faster than Moderna -- and for Pfizer recipients,
age matters.



FULL STORY ==========================================================================
The antibodies generated by Pfizer's COVID-19 vaccine rise more slowly
and decline more quickly than those generated by the Moderna vaccine,
according to a new study from UVA Health. The study also finds that
older recipients of the Pfizer vaccine generated fewer antibodies than
did younger recipients -- but this wasn't the case for Moderna, where
age did not appear to be a factor.


==========================================================================
The researchers determined that both vaccines generated similar peak
levels of COVID-fighting antibodies. This result is at odds with a
prior report from the same group that showed antibodies were higher
after Moderna, but they say the discrepancy likely can be explained
by the faster rate at which the Pfizer antibodies decline. It will be
important for future research to consider time frame from vaccination
carefully when assessing peak antibody response, they say.

"It is not surprising that antibody levels fall after vaccination," said
Behnam Keshavarz PhD, an immunologist at the University of Virginia School
of Medicine. "But we were struck by how rapidly the antibodies fell after
the mRNA vaccines, particularly the Pfizer/BioNTech vaccine." Tracking
the COVID-19 Vaccines Keshavarz and colleagues tracked post-vaccination antibody levels in 234 UVA employees over 10 months. In total, 114 had
received Pfizer's vaccine and 114 had received Moderna's, while six had received Johnson & Johnson's single shot.

A week to 20 days after their second dose, recipients of Pfizer's and
Moderna's mRNA vaccines had antibody levels that were approximately
50 times higher those seen in the J&J recipients. Shortly thereafter
antibodies from both Pfizer and Moderna began to drop, but the drop was
more precipitous for Pfizer.



========================================================================== After six months, Pfizer vaccine recipients had antibody levels lower
than both the Moderna recipients and patients who had been hospitalized
with severe COVID-19 six months prior. (Patients who suffer severe COVID
are thought to generate more antibodies than people who recover from
mild cases.) The scientists note that while the Pfizer and Moderna
vaccines are similar, there are differences in their formulations and
the amount of mRNA they contain. This could explain the differences in
antibody response they generate.

Time between doses also could be a significant factor.

It's important to understand that antibody levels are a relatively
crude tool to assess vaccine effectiveness; doctors aren't even
sure there's a direct correlation between antibody level and COVID-19 protection. Antibody levels naturally decline, whether after vaccination
or illness, but the immune system remembers how to make the necessary antibodies when again confronted by the virus. Time has already told
the most important story: All three vaccines examined in UVA's study
have performed remarkably well in protecting against severe illness, hospitalization and death.

Understanding how antibody levels decline, however, may help doctors
and policymakers gauge when booster shots are needed, and who should
receive them.

For example, the study found that older recipients of Pfizer's vaccine generated fewer antibodies than did younger recipients. This was true in
the first three weeks and confirmed four to six months later. But this
wasn't the case for Moderna recipients -- age didn't appear to have a significant effect.

This raises the possibility that booster shots may be of more benefit
to older Pfizer recipients than to older Moderna recipients, though this
idea would need more study.

The researchers also noticed that there was a trend for men to generate
fewer antibodies than did women, but, contrary to a prior report, this
was ultimately deemed statistically insignificant.



==========================================================================
The scientists note that it remains unclear if the greater antibody
response generated by the Moderna vaccine translates into better
real-world protection.

But the study, they say, may help explain emerging differences in COVID-19 infection rates seen among recipients of the different vaccines.

"Both Pfizer/BioNTech and Moderna have proven very effective in protecting against severe disease, but our study builds on others that have shown
some subtle differences in outcomes that favor Moderna," said senior
author Jeffrey Wilson, MD, PhD. "This could particularly be true in higher
risk populations, such as older subjects or those who have conditions
with suppressed immune systems." Findings Published The researchers
have published their findings in the scientific journalFrontiers in
Immunology. The research team consisted of Behnam Keshavarz, Nathan
E. Richards, Lisa J. Workman, Jaimin Patel, Lyndsey M.

Muehling, Glenda Canderan, Deborah D. Murphy, Savannah G. Brovero,
Samuel M.

Ailsworth, Will H. Eschenbacher, Emily C. McGowan, Barbara J. Mann,
Michael R.

Nelson, Alexandra Kadl, Judith A. Woodfolk, Thomas A.E. Platts-Mills
and Jeffrey M. Wilson. Platts-Mills and Wilson disclosed that they
have received assay support from Thermo-Fisher/Phadia unrelated to
the study. Wilson also has received consultancy fees from the company
unrelated to the research.

The work was supported by UVA's Manning COVID-19 Research Fund, a UVA
School of Medicine GAP Award, an American Academy of Allergy, Asthma and Immunology Faculty Development Award and National Institutes of Health
grants R37-AI20565 and R21-AI160334.


========================================================================== Story Source: Materials provided by
University_of_Virginia_Health_System. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Behnam Keshavarz, Nathan E. Richards, Lisa J. Workman, Jaimin Patel,
Lyndsey M. Muehling, Glenda Canderan, Deborah D. Murphy, Savannah G.

Brovero, Samuel M. Ailsworth, Will H. Eschenbacher, Emily
C. McGowan, Barbara J. Mann, Michael R. Nelson, Alexandra
Kadl, Judith A. Woodfolk, Thomas A.E. Platts-Mills, Jeffrey
M. Wilson. Trajectory of IgG to SARS- CoV-2 After Vaccination
With BNT162b2 or mRNA-1273 in an Employee Cohort and Comparison
With Natural Infection. Frontiers in Immunology, 2022; 13 DOI:
10.3389/fimmu.2022.850987 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220414110724.htm

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