COVID-19 booster increases durability of antibody response
University of Virginia Health System
The new findings shed light on how mRNA
boosters -- both Pfizer and Moderna -- affect the durability of our antibodies
to COVID-19. A booster, the researchers report, made for longer-lasting
antibodies for all recipients, even those who have recovered from a COVID-19
infection.
"These results fit with other recent reports and indicate that booster shots enhance the durability of vaccine-elicited antibodies," said senior researcher Jeffrey Wilson, MD, PhD, of UVA Health's Division of Asthma, Allergy and Immunology.
Tracking COVID-19 antibodies
Wilson and his collaborators looked at
antibody levels following a booster in 117 UVA employee volunteers and compared
those results with the levels seen in 228 volunteers after their primary
vaccination series. Antibody levels one week to 31 days after the primary
series and booster were similar, but the boosted antibodies stuck around longer
regardless of whether the person had had COVID-19.
"Our initial thought was that that
boosters would lead to higher antibody levels than the primary vaccine series,
but that was not what we found," said researcher Samuel Ailsworth, the
first author of a new scientific paper outlining the findings. "Instead,
we found that the booster led to longer lasting antibodies."
Antibody levels naturally decline over time
after an infection or after vaccination, but higher levels are thought to be
more protective. Thus, longer-lasting antibodies would be expected to provide
more sustained immunity against severe COVID-19.
The researchers found that the antibodies
generated by the Moderna booster proved longer lasting than those generated by
the Pfizer booster. Moderna's antibody levels exceeded Pfizer's out to five
months, the end of the study period. Although the findings were statistically
significant, Wilson notes that both mRNA vaccine boosters provide enhanced and
fairly similar levels of protection against COVID-19 in recently published
large epidemiologic studies.
Because the frequency of COVID-19 infections
in the community was relatively high when the boosters were being given, the
authors also studied the effect of COVID-19 infection on antibody levels. The
findings suggest that the "enhanced antibody durability observed after
booster vaccination was not explained by hybrid immunity," the researchers
report in their paper.
The new results are the latest from Wilson's
team tracking the antibody response to the COVID-19 vaccines over time. The
researchers previously found that after the primary vaccination series the
antibodies generated by Pfizer's COVID-19 vaccine rose more slowly and declined
more quickly than those generated by the Moderna vaccine. That study also found
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.
In the latest results, younger booster
recipients initially generated more antibodies than did older recipients, but
this difference disappeared with time.
Wilson notes that this study adds to the
accumulating evidence that boosters are an important of protecting the
community from COVID-19. "Although only about half of the U.S. population
that is eligible for a booster has received one, it is increasingly clear that
boosters enhance the protection that is conferred by the primary series mRNA
vaccines alone," he said.
Findings Published
The researchers have published their latest
findings in the scientific journal Annals of Allergy, Asthma &
Immunology. The team consisted of Samuel M. Ailsworth, Behnam Keshavarz,
Nathan E. Richards, Lisa J. Workman, Deborah D. Murphy, Michael R. Nelson,
Thomas A.E. Platts-Mills and Wilson. The researchers reported no financial
interests in the work.
The research was supported by the UVA Manning COVID-19 Research Fund, an American Academy of Allergy, Asthma & Immunology Faculty Development Award and National Institutes of Health grant R37-AI20565.
