Summary Background BNT162b2 (Pfizer/BioNTech, Comirnaty) and mRNA-1273 (Moderna, Spikevax) are messenger RNA (mRNA) vaccines that elicit antibodies against the spike receptor-binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). ) (S-RBD) and have been approved by the US Food and Drug Administration to combat the coronavirus disease 2019 (COVID-19) pandemic. Because vaccine efficacy and antibody levels decreased over time after the primary 2-shot series, the U.S. Food and Drug Administration authorized a booster (third) dose for both mRNA vaccines. for adults in fall 2021. Aim To evaluate the magnitude and durability of immunoglobulin (Ig)G S-RBD after the mRNA vaccine booster dose compared to the primary series. We also compared S-RBD IgG levels after BNT162b2 and mRNA-1273 boosts and explored the effects of age and previous infection. Methods Around receipt of the second and third homologous doses of the mRNA vaccine, adults in an employee-based cohort provided serum and completed questionnaires, including information about previous COVID-19 infections. IgG to S-RBD was measured using an ImmunoCAP-based system. A subset of samples was tested for IgG against SARS-CoV-2 nucleocapsid using a commercial assay. Results There were 228 subjects who had samples collected between 7 and 150 days after their primary series vaccination and 117 subjects who had samples collected in the same time period after their booster. Antibody levels 7 to 31 days after the primary and booster series were similar, but S-RBD IgG was longer lasting over time after the booster, regardless of prior infection status. Furthermore, mRNA-1273 post-boost antibody levels exceeded BNT162b2 at 5 months. Conclusion COVID-19 mRNA vaccine boosters increase antibody durability, suggesting greater long-term clinical protection against SARS-CoV-2 infection compared to the 2-shot regimen. |
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New research from the University of Virginia School of Medicine talks about the benefits of a COVID-19 booster.
The new findings shed light on how the mRNA boosters, from both Pfizer and Moderna, affect the durability of our COVID-19 antibodies. A booster, the researchers report, produced longer-lasting antibodies for all recipients, even those who have recovered from a COVID-19 infection.
"These results are consistent with other recent reports and indicate that booster vaccines improve the durability of antibodies elicited by the vaccine," said lead investigator Jeffrey Wilson, MD, PhD, of the Division of Asthma, Allergy and Immunology at UVA Health. .
COVID-19 Antibody Tracking
Wilson and his colleagues looked at antibody levels after a booster in 117 UVA employee volunteers and compared those results to the levels seen in 228 volunteers after their primary vaccination series. Antibody levels from one week to 31 days after the primary and booster series were similar, but boosted antibodies persisted longer regardless of whether the person had had COVID-19.
“Our initial thought was that boosters would lead to higher antibody levels than the primary vaccine series, but that’s not what we found,” said researcher Samuel Ailsworth, the first author of a new scientific paper describing the findings. "Instead, we found that the booster led to longer-lasting antibodies."
Antibody levels naturally decrease over time after an infection or after a vaccination, but higher levels are thought to be more protective. Longer-lasting antibodies would therefore be expected to provide more sustained immunity against severe COVID-19.
The researchers found that the antibodies generated by the Moderna booster were longer lasting than those generated by the Pfizer booster. Moderna’s antibody levels exceeded Pfizer’s for five months, at the end of the study period. Although the findings were statistically significant, Wilson notes that both mRNA vaccine boosters provide improved and fairly similar levels of protection against COVID-19 in recently published large epidemiological studies.
Because the frequency of COVID-19 infections in the community was relatively high when the boosters were administered, the authors also studied the effect of COVID-19 infection on antibody levels. The findings suggest that the "increased antibody durability observed after booster vaccination is 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 COVID-19 vaccines over time. Researchers previously found that after the primary vaccination series, antibodies generated by the Pfizer COVID-19 vaccine increased more slowly and decreased more rapidly than those generated by the Moderna vaccine. That study also found that older recipients of the Pfizer vaccine generated fewer antibodies than younger recipients, but this was not 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 older recipients, but this difference disappeared over time.
Wilson notes that this study adds to the accumulating evidence that boosters are important in protecting the community from COVID-19. "Although only about half of the US population who are eligible for a booster have received one, it is increasingly clear that boosters improve the protection conferred by the primary series mRNA vaccines alone," he said. she.
