Frontiers in Immunology (Feb 2023)

Long-term adaptive response in COVID-19 vaccine recipients and the effect of a booster dose

  • Luca Perico,
  • Marta Todeschini,
  • Federica Casiraghi,
  • Marilena Mister,
  • Anna Pezzotta,
  • Tobia Peracchi,
  • Susanna Tomasoni,
  • Piera Trionfini,
  • Ariela Benigni,
  • Giuseppe Remuzzi

DOI
https://doi.org/10.3389/fimmu.2023.1123158
Journal volume & issue
Vol. 14

Abstract

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We examined the immune response in subjects previously infected with SARS-CoV2 and infection-naïve 9 months after primary 2-dose COVID-19 mRNA vaccination and 3 months after the booster dose in a longitudinal cohort of healthcare workers. Nine months after primary vaccination, previously infected subjects exhibited higher residual antibody levels, with significant neutralizing activity against distinct variants compared to infection-naïve subjects. The higher humoral response was associated with higher levels of receptor binding domain (RBD)-specific IgG+ and IgA+ memory B cells. The booster dose increased neither neutralizing activity, nor the B and T cell frequencies. Conversely, infection-naïve subjects needed the booster to achieve comparable levels of neutralizing antibodies as those found in previously infected subjects after primary vaccination. The neutralizing titer correlated with anti-RBD IFNγ producing T cells, in the face of sustained B cell response. Notably, pre-pandemic samples showed high Omicron cross-reactivity. These data show the importance of the booster dose in reinforcing immunological memory and increasing circulating antibodies in infection-naïve subjects.

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