This article examines the durability of B and T cell immunity throughout 2021 from the Alpha to the Omicron variants. “T cell responses to early variants were preserved across vaccine platforms. By contrast, significant overall decreases were observed for memory B cells and neutralizing antibodies.”
In subjects ∼6 months post-vaccination, 90% (CD4+) and 87% (CD8+) of memory T cell responses were preserved against variants and 84% (CD4+) and 85% (CD8+) preserved against Omicron.
Omicron RBD memory B cell recognition was substantially reduced to 42% compared to other variants. T cell epitope repertoire analysis revealed a median of 11 and 10 spike epitopes recognized by CD4+ and CD8+ T cells, with average preservation > 80% for Omicron.
Functional preservation of the majority of T cell responses may play an important role as second-level defenses against diverse variants.