To better understand this paradox, we enrolled 19 healthy adults at 1.5–33 months after SARS-CoV-2 mRNA vaccine and measured influenza-, tetanus-, or SARS-CoV-2-specific antibody secreting cells (ASC) in LLPC (CD19−) and non-LLPC (CD19+) subsets within the BM. This evidence concerns the gene CD19 and tetanus.