“Abstract: Long-lived bone marrow plasma cells (BMPCs) are a persistent and essential source of protective antibodies^{1,2,3,4,5,6,7}. Individuals who have recovered from COVID-19 have a substantially lower risk of reinfection with SARS-CoV-2^8,9,10    …Consistently, circulating resting memory B cells directed against SARS-CoV-2 S were detected in the convalescent individuals. Overall, our results indicate that mild infection with SARS-CoV-2 induces
robust antigen-specific, long-lived humoral immune memory in humans…”

“Discussion…Overall, our data provide strong evidence that SARS-CoV-2 infection in humans robustly establishes the two arms of humoral immune memory: long-lived BMPCs and memory B cells. These findings provide an immunogenicity benchmark for SARS-CoV-2 vaccines and a foundation for assessing the durability of primary humoral immune responses that are induced in humans after viral infections.”

SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans. Turner, J.S., Kim, W., Kalaidina, E. et al. SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans. Nature 595, 421–425 (2021). https://doi.org/10.1038/s41586-021-03647-4