Here we show that in convalescent individuals who had experienced mild SARS-CoV-2 infections ( n = 77), levels of serum anti-SARS-CoV-2 spike protein (S) antibodies declined rapidly in the first 4 months after infection and then more gradually over the following 7 months, remaining detectable at least 11 months after infection. Nonetheless, it has been reported that levels of anti-SARS-CoV-2 serum antibodies decrease rapidly in the first few months after infection, raising concerns that long-lived BMPCs may not be generated and humoral immunity against SARS-CoV-2 may be short-lived 11, 12, 13. Individuals who have recovered from COVID-19 have a substantially lower risk of reinfection with SARS-CoV-2 8, 9, 10.
Long-lived bone marrow plasma cells (BMPCs) are a persistent and essential source of protective antibodies 1, 2, 3, 4, 5, 6, 7.
