Research on Lasting Immunity to SARS-CoV-2
June 1, 2021
New research published in Nature has shown that immunity to SARS-CoV-2 can last from one year to possibly a lifetime, as a “SARS-CoV-2 infection induces a robust antigen-specific, long-lived humoral immune response in humans.”
The research, conducted at Washington University in St. Louis, studied participants who had been previously infected with COVID-19. Blood samples from 77 participants who experienced mild Covid infection were studied at three-month intervals starting at one month post-infection. Antibody levels declined sharply during the first four months and then steadily thereafter, and remained detectable at least 11 months post-infection. Bone marrow samples were also taken from 18 participants 7-8 months after infection, 15 of which exhibited memory B cells.
“Bone marrow plasma cells are a persistent and essential source of protective antibodies,” and memory B cells contained in the bone marrow remain dormant and ready to produce antibodies in case of re-exposure to the virus. This may even include variants.
Immune memory after fighting a live virus from natural infection is different to vaccine immunity, in which the body is exposed to a deconstructed viral protein. Those immunized 6-12 months post-Covid-infection may have a different immune response than those who have not experienced infection and get immunized. Thus, boosters are not necessary for those previously infected with COVID-19 who have also been inoculated with a full dose of the vaccine. To learn more about how each dose of the mRNA vaccine produces separate antibody responses, check out our article.