Immunological Memory to SARS-CoV-2: Microbial Minutes

Jan. 12, 2021

Does exposure to SARS-CoV-2 produce immunological memory? If so, how long do those “memories” last, and what are the implications on the development and longevity of vaccine-induced protection?

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The kinetics of immunological memory to SARS-CoV-2 and the behavior of key immunological players involved in those processes are topics that underpin many of the critical questions that continue to circulate about COVID-19 vaccine development. 

Immune memory is the source of protective immunity against future infection. In a broad sense, the term refers to the immune system’s ability to recognize and mount a successful defense against a specific pathogen. Long-term, comprehensive analyses of the kinetics of the consortium of immune cells involved in this process (including antibodies, B cells, CD8+ T cells and CD4+T cells) is necessary to gain perspective about long-term immunity to SARS-CoV-2. 

Here we dive into the research that seeks to explain how the immune system behaves, as it pertains to this virus. The papers and key take-away points discussed in this Microbial Minutes are listed below.

What is immunological memory?

Addetia A. et al. Neutralizing Antibodies Correlate with Protection from SARS-CoV-2 in Humans during a Fishery Vessel Outbreak with a High Attack Rate. Journal of Clinical Microbiology. Aug. 14, 2020.

Cox R.J. et al. Not just antibodies: B cells and T cells mediate immunity to COVID-19. Nature Reviews Immunology. Aug. 24, 2020.

Sekine T. et al. Robust T Cell Immunity in Convalescent Individuals with Asymptomatic or Mild COVID-19. Cell. Oct. 1, 2020.

Arnold C. Why antobodies may not be the key to beating coronavirus. National Geographic. Aug. 7, 2020.

How long does immunological memory to SARS-CoV-2 last? 

Dan J.M. et al. Immunological memory to SARS-CoV-2 assessed for greater than six months after infection. bioRxiv. Nov. 16, 2020

Take-Away Points

  • Development of protective immunity takes time and depends on complex relationships between multiple cellular components that exhibit distinct kinetics and behavior. 
  • SARS-CoV-2-specific T cells have been detected in the absence of circulating antibodies.
  • Durable immunity against SARS-CoV-2 seems to be a possibility in most individuals, and evidence suggests that these immune responses may persist for 6 months or more post infection. 

Author: Ashley Hagen, M.S.

Ashley Hagen, M.S.
Ashley Hagen, M.S. is the Scientific and Digital Editor for the American Society for Microbiology and host of ASM's Microbial Minutes.