Cross-reactive memory T cells and herd immunity to SARS-CoV-2

Nat Rev Immunol. 2020 Nov;20(11):709-713. doi: 10.1038/s41577-020-00460-4. Epub 2020 Oct 6.

Abstract

Immunity is a multifaceted phenomenon. For T cell-mediated memory responses to SARS-CoV-2, it is relevant to consider their impact both on COVID-19 disease severity and on viral spread in a population. Here, we reflect on the immunological and epidemiological aspects and implications of pre-existing cross-reactive immune memory to SARS-CoV-2, which largely originates from previous exposure to circulating common cold coronaviruses. We propose four immunological scenarios for the impact of cross-reactive CD4+ memory T cells on COVID-19 severity and viral transmission. For each scenario, we discuss its implications for the dynamics of herd immunity and on projections of the global impact of SARS-CoV-2 on the human population, and assess its plausibility. In sum, we argue that key potential impacts of cross-reactive T cell memory are already incorporated into epidemiological models based on data of transmission dynamics, particularly with regard to their implications for herd immunity. The implications of immunological processes on other aspects of SARS-CoV-2 epidemiology are worthy of future study.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptive Immunity / drug effects
  • Antibodies, Viral / biosynthesis*
  • Betacoronavirus / drug effects
  • Betacoronavirus / immunology*
  • Betacoronavirus / pathogenicity
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / virology
  • Coronaviridae / drug effects
  • Coronaviridae / immunology
  • Coronaviridae Infections / epidemiology
  • Coronaviridae Infections / immunology
  • Coronaviridae Infections / prevention & control*
  • Coronaviridae Infections / virology
  • Coronavirus Infections / epidemiology
  • Coronavirus Infections / immunology
  • Coronavirus Infections / prevention & control*
  • Coronavirus Infections / virology
  • Cross Reactions
  • Humans
  • Immunity, Herd / drug effects
  • Immunologic Memory
  • Pandemics / prevention & control*
  • Pneumonia, Viral / epidemiology
  • Pneumonia, Viral / immunology
  • Pneumonia, Viral / prevention & control*
  • Pneumonia, Viral / virology
  • Rhinovirus / drug effects
  • Rhinovirus / immunology
  • Viral Vaccines / administration & dosage
  • Viral Vaccines / biosynthesis
  • Viral Vaccines / immunology*

Substances

  • Antibodies, Viral
  • COVID-19 vaccine
  • Viral Vaccines

Supplementary concepts

  • COVID-19
  • severe acute respiratory syndrome coronavirus 2