Pre-existing Immunity to SARS-CoV-2: Implications for the Severity and Vaccine Response of COVID-19¹

More data regarding the detection and characteristics of SARS-CoV-2 T cell responses in humans become available since the outbreak of COVID-19 in December 2019. Since the T cell reactivity against SARS-CoV-2 has been demonstrated in many unexposed individuals, it is speculated that SARS-CoV-2 specific T cells might originate from the memory T cells derived from the exposure to “common cold” corona-virus, which circulate in the human population widely to limit mild respiratory symptoms. Although the clinical relevance remains unclear, the pre-existence of SARS-CoV-2 immune reactivity in the general population could contribute to implications for COVID-19 disease severity, herd immunity and vaccine development.

References

1. Sette A, et al. Nat Rev Immunol. 2020;20:458