The team will be conducting a larger study of exposed, uninfected subjects to examine whether T cells can protect against COVID-19 infection or alter the course of infection. They will also be exploring the potential therapeutic use of SARS-CoV-2-specific T cells.

https://scitechdaily.com/scientists-uncover-evidence-that-a-level-of-pre-existing-covid-19-sars-cov-2-immunity-is-present-in-the-general-population/

From 7/2020 - seems a good time to repost for those just waking up