The BBC had an interesting article on the "hidden protection from COVID19" from T-cell "immunity": https://www.bbc.com/future/article/20200716-the-people-with-

The BBC had an interesting article on the "hidden protection from COVID19" from T-cell "immunity": https://www.bbc.com/future/article/20200716-the-people-with-hidden-protection-from-covid-19 https://www.bbc.com/future/article/20200716-the-people-with-... The article references this paper: https://www.cell.com/cell/pdf/S0092-8674(20)30610-3.pdf https://www.cell.com/cell/pdf/S0092-8674(20)30610-3.pdf "Importantly, we detected SARS-CoV-2-reactive CD4+ T cells in 40%–60% of unexposed individuals, suggesting cross-reactive T cell recognition between circulating ‘‘common cold’’ coronaviruses and SARS-CoV-2."