日本のコウモリから新型コロナウイルスと遺伝的に近縁なウイルスを検出
https://www.a.u-tokyo.ac.jp/topics/topics_20201104-2.html

Older adults lack SARS CoV-2 cross-reactive T lymphocytes
directed to human coronaviruses OC43 and NL63
https://www.nature.com/articles/s41598-020-78506-9
Pre-existing T cell-mediated cross-reactivity to SARS-CoV-2 cannot solely
be explained by prior exposure to endemic human coronaviruses
https://www.biorxiv.org/content/10.1101/2020.12.08.415703v1