“When COVID-19 burst on to the scene, tests quickly showed that everyone was susceptible - no pre-existing antibodies were found that bound to the SARS-CoV-2 virus. This led to dire predictions that over 80% of the population might eventually fall ill. Now more than six months in, this has not happened, and it does not appear to be close to happening.”

This is a well thought out article. Recommended.

https://berthub.eu/articles/posts/covid-19-t-cells/