[wbl]

That paper looks at 40 people and has no idea what the clinical correlates of the non-spike responses are because no one has any idea. You cannot take that paper and say that a substantial factor of people are protected due to preexisting responses.

[lbeltrame]

There's at least another paper detailing this phenomenon[1] so for sure it warrants further investigation.

[1] https://www.nature.com/articles/s41590-020-00808-x