“What Do We Know About T-Cells and COVID-19 Immunity?” from SciShow, narrated by Hank Green.
The speaker explains that T-cell “immunity” refers to the T-cell response, in directing memory B cells to make antibodies to a virus similar to ones it has seen, and killing infected cells. It does not make one immune to COVID by itself.
He notes a rather disturbing observations: strong T-cell response in females correlates with a worse outcome, but in some men it has resulted in cytokine storms.
However, we’ve noticed that outdoor protesters (who use masks sometimes but shout a lot) don’t seem to be getting severe COVID, and neither do the journalists who cover them (male or female).
And there are numerous reports of severe illness even in young women. What seems to be a common denominator may be size of exposure, in a prolonged indoor event or in a large household.
Wikipedia embed: 3-D rendering of a T-cell, click for attribution