If the body produces any (even low count of) T-cells, that's enough to definitively overcome any reasonable degree of a COVID infection?
Nobody knows yet. Could be that it's enough to prevent the virus from reproducing at all, so the person doesn't get sick, or perhaps enough to slow the virus down, so the illness is milder.
Maybe some T-cells are a normal immune reaction and unless the person has immunity from an infection or vaccine it's fake news and meaningless.
The T-cells they're referring to in the article are specific to the coronavirus, and these would not normally be found in the blood of someone who has not been infected with that virus, or a closely related one.
More on specificity and cross-reactivity.Like, what does "may be immunity" even mean?
I think what was intended was "These people (the 35% who had T-cells that reacted with the current virus despite no exposure to the virus) may be immune to further infection with the current virus."