A major COVID breakthrough?

Pandemic-wise, things get curiouser and curiouser, as Mark Twain might say. And one particular curiosity could be huge news.

The latest on COVID-19 is that it might not be a new virus after all! 40% of people who get it never develop symptoms (which is why masks help; it's being spread by people who don't know that they have it!). But now, it seems that six different studies have found T-cells that recognize COVID-19 in blood samples that were drawn before COVID-19 was even a thing!

It could be that nearly half of us have been exposed to it (or to a similar enough virus that our immune systems respond to it) somehow in the past and have partial immunity! How in the world this is even possible confuses the living daylights out of the scientists who are working with COVID, but the facts seem to bear it out.

And another possibly major development: there is evidence that having had a recent cold may help protect against the worst effects of the virus. That at least makes some sense; though Rush Limbaugh thoroughly (and stupidly) confused the facts early in the pandemic by making the ridiculous claim that COVID and the common cold were caused by the same virus, it's true that one of the viruses that cause the common cold is a coronavirus (just not COVID-19!). But it's possible that the two could be related closely enough that recent exposure to one could create an immune response of some kind to the other.

Remember, this is only one of several viruses that cause the common cold, so not all colds would have that effect. But one of the more common cold viruses seems to! Could those who have been exposed to that particular virus in the not-too-distant past be the ones who show no symptoms, or few of them, when exposed to SARS-CoV-2?

Might that virus, or one like it, be to COVID-19 what cowpox was to smallpox, at least to a point?