Small enemy, big impact
As published, the average size of the COVID-19 virus is (0.125 micron). One micron is “one millionth of a meter” or (0.000039 inch). Since the average virus is 0.125 micron, or one eight of a micron, that puts its average size at (0.0000049 inch).
We’re all familiar with the width of a dime, published as (0.705 inch). If you were to lay these viruses in a straight line, end to end across the width of a dime, you could lay (143,256) of them across its width.
That’s the size of the enemy you’re fighting and trying to keep from ingesting. Is it any wonder it spreads like wildfire?