Nobody knows for sure but I'm addicted to news and remember this well. A bigshot at CDC was working out the guidelines at home and his 14 yo daughter doing homework they started talking about science. He asked her what might be a safe distance in school...3 feet.....5 feet.....10 feet? And she said 6 feet not too close and not too far. He liked the answer and went with it.
I remember telling this story back then and of course nobody believed me....but then too nobody believed me about lockdowns either.
Your heart has an electromagnetic field that extends 6 feet around you. It allows you to connect with anothets electromagnetic field. It harmonizes empathy and allows one to FEEL anothers pain and emotions, if you actually pay attention. That's what they don't want. A lot of open hearts with empathy. Look it up.