Here is a link from a dependable source:
https://www.webmd.com/lung/coronavir...ssion-overview
The link lists how the disease is or could be transmitted. Remember that some things are not fully known because the virus is new to humans.
As I understand this, masks help keep droplets containing the virus from being propelled into the air and to another person. Masks are worn principally to protect others. Others wear masks to protect you.
When all of this started, I think they did not want the general populace to buy masks because they were needed for medical people. I doubt they imagined that people would sew or make their own.
You know, you can look up how the virus is transmitted.you don’t have to wonder about that. I think there will be new details learned as we go along, but basically how it is spread is known, and available online.