It’s a pretty simple concept. Covid-19 is transmitted via respiration – breathing out/in…
That means that in order to minimize transmission one has to wear a mask.
Even though we now have vaccines – I’ve been double-vaccinated as of end of February, 2021 – I still will wear a mask until CDC changes the guidelines.
Here’s additional info on wearing masks.
Improving how your masks protect you.
Different types of masks
A Guide to Masks