Alva Review-Courier -

A lot of the effort to slow the spread of the coronavirus comes down to a seemingly simple concept: Wearing a mask.

But the issue has proven a thorny one. Health authorities have changed their guidance on who should wear masks and when to wear them. This has led to some confusion and even suspicion.

But since the coronavirus first appeared, authorities have gained a better understanding of how it spreads and how masks can help stop that spread.

Here's a look at how what we know about masks has changed, and how government officials are increasingly getting behind the idea of mandating the use o...