Alva Review-Courier -

One of the great mysteries of the coronavirus is how quickly it rocketed around the world.

It first flared in central China and, within three months, was on every continent but Antarctica, shutting down daily life for millions. Behind the rapid spread was something that initially caught scientists off guard, baffled health authorities and undermined early containment efforts — the virus could be spread by seemingly healthy people.

As workers return to offices, children prepare to return to schools and those desperate for normalcy again visit malls and restaurants, the emerging science points t...