I don't know, I'm not a scientist, but this is what we've been told so I'm following what's being said. We've asked the public to wipe down doorknobs, stairwells and mailboxes and possibly leave their packages outside for an extra day to ensure there's no possible tracing of COVID within any kind of package they receive at their home.
Even if you go grocery shopping or go to any store, this should be done as well. Anything that comes into your home from outside should be wiped down to be extra careful, because we cannot guarantee that COVID cannot be transmitted from anywhere.