The headline gives the impression it was a pure 3 week isolation but.....
Her husband was coming and going even though he stayed in his own room. she went out to get the mail and she brought in food dropped of at the door by a woman (who tested positive).
She was working hard at it but those virus critters are sneaky and always trying to find a way.
When you role the dice you sometimes get snake eyes.
I could see a situation where a person who has covid19 sneezes while walking on an empty street.
The droplets with the virus fall to the pavement, where they can survive for days.
A person takes his dog for a walk and the dog picks up the viruses on his paws.
When they get home the dog gets on the owners lap and transmits the viruses.
The dog owner transmits the virus to his face eyes, mouth etc and gets sick. Never had any direct contact or saw an infected person.
Things happen don't they. -Tom