Because when she'd go out of the house she never once worried about catching a disease that could kill her. Now she knows and she can't unknow so she split.
Me? I don't trust anyone. Not wear my mask when others are around? Not on your life.
Plus which
Mutations and variants continue to proliferate. Booster shots will be needed. No one knows FOR SURE how long the protection lasts.
We don't know a lot more than we do know.
So good luck to you who have returned the same as you were when you left.
See ya around. I hope.