twitterlit prompt : It only takes one thing to kill you

She’d lived a very isolated, insulated sort of life. There was never a time she was allowed out without a hat. If it was cold she always had a scarf and a jacket. Her mother insisted she always use an umbrella. In winter the covers were always three thick on the bed and even on the warmest summer evenings Mother came in and shut the window so there would not be a draft.
It was the time and she understood, with so many children dying from polio one couldn’t be too careful. There was never dirt under her fingers. Of course that would require actually having played with something dirty and that never ever happened.
The house always had a very antiseptic smell to it. It was always quiet but not exactly peaceful, though Margaret made her own little world with her dolls and her books and her colors. They rarely had visitors. It was such a chore to scrub everything afterward to make certain that all the germs were dead.
Mother was very careful to prepare all the food so that there were no germs, or dirt or anything that could make them sick. Margaret wondered if food tasted different if you didn’t boil it.
She was homeschooled and so never really ventured out of the house much at all. Those few experiences piqued an interest in her but she sensed the panic just below the surface with her mother. So, she thought it best not to ask too many questions.Finally one night, at sixteen, she slipped out of the back door and headed up the railroad tracks. She had decided that it was time to really live or die but a half grey life was more than she could endure.