PLYMOUTH, Minn.--You can't tell from looking at her now, but just two weeks ago Emma Alberts, 13, was in a hospital under quarantine.
"I remember one morning I woke up and I was just like, 'Can this get any worse?'" Emma recalled.
Over Christmas vacation the teenager came down with a cough and a fever.
"I started taking Advil, Children's Motrin, but I wasn't getting better," she said.
She was in bed for about four days. Emma's mom, Brenda Alberts, said her daughter stopped eating, stopped talking, stopped texting. Call it a mother's instinct but Brenda knew it had to be something more serious than a fever.
"When I looked at her eyes, they're blue, they almost looked gray to me, and she could not get out of the shower. She literally crawled out of the shower on all fours and she said, 'Mom, something is wrong.'"
Brenda took Emma to the hospital where she tested positive for influenza B and pneumonia.
Dr. David Johnson, a physician with Fairview Clinics, said one-third of people who have the flu don't ever show symptoms. For some, including the young and healthy, the flu can quickly go from mild to fatal.
"There have been cases where people have been fine. They're at school and the next day they were coughing up blood, within a couple days were on a ventilator and within a week they are dead. So, it can be very quick," Johnson said.
So when should parents take their kids to see the doctor? Johnson said if parents feels things are getting bad quickly, seek medical attention right away.
Johnson and many other doctors also say flu shots are the best protection. Emma and her younger brother did not get flu shots this year. Emma's brother also got the flu but he was over it within a few days. It took nine days for Emma to fight her way back to health. She's now back at school and healthy.