A 36-year-old mom died of flu less than a day after getting sick in a '1 in a million case'

• Last Sunday was a normal, active day for Price McMahon. By Tuesday night, she'd died from the flu. 
• McMahon was a 36-year-old executive near Boston with a husband and two young kids. 
• Flu affects millions each year, but younger and older people are most likely to die from it. 

The Sunday before Christmas, 36-year-old Price Meropol McMahon ran eight miles, rooted for Argentina in the World Cup final, and celebrated the first day of Hanukkah with her family. 

But just two days later, the Wellesley, Massachusetts resident and mom of two had died from complications from the flu. The doctor said hers was a "one-in-a-million case," her brother, Ian Meropol, told the Boston Globe.

McMahon, an executive at American Express and Burberry, had no history of health issues, and was a sub-4-hour marathoner, her brother told the Globe.

And yet, she started feeling feverish Monday night and was rushed to the hospital with difficulty breathing early the next morning. She died Tuesday afternoon. 

About 8% of Americans get sick from the flu each season, according to the CDC, with children and teens under 18 at highest risk. Complications can include bacterial pneumonia, ear infections, sinus infections, and worsening of chronic illnesses.

Deaths from the flu range from hundreds to tens of thousands each year in the US, depending on the season. People under 2 and over 65 are most likely to die from the flu, especially if the older people have underlying health conditions like asthma, heart disease, or diabetes, according to the CDC. 

Flu shots reduce the risk of severe illness, and prevent millions of cases and thousands of deaths each year, the CDC said. It's unclear if McMahon was vaccinated. 

McMahon leaves behind her husband, Jimmy, of nearly 10 years, and their two children, 5-year-old James and 7-year-old Rosalie.

A GoFundMe account has been set up to assist her family McMahon family "with the many different aspects of their lives that are the unfortunate result of Price's untimely and unexpected passing," the page says. 

"Everything we are doing going forward is about Rosie, and James, and Jimmy," Meropol told the Boston Globe. "That's what our life is going to be dedicated to, forever."