Her father, Eric Chason, informed the public through a posting on Facebook around 10 p.m.
- I'm sorry to have to tell everyone that Lillian died this afternoon at 5:20 PM. Her sat's kept dropping during the day and Dr Charles said that the ECMO machine could no longer keep her supported. As you all know, she put up an incredible fight and if there was anyway she could have overcome this disease, she would... have. We want to say thanks again to the wonderful people at the UNC hospital who have been and remain incredibly supportive. And thank you all for all your prayers and kind thoughts- it was an incredible comfort during this long difficult journey.
Lillian was an amazing young woman and we will miss her terribly.
Several thousand people have responded on Facebook, leaving their condolences and well wishes.
Chason was one of the rare people who suffered severe H1N1 complications even though she didn't have other medical problems and doctor's aren't sure why.
Chason had been in the hospital since November 20.
Her death comes a day after students at UNC held a blood drive to donate blood for the life support machine she was on.
Chason was on an ECMO (Extracorporeal Membrane Oxygenation) machine that oxygenated her blood and took the pressure off her lungs.
Chason's doctor, Charles Van Der Horst with UNC Hospitals says many swine flu cases involve young, vibrant, healthy people just like Chason.
It's unclear if the vaccine could've saved her life, but it has the potential to save others.
"I urge people to continue to get vaccinated, because there is plenty of H1N1 vaccine around," Van der Horst said.
Anyone who'd like to send their condolences can go to her Facebook page.
Next spring, Chason was set to play the lead in "A Dress for Mona," the story of a young girl persecuted for her faith - a role her professors say she embraced wholeheartedly.
"We're doing this for both Mona, this young woman who died in Iran, and now we're doing it for Lillian as well," play director Joseph Megel said.
"One thing I'm happy for is we were able to give her, her happiness," UNC Dramatic Art Lecturer Mark Perry said. "We were able to spend time with her, otherwise like many people we might not have had a chance to know her."
Friends and classmates held a vigil at the UNC Center for Dramatic Art Thursday evening in memory of Chason.
"All these people survived and she's that one person in this one play that got it and got pneumonia and passed and so randomly, it's just I don't know," UNC freshman Jonathan Beckles said. "It doesn't make sense."