A family in Indiana that decided not to vaccinate their 3-year-old daughter is now haunted by decision, wondering if a flu shot could have saved her life.

Alivia Viellieux, of Muncie, Indiana, died Monday morning just days after being diagnosed. The little girl's grandmother, Tameka Steller, said the family is second-guessing the decision not to vaccinate her, ABC News reports.

The grandmother said Alivia's parents declined to get the little girl a flu shot after hearing that the vaccination could be ineffective. The family was preparing to celebrate Alivia's fourth birthday next month.

The clinic said Alivia tested positive for Influenza A. She was sent to the emergency room at Ball Memorial Hospital, where she stayed for three days. She was sent home on Thursday after she appeared to be doing better, but ABC reports that the progress didn't last.

The little girl died in her sleep on Monday morning. The exact cause of Alivia's death has not been determined.