A four-year-old Iowa girl was left blind, with an unclear prognosis of whether she will regain her sight, after her family failed to get her vaccinated for the flu this season, according to NBC News.

Amanda Phillips said she took her daughter, Jade DeLucia, to the hospital Christmas Eve with a dangerously high fever, according to NBC News. “I looked down at her and her eyes were in the back of her head,” Phillips told the network.

Phillips said she got her daughter vaccinated last March but did not get her vaccinated again this season, hoping the earlier vaccination would be sufficient.

DeLucia was hospitalized for more than two weeks, during which time she developed encephalopathy and lost her vision, according to NBC. The swelling of the brain is an extremely rare condition, affecting about 1 in 5 million people.

Phillips said doctors told her they will not know for sure whether her daughter’s blindness is permanent for about six months, according to NBC.

A December survey found 37 percent of Americans said they did not plan on getting a flu shot during flu season.

“Widespread misconceptions exist regarding the safety and efficacy of flu shots," Caitlin Oppenheimer, senior vice president of public health research at NORC at the University of Chicago, said in December. “Because of the way the flu spreads in a community, failing to get a vaccination not only puts you at risk but also others for whom the consequences of the flu can be severe."

The Centers for Disease Control and Prevention said this year's flu has hit children especially hard. 

The agency estimates that at least 9.7 million people have had the flu this season, with 87,000 hospitalizations and 4,800 deaths reported so far.

Phillips said she hopes her daughter's story reaches other parents.

“You do what's best for your children,” she said. “You know your children."