(CNN/KSTU) - Thousands of people nationwide remain wary of getting an annual flu shot for a variety of reasons; namely, many people think that the shot itself will get them sick.
A worst nightmare scenario may have played out for a 19-year-old in Utah after he got his vaccination, and doctors continue to struggle to figure out why he died.
Just one month ago, Chandler Webb was a typical 19-year-old getting ready for his LDS mission when he went to a Salt Lake City-area pediatrician for a flu shot. It was the first one he had ever received.
Less than 24 hours later, Chandler fell violently ill. By Oct. 23, he was at an area hospital with a team of six doctors trying to figure out what was killing him.
"He never shook so hard his whole life," Chandler's mother, Lori Webbi, said. "They checked every virus, every tick, every fungus."
All of those tests came back negative, and physicians nearly unanimously dismissed the flu vaccine as a possibility. By the time one said that it could be linked to the vaccination, Chandler's brain had swelled.
He then slipped into a coma from which he'd never emerge.
An investigation being overseen by Utah's state epidemiologist, Dr. Allyn Nakashima, is underway. Health officials say that as far as they know, there's never been a death in Utah due to the flu vaccine, but Nakashima says it's possible.
"We certainly have seen associations of encephalitis or encephalitis-type illnesses following (the) flu vaccine," Dr. Nakashima said. "It's very rare and we can't necessarily say there's a cause and effect here. We can say there's an association."
If the flu vaccine took Chandler's life, she says that it's and extremely rare case. She hopes that it doesn't discourage the public at large from getting the shot.
"We have anywhere from 6,000 to 50,000 deaths per year due to flu in this country, and many of those could be saved by administration of the flu vaccine," she said.