It was, by all accounts, a fluke of a flu shot, a well-intentioned, highly recommended vaccination that went horribly wrong.

Even the young woman who felt the immediate pain, a pain that hasn’t stopped in three years, makes sure her young daughter has the same shot every year.

Jennifer Sagi’s story is not a red flag about vaccinations, although it could be, but it is about spreading the word that sometimes things go wrong.

And there are ways to make them right.

After a yearlong legal fight, Sagi received a $4.7 million settlement through a federal vaccine injury-compensation program, an obscure legal process also called “vaccine court.”

The money is intended to cover lost wages and finance a life care plan for the 31-year-old West Seneca woman whose life was shattered the day she went out for a flu shot and returned home in disabling pain.

Sagi says the needle hit a nerve that day in 2010 when she received the vaccine at the Jewish Community Center in Amherst, and it was clear right away that something was terribly wrong.

“I felt the pain immediately in my arm,” she said.

And it grew worse.

For months, doctors searched unsuccessfully for a diagnosis behind the pain, swelling and skin discoloring that Sagi experienced early on.

“I tried everything,” she said of those early months of treatments. “At one point, I thought I was going crazy.”

Finally, a pain specialist zeroed in on complex regional pain syndrome, a chronic nerve disorder that often starts in the arm or leg and spreads to the entire body. Only a handful of such cases have been reported nationally after a needle vaccination for the flu. Tens of millions of vaccines have been administered.

The syndrome has the dubious distinction of being considered a very painful, long-term condition.

“The pain is pretty intense and constant,” Sagi said. “I no longer work. I’m a few credits short of getting my degree, which I’ll never finish. I can’t even play outside with my daughter.”

Sagi walks with a cane, but pain remains a constant in her life.

She relies on a spinal cord stimulator, a battery-operated pain-relief mechanism inserted in her back. She constantly looks for new treatments.

She also remains dependent on others, one big reason why her case ended with a relatively quick and sizable settlement.

Instead of filing a traditional lawsuit, Sagi and her lawyer, Brian L. Cinelli of Williamsville, decided to go through vaccine court, a legal process formed in 1986 to address and fund the claims of people injured by vaccines.

The program was started because of concerns about high court awards deterring vaccine research. A 75-cent fee on every flu shot funds the program.

It lends itself to a quick resolution that a traditional lawsuit would not, Cinelli said of the program.

Sagi wanted justice, but she wanted it sooner rather than later.

She was out of work, and the medical bills were piling up for the former customer relations employee at a local bank. She also wanted the resources to pursue new, more costly forms of pain management.

Cinelli filed Sagi’s claim in October of last year and spent the next several months documenting the seriousness of her injury to government lawyers.

Her case was helped by the fact the federal government did not question the cause of her injury: that flu shot in 2010.

Because the Department of Justice never contested causation, that allowed Cinelli to focus on the extent of her injury.

It took a year, but the government and Sagi settled a few weeks ago, and the award was approved by one of the special masters, or judges, who oversees the vaccine court.

“I’m glad it’s over,” Sagi said. “It’s been a stressful three years. There have been a lot of ups and downs, and there were times when I wanted to give up.”

She knows all too well what she lost. Playing outside with her daughter is at the top of the list. But she doesn’t dwell on what is gone, probably forever.

Three reports appear in the national Vaccine Adverse Event Report System of complex regional pain syndrome leading to a hospitalization or prolonged hospitalization after a trivalent flu vaccine administered by needle.

The vaccine protects against three strains of flu and is the most commonly used flu vaccine.

For all influenza vaccine types, including nasal sprays and a monovalent vaccine used in 2009, six serious adverse events have been tied to complex regional pain syndrome, including a report of a patient with a permanent disability.

The amount of flu vaccine administered each year has varied. Vaccine manufacturers estimate that 138 million to 145 million doses will be produced for the United States this season, according to the Centers for Disease Control and Prevention.

The federal government receives about 30,000 reports a year for all vaccines, of which 13 percent are considered serious, according to the CDC. The system relies on voluntarily submitted reports, so it is incomplete and includes inaccuracies.

Still, Sagi is quick to suggest that despite her life-changing experience, flu shots are part of staying healthy.

“Don’t let my experiences deter you from getting a flu shot. This was just something that happened to me,” she said.

“I still take my daughter for flu shots.”

News Medical Reporter Henry L. Davis contributed to this report. email: