José Peralta was taken to Elmhurst Hospital Center in Queens, NY after becoming disoriented following a two-week illness, which he said began after receiving the flu shot.

NY Times reports: Mr. Peralta, a Democrat, lost his re-election bid in September after serving eight years in the State Senate representing neighborhoods in Jackson Heights, Corona, Elmhurst, East Elmhurst and portions of Woodside and Astoria.

A member of a Democratic group that caucused with Republicans, Mr. Peralta was defeated by Jessica Ramos, an insurgent from his own party riding a progressive wave. He was set to leave office at the end of December.

Mr. Peralta was first elected to the State Senate in 2010 in a special election, defeating Hiram Monserrate, who was expelled from the Senate after being convicted of assaulting his companion.

As a lawmaker, Mr. Peralta was a champion of the Dream Act, legislation that would allow undocumented immigrants to qualify for college tuition assistance. He also introduced bills to legalize hoverboards in the city and to extend the time that speed cameras are used in school zones.

Mr. Peralta, a resident of Queens for three decades, began his political career there as a community liaison to the State Assembly, the legislature’s lower house. He went on to win a seat in that body and served there for eight years.

Mr. Peralta’s campaign to become Queens borough president was derailed in 2013 when he was recorded by a state legislator in her role as an informant for the Federal Bureau of Investigation. The legislator, Shirley L. Huntley, was under investigation for corruption and hoped that cooperating with the F.B.I. by recording public officials whom she suspected were corrupt would help her case.

Mr. Peralta was not charged or accused of wrongdoing.

José Rafael Peralta was born on Nov. 10, 1971, in New York City to parents who had emigrated from the Dominican Republic. He attended public schools in Queens and graduated from Queens College, where he studied psychology and sociology and served as student body president.

Though he had been ill for at least two weeks, he had been reluctant to visit a doctor, according to Chris Sosa, his director of communications. After much prodding, he finally went for an exam recently, and he had a follow-up scheduled for December.

“It was like pulling teeth to get him to talk about not feeling well,” Mr. Sosa said. “He just thought he was having symptoms related to getting the flu shot.”

Mr. Peralta was at home with his family on Wednesday night when he became disoriented. He was taken to the Elmhurst hospital and died there at 9:23 p.m., Mr. Sosa said.

As news of the death began to spread on Thursday morning, his colleagues took to Twitter. Gov. Andrew M. Cuomo called him “a dedicated public servant” and a “relentless advocate” for Queens.

Adriano D. Espaillat, who was the first Dominican-American elected to Congress, called Mr. Peralta a “loving husband & brother who adored and protected his family.”

And Mayor Bill de Blasio wrote on Twitter: “Jose Peralta was a proud son of Queens and the Dominican Republic. He worked his way up from the grass roots, with heart and tenacity.”

Mr. Peralta lost the Democratic primary for re-election to Ms. Ramos by 10 percentage points. She went on to capture the seat in the general election.

Mr. Peralta’s defeat was fueled by anger against his participation in the Independent Democratic Conference, the group of breakaway Democrats who caucused with Republicans, effectively giving Republicans control of the Senate and preventing the passage of legislation mandating stricter gun control laws and protections for women’s reproductive rights.

The group disbanded in April, but six of the eight former members of the I.D.C. lost primary challenges as part of a wave of progressive politics that swept the country, particularly in New York.

Ms. Ramos, on Twitter, said that while she disagreed with Mr. Peralta on many issues, “he was a true public servant.”

José Peralta is gone too soon. When I met him in 2003 I saw a world of promise for our community & though years later we’d disagree on tackling the issues, I know in his heart he loved his community. He was a true public servant. Strength & love to his wife, sons, and loved ones. pic.twitter.com/r4HhjIAji1

— Jessica Ramos (@jessicaramos) November 22, 2018

Mr. Peralta had continued to serve his constituents after losing the primary. His Twitter feed showed him giving out turkeys at his office and promoting flu shots.

“He never stopped working. He was still doing stuff for the community,” Tom Musich, his campaign spokesman, said. “A lot of people, after they lose, they don’t keep doing the work.”

Thank you Senator Peralta for supporting our community this Thanksgiving Season. #Elmhurst #Corona @NYPD110PCTCC @SenatorPeralta @NYPDQueensNorth pic.twitter.com/OWK1k5Qt6w

— NYPD 110th Precinct (@NYPD110Pct) November 16, 2018

Mr. Peralta is survived by his wife, Evelyn, and two sons, Myles, 13, and Matthew, 21.

Michael Morrison, who worked as Mr. Peralta’s director of operations for 15 years, said he learned how much Mr. Peralta valued family while working with him.

“When my husband was dying of cancer, he let me work from home and spend our last hours together,” Mr. Morrison said. “I just wish Evelyn and the kids peace.”