School nurses mistakenly gave the swine flu vaccine to two students who didn't sign up for it - including a Brooklyn girl with epilepsy who wound up in the hospital.

"I was outraged," Naomi Troy, 26, told the Daily News after her 6-year-old daughter, Nikiyah Torres-Pierre, had a possible allergic reaction to the shot.

Officials at Public School 335 in Crown Heights called an ambulance to take Nikiyah to SUNY Downstate Medical Center when she fell ill following the arm jab.

"My stomach was hurting, and I was itching," Nikiyah said after she was released from the hospital.

The snafu and a similar mixup at a Staten Island school came in the first days of the city's in-school H1N1 vaccination program.

City officials have stressed the vaccine is safe and urged parents to sign up for it - though less than half have sent in permission slips.