NEW YORK (AP) — An unvaccinated young adult from New York recently contracted polio, the first U.S. case in nearly a decade, health officials said Thursday.

Officials said the patient, who lives in Rockland County, had developed paralysis. The person developed symptoms a month ago and did not recently travel outside the country, county health officials said.

It appears the patient had a vaccine-derived strain of the virus, perhaps from someone who got live vaccine — available in other countries, but not the U.S. — and spread it, officials said.

The person is no longer deemed contagious, but investigators are trying to figure out how the infection occurred and whether other people were exposed to the virus.

Most Americans are vaccinated against polio, but this should serve as a wake-up call to the unvaccinated, said Jennifer Nuzzo, a Brown University pandemic researcher.

“This isn’t normal. We don’t want to see this,” Nuzzo said. “If you’re vaccinated, it’s not something you need to worry about. But if you haven’t gotten your kids vaccinated, it’s really important that you make sure they’re up to date.”                                                                                                                                                                           Health officials scheduled vaccination clinics in New York for Friday and Monday, and encouraged anyone who has not been vaccinated to get the shots.