NEW YORK (AP) — New York health officials on Thursday reported a polio case, the first in the U.S. in nearly a decade.

Officials said the Rockland County resident is an unvaccinated adult, but they did not detail the person’s condition.

It appears the person 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.

Polio was once one of the nation’s most feared diseases, with annual outbreaks causing thousands of cases of paralysis — many of them in children.

Vaccines became available starting in 1955, and a national vaccination campaign cut the annual number of U.S. cases to less than 100 in the 1960s and fewer than 10 in the 1970s, according to the Centers for Disease Control and Prevention.

In 1979, polio was declared eliminated in the U.S., meaning there was no longer routine spread. Rarely, travelers with polio have brought infections into the U.S., with the last such case in 2013.

U.S. children are still routinely vaccinated against polio. Federal officials recommend four doses: to be given at 2 months of age; 4 months; at 6 to 18 months; and at age 4 through 6 years. Some states require only three doses.

According to the CDC’s most recent childhood vaccination data, about 93% of 2-year-olds had received at least three doses of polio vaccine.

Polio spreads mostly from person to person or through contaminated water. It can infect a person’s spinal cord, causing paralysis and possibly permanent disability and death. The disease mostly affects children.

Polio is endemic in Afghanistan and Pakistan, although numerous countries in Africa, the Middle East and Asia have also reported cases in recent years.

Rockland County, in New York City’s northern suburbs, has been a center of vaccine resistance in recent years. A 2018-2019 measles outbreak there infected 312 people.

Last month, health officials in Britain warned parents to make sure children have been vaccinated because the polio virus had been found in London sewage samples. No cases of paralysis were reported.

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The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.