Polio found in sewage samples outside New York City suggests it's spreading in the community, health officials says

Polio has been found in wastewater samples taken from two counties outside of New York City indicating the virus is spreading in the community, according to state health officials.

Wastewater samples taken from two different locations in Orange County during June and July tested positive for the virus, according to the New York State Department of Health.

The findings come after an unvaccinated adult in Rockland County contracted polio, suffered paralysis and had to be hospitalized last month. Polio was subsequently found in Rockland County wastewater samples. Rockland County neighbors Orange County.

"These environmental findings — which further indicate potential community spread — in addition to the paralytic polio case identified among a Rockland County resident, underscore the urgency of every New York adult and child getting immunized against polio, especially those in the greater New York metropolitan area," New York health officials said.

The polio strain the adult in Rockland County caught suggests the chain of transmission did not begin in the United States. The strain the individual contracted is used in the oral polio vaccine, which contains a mild version of the virus that can still replicate. This means people who receive the oral vaccine can spread the virus to others.

But the U.S. hasn't used the oral polio vaccine in more than 20 years. The U.S. uses an inactivated polio vaccine that is administered as shot in the leg or arm. The vaccine uses a non-replicating virus strain, which means people who receive the shot cannot infect other people.

The polio case in New York is genetically linked to the Rockland County wastewater sample as well as samples from the greater Jerusalem area in Israel and London in the United Kingdom. Health authorities in the U.K. declared a national incident in June after they detected polio in London sewage samples.

"New Yorkers should know that this does not imply that the individual case identified in Rockland County, New York has travel history to Israel or the UK," the New York state health department said.

No polio cases have originated in the U.S. since 1979 and the nation has been considered polio free since then, according to the Centers for Disease Control and Prevention. Polio caused widespread fear in the 1940s before vaccines were available. The virus disabled more than 35,000 people every year during that time, according to the CDC.

But a successful vaccination campaign in the 1950s and 1960s dramatically reduced the number of infections. Polio cases are still reported in the U.S., but they are linked to travelers who bring the virus into the country. The case in Rockland County is the first time the U.S. has confirmed an infection since 2013. New York state last confirmed an infection in 1990.