The New York State Health Department on Thursday confirmed a case of polio and asked health-care providers to look for additional infections.
A resident of Rockland County, less than an hour outside New York City, tested positive for polio, according to the state health department. The Centers for Disease Control and Prevention confirmed the infection.
Health authorities in New York believe the case originated outside the U.S. No cases of polio have originated in the U.S. since 1979, according to the CDC.
The polio strain the individual caught, known as revertant Sabin type 2 virus, suggested the chain of infection began with someone who received the oral polio vaccine, according to the state health department. The oral polio vaccine contains a mild virus strain that is still able to replicate, which means people who receive it can spread the virus to others.
The oral polio vaccine is no longer administered in the U.S., which suggests the chain of transmission began abroad. The U.S. uses an inactivated polio vaccine that is administered as a shot in the leg or arm. This vaccinate uses a non-replicating virus strain so people who receive it cannot spread the virus to others.
The CDC recommends that all children receive the polio vaccine. New York state requires that all children receive the shot before they start school.