(CNN) — An adult from Rockland County, New York, has been diagnosed with polio, the first case identified in the United States in nearly a decade.

Young adults who were not vaccinated began experiencing weakness and paralysis about a month ago, said regional health commissioner Dr. Patricia Schnabel Ruppert, Thursday.

The case comes nearly a month after Britain’s Health Security Agency warned it had detected the polio virus in surveillance waste samples from London, suggesting some spread has occurred between closely related people in north and east London, although no cases have been identified. there.

What is polio?

Poliomyelitis is an infection caused by the polio virus. About 1 in 4 infected people have flu-like symptoms, such as sore throat, fever, fatigue, nausea, headache, and stomach pain. Up to 1 in 200 will develop more serious symptoms including tingling and numbness in the legs, infection of the brain or spinal cord and paralysis, according to the US Centers for Disease Control and Prevention. (CDC).

There is no cure for polio. It treatment to treat symptoms may include medications to relax the muscles and heat and physical therapy to stimulate the muscles. However, the paralysis caused by polio is permanent.

“This patient had weakness and paralysis,” said Schnabel Ruppert.

This is the first polio case diagnosed in the United States since 2013, according to New York Department of Health.

State and county health officials advised health care providers to keep an eye on additional cases, and advised county residents to get vaccinated against polio.

“The risk of this incident to unvaccinated members of the community is still being determined,” said Ruppert Schnabel. “We strongly advise anyone who is not vaccinated to be vaccinated.”

polio vaccine

The polio vaccine is part of the CDC’s standard immunization schedule and is mandatory for school attendance. People who have been vaccinated are not thought to be at risk.

The case in New York was identified as Sabin type 2 reverse poliovirus, which suggests that the virus came from a person who received the oral polio vaccine, which contains live but attenuated poliovirus.

Officials say this suggests the virus originated outside the US, where the oral vaccine is still being administered, but they are investigating the origins of this particular case.

Health officials said Thursday that the person had not traveled outside the US before or after the diagnosis.

Usually, people who get polio can pass it on to other people for about two weeks. Officials said the individual is not expected to be infectious at this time because that time period has passed and he has normal immune function. But others may have been exposed before the case was diagnosed.

The oral polio vaccine is no longer licensed for use in the United States. Only the inactivated polio vaccine has been given in the country since 2000.

One cannot get polio from the vaccine itself, but in recent years, polio cases associated with the elimination of the oral vaccine have emerged in communities where vaccination rates are low. Health officials believe the type of virus individuals contracted originated this way.

When this attenuated viral strain circulates in a poorly immunized population, usually in an area with poor sanitation, the virus can mutate and revert to a form that causes paralysis. This vaccine-derived virus is different from the wild poliovirus, which is currently circulating only in Pakistan and Afghanistan.

Low vaccination rate

Rockland County is home to an ultra-Orthodox Jewish community where vaccination rates have historically been very low. In 2018 and 2019, Rockland County was the epicenter of a large measles outbreak that lasted nearly a year and sickened 312 people. District health officials reported at the time that only 8% of people there had been vaccinated against measles, mumps, and rubella before the outbreak began.

“Based on what we know about this case and polio in general, the Department of Health strongly recommends that unvaccinated individuals be vaccinated or upgraded to the FDA-approved IPV polio vaccine as soon as possible,” said state health commissioner Mary T. Bassett said in a statement Thursday. “The polio vaccine is safe and effective, protects against this potentially debilitating disease, and has become part of the backbone of routine childhood immunization recommended by health officials and public health agencies across the country.” .

Cases of polio were once common in the United States and around the world. During one of the worst plagues in 1952, the virus infected 58,000 people in the US, incapacitating more than 21,000 and killing more than 3,100. However, the vaccination campaign drastically reduced cases. The last natural case of polio in the US was recorded in 1979.