Health officials on Thursday confirmed that the first known U.S. case of polio in nearly a decade was detected in an unvaccinated adult in Rockland County, New York, underscoring the importance of routine childhood immunizations.

Polio was just found in the UK. Will the US be next?

U.S. detects first known case of polio since 2013

According to the New York State Department of Health (NYSDOH) and the Rockland County Department of Health (RCDOH), CDC confirmed that an unidentified individual was infected with revertant polio Sabin type 2 virus.

"This is indicative of a transmission chain from an individual who received the oral polio vaccine (OPV)," according to a statement from NYSDOH. "This suggests that the virus may have originated in a location outside of the U.S. where OPV is administered, since revertant strains cannot emerge from inactivated vaccines."

About a month ago, the individual started experiencing symptoms, including "weakness and paralysis," said Rockland County Health Commissioner Patricia Schnabel Ruppert. According to Ruppert, the health department was informed last Monday about the confirmed case.

"We are now surveying the family and close contacts of this individual to assess the risk to the community," Ruppert said. However, she did not disclose any additional information about the patient's current condition or prognosis.

"I want to stress that this individual is no longer contagious," said Rockland County Executive Ed Day. "Our efforts now are focused on two issues: vaccinations and figuring out if anyone else has been impacted by this disease."

Separately, Ruppert noted the agency "is working with our local health care partners and community leaders to notify the public and make polio vaccination available."

"We are monitoring the situation closely and working with the New York State Department of Health and the Centers for Disease Control and Prevention to respond to this emergent public health issue to protect the health and well-being of county residents," she added.

Health officials encourage vaccination

While NYSDOH and RCDOH officials did not disclose many details about the patient, local officials said he is a man from the Orthodox Jewish community.

Notably, in 2018 and 2019, Rockland County experienced a measles outbreak that was centered in the ultra-Orthodox Jewish community, whose vaccination rates are typically lower than the general population. During that outbreak, over 150 individuals were infected with the measles.

Now, health officials are concerned that Rockland County might be at risk for additional vaccine-derived polio cases.

On Friday, Rockland County began operating local vaccine clinics for unvaccinated individuals, those who did not complete a standard polio vaccine series during childhood, or members of the community who are worried about exposure. While individuals who have already been vaccinated are considered low risk, they can still receive a booster dose if they are at risk of being exposed.

In a statement, CDC said, "Most of the U.S. population has protection against polio because they were vaccinated during childhood, but in some communities with low vaccine coverage, there are unvaccinated people at risk. Polio and its neurologic effects cannot be cured, but can be prevented through vaccination."

"Based on what we know about this case, and polio in general, the Department of Health strongly recommends that unvaccinated individuals get vaccinated or boosted with the FDA-approved [injected inactivated polio vaccine] as soon as possible," said New York State Health Commissioner Mary Bassett.

"The polio vaccine is safe and effective, protecting against this potentially debilitating disease, and it has been part of the backbone of required, routine childhood immunizations recommended by health officials and public health agencies nationwide," Bassett added.

"I think it's concerning because … it can spread," said Walter Orenstein, a polio expert at Emory University. "If there are unvaccinated communities, it can cause a polio outbreak."

"The inactivated polio vaccine we have is very effective and very safe and could have prevented this," he added. "We need to restore our confidence in vaccines."

"Vaccines have protected our health against old and new viruses for decades," said New York City Health Commissioner Ashwin Vasan. "The fact is, the urgency of safe and effective vaccines has always been here, and we need New Yorkers to protect themselves against completely preventable viruses like polio." (Branswell, STAT News, 7/21; Archie, NPR, 7/21; Santucci, USA Today, 7/21; Meko, New York Times, 7/21; Lou, MedPage Today, 7/21; Young, Politico, 7/21; Saric, Axios, 7/21)