READ THIS NEXT: If You Notice a Blister Here, Get a Blood Test, Experts Say. Polio had long been one of the most feared diseases in the U.S. before it was declared eliminated in the country in 1979, the AP reported. The virus “can infect a person’s spinal cord, causing paralysis,” according to the CDC. Rockland County Health Commissioner Patricia Schnabel Ruppert said the 20-year-old man began experiencing weakness and paralysis in June following infection with the poliovirus, per CNN.ae0fcc31ae342fd3a1346ebb1f342fcb “Paralysis is the most severe symptom associated with polio, because it can lead to permanent disability and death,” the CDC further explains. “Between 2 and 10 out of 100 people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe.” Before polio was eliminated in the U.S., there used to be annual outbreaks causing thousands of cases of paralysis, per the AP. But over the last several decades, there have only been rare cases of travelers bringing polio infections into the country. The last incident was in 2013, when a 7-month-old who had recently moved from India was diagnosed with polio in San Antonio, Texas. The young man in Rockland County did not recently travel outside of the country, however. Officials said it appeared that the patient had contracted a vaccine-derived strain of the virus, likely from someone who got a live polio vaccine—which is available in other countries but not the U.S.—and spread it. To make matters worse, on Aug. 4, New York state health officials sounded a new alarm on possible “community spread,” revealing that the polio virus has now been found in seven different wastewater samples in two adjacent counties north of New York City, the AP reported. “New Yorkers should know that for every one case of paralytic polio observed, there may be hundreds of other people infected,” New York State Health Commissioner Mary T. Bassett said in a statement. “Coupled with the latest wastewater findings, the Department is treating the single case of polio as just the tip of the iceberg of much greater potential spread. As we learn more, what we do know is clear: the danger of polio is present in New York today.” RELATED: For more up-to-date information, sign up for our daily newsletter. With the potential for this dangerous virus to spread, New York state health officials are issuing urgent calls for unvaccinated people to get inoculated against polio. “We must meet this moment by ensuring that adults, including pregnant people, and young children by 2 months of age are up to date with their immunization—the safe protection against this debilitating virus that every New Yorker needs,” Bassett said. According to the AP, the 20-year-old Rockland patient was unvaccinated against polio. In the U.S., vaccines for the virus were introduced in 1955, helping the number of polio cases fall rapidly from more than 15,000 in the ’50s to fewer than 100 in the ’60s and fewer than 10 in the ’70s, according to the CDC. “The best way to keep people safe from polio is to maintain high immunity (protection) against polio in the population through vaccination,” the CDC says. The CDC recommends that “for best protection,” children get four doses of the polio vaccine starting when they’re just two months old. This is because the inactivated poliovirus vaccine (IPV)—which is the only one used in the U.S. since 2000—provides around 90 percent immunity against all types of poliovirus after two doses, and at least 99 percent immunity after three doses. “There is no cure for polio, but it is preventable through safe and effective vaccination,” the CDC says. While there is no federal law in the U.S. mandating polio vaccination, all 50 states and Washington, D.C, have state laws requiring children who are entering childcare or public school to have gotten the vaccine, according to Newsweek. But as the AP reported, vaccination rules in some areas have become more lax over time. Now in Rockland County, only 60 percent of people have completed their polio vaccination series. “This isn’t normal. We don’t want to see this,” Jennifer Nuzzo, DrPH, a Brown University pandemic researcher, told the AP. “If you’re vaccinated, it’s not something you need to worry about. But if you haven’t gotten your kids vaccinated, it’s really important that you make sure they’re up to date.”