CHICAGO -- The Chicago Department of Public Health (CDPH) will expand its existing wastewater surveillance program to begin testing for poliovirus.  

Wastewater testing began this week to analyze water samples collected from area reclamation plants that serve the City of Chicago and surrounding Cook County suburbs. This effort is a collaboration between CDPH and scientists from the University of Illinois Chicago, the Regional Innovative Public Health Laboratory at Rush University Medical Center, the University of Illinois System’s Discovery Partner Institute, the Illinois Department of Public Health, the Metropolitan Water Reclamation District of Greater Chicago, and the Centers for Disease Control and Prevention. As part of this surveillance, wastewater samples will be routinely collected and processed for laboratory testing for poliovirus to see if poliovirus is present and understand if the type of poliovirus found is of concern.  

While no case of paralytic polio has been identified in Chicago or Illinois at this time, CDPH is proactively building its local capacity to detect and respond to any potential case of polio. The best way to protect everyone from polio is to maintain high immunity against poliovirus in the population through vaccination. 

In July 2022, a case of paralytic polio was identified in a New York State resident, and further wastewater testing detected poliovirus in water samples collected across multiple counties with low polio vaccination rates, suggesting likely local circulation of the virus in those community areas.  

Finding poliovirus in wastewater indicates that someone in the community is shedding poliovirus. Wastewater data cannot be used to determine or identify who is infected or how many people or households are affected, but it can enhance other data and surveillance methods used to prevent polio. Not all potential detections will be cause for concern. However, if specific strains of poliovirus are found in communities that have low vaccination rates, it can spread among unvaccinated individuals, putting them at risk for becoming infected and developing polio. Anyone who is unvaccinated or incompletely vaccinated is at risk for developing paralysis if infected with poliovirus. 

“Polio has been eradicated in the US since 1979; however, a recent case in 2022 in New York State highlights the importance of rapid detection to interrupt any new outbreaks and strengthen routine immunization, which is the best national defense against polio,” said CDPH Deputy Commissioner Massimo Pacilli.  

Polio can lead to permanent paralysis of the arms and legs and can be fatal due to paralysis in the muscles used to breathe or swallow. Most people infected with the virus do not have any symptoms, though some will have flu-like symptoms, like sore throat, fever, tiredness, nausea, and stomach pain. One in 25 people with poliovirus infection will get meningitis and about one in 200 will become paralyzed. While there is no cure for polio, it is preventable through safe and effective immunization. In the United States, the risk of getting polio is extremely low. Most people are vaccinated against polio during childhood, and this provides protection against serious illness, including paralytic polio. Studies suggest people who completed their polio vaccination during childhood are likely protected throughout adulthood.  

Improving vaccination coverage, rapid reporting, and national case surveillance are the keys to preventing cases of paralytic polio. The complete recommended polio vaccination series is extremely effective in preventing paralytic polio, and the vaccine protects against severe disease in almost everyone who has received the recommended doses. Illinois’ Vaccines for Children (VFC) program offers vaccines at no cost to eligible children through health care providers enrolled in the program, including uninsured, underinsured and Medicaid eligible children. You can find a vaccine provider by visiting http://vfc.illinois.gov/search/. Additionally, CDPH operates two immunization clinics where children and young adults 18 years of age and under can get required and recommended vaccinations at no cost.  Get more information online from CDPH about the clinics, including locations and hours: https://www.chicago.gov/city/en/depts/cdph/supp_info/health-protection/immunizations_walk-inclinics.html  

Additionally, adults and children traveling to countries where poliovirus is circulating, should get updated polio vaccinations before travel. Primary care providers, travel clinics as well as pharmacies can provide pre-travel vaccinations to adults.  

CDPH’s current program routinely tests wastewater samples across the city of Chicago to monitor SARS-CoV-2 and influenza and provides monthly updates for the public on its website: https://www.chicago.gov/city/en/sites/covid-19/home/covid-19-wastewater-surveillance.html Additional SARS-CoV-2 wastewater data for the greater Chicago area is available at https://iwss.uillinois.edu/.

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