The Centers for Disease Control and Prevention (CDC) will strategically expand wastewater testing for poliovirus in select jurisdictions across the country. The Michigan Department of Health and Human Services (MDHHS) and Philadelphia Department of Public Health (PDPH) are among the first locations to explore plans to start collecting wastewater samples in specific communities for analysis at CDC’s polio laboratory. Preliminary discussions with select other state and local health departments are underway.
The findings from CDC’s strategic wastewater testing effort will help jurisdictions prioritize vaccination efforts in identified communities of concern. Wastewater testing will occur in certain counties with potentially low polio vaccination coverage, or counties with possible connections to the at-risk New York communities that are linked to a single case of paralytic polio in Rockland County, New York. Once initiated, testing will last at least four months. MDHHS and PDPH are collaborating with CDC to identify communities that are under-vaccinated for poliovirus and have wastewater sampling locations.
“Wastewater testing can be an important tool to help us understand if poliovirus may be circulating in communities in certain circumstances,” said Dr. José R. Romero, director of CDC’s National Center for Immunization and Respiratory Diseases. “Vaccination remains the best way to prevent another case of paralytic polio, and it is critically important that people get vaccinated to protect themselves, their families and their communities against this devastating disease.”
It’s important to note that wastewater testing for poliovirus is different from that for other pathogens such as COVID-19. Poliovirus wastewater testing is not routinely or broadly recommended, and there are strict laboratory safety requirements. However, the strategic use of wastewater testing in a limited number of at-risk communities can help determine if poliovirus is present in other parts of the United States and can be used to target vaccination efforts to rapidly improve local polio vaccination coverage if needed. Over the next few months, CDC will assist the selected jurisdictions in testing wastewater and will support them in responding to positive wastewater detections and improving vaccination rates if requested.
Finding poliovirus in sewage or 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 that are used as part of polio prevention programs, including rapid investigation of suspected polio cases.
It would not be surprising if poliovirus is detected by testing wastewater because strains of poliovirus can be shed in people’s stool without symptoms, putting unvaccinated people at risk. However, not all potential detections will be cause for concern. In the United States, the risk to the public is low because most people – greater than 92% of Americans – were vaccinated during childhood. 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. Access to clean drinking water, modern sewage systems and wastewater management further help prevent viruses like poliovirus from spreading.
When poliovirus is found in communities that have low vaccination rates, it can spread among unvaccinated individuals, putting them at risk for becoming infected and developing polio. Improving vaccination coverage, rapid reporting and national case surveillance are the keys to preventing additional cases of paralytic polio in the United States.