Lessons learned from upstream wastewater sampling in response to poliovirus in New York State.

Emerging infectious diseases present a serious challenge for local health departments, and wastewater testing for pathogen surveillance is one approach to improve response preparedness. Sample collection is routinely conducted at wastewater treatment plants, and samples from wastewater treatment plants can conveniently be used for infectious disease surveillance. The sensitivity of wastewater surveillance for detecting emerging pathogens, however, is lower in high-population areas. In response to a paralytic polio case in Rockland County, the New York State wastewater surveillance network implemented wastewater surveillance in the immediate and neighboring counties, and additional wastewater surveillance at sampling points upstream from the wastewater treatment plants where positive samples were detected. The purpose of this paper is to describe the lessons learned from the rapid emergency deployment of upstream sampling in response to the poliovirus outbreak. Sampling upstream from the treatment plants at manholes in the system reduced the total sampled population in the primary treatment plant serving Rockland County from roughly 201,000 to sub-area populations ranging from roughly 3100 to 78,300, enabling more precise identification of where polio transmission was occurring. Detections across several of these upstream areas confirmed that poliovirus was not isolated to a single individual case or limited to a specific community. Maintaining upstream sampling was challenged by a lack of dedicated staff and funding. Implementation of upstream sampling highlighted the importance of preparation, including underlying data of the sewer infrastructure, coordination between government agencies, and readiness with sampling equipment. As the threat of emerging infectious diseases increases, due in part to increased vaccine hesitancy, well-planned upstream wastewater sampling strategies by health departments should be considered as additional outbreak response tools.