Supporting a nationwide Covid-19 wastewater monitoring program

From June to August 2021, the U.S. Department of Health and Human Services, in collaboration with the Centers for Disease Control and Prevention, conducted the second phase of a national Covid-19 wastewater monitoring program. Through this program, >6,000 wastewater samples were collected from over 362 municipal wastewater treatment facilities across all 50 states, the District of Columbia, and 2 US territories, covering 98 million people, or 30% of all Americans. Concerns for equity guided onboarding goals, and participating plants included rural and urban communities as well as 9 tribal Indian territories. Collected samples were processed by a commercial vendor. Measured SARS-CoV-2 concentrations were uploaded into the HHS Protect and CDC NWSS databases. A subset of samples were sequenced, and viral RNA sequences were uploaded to NCBI. In multiple cases, wastewater facilities split samples, sending one aliquot to the national program vendor and another to a local university or research group, allowing for multiple real-world methodology comparison studies. Over the course of the program, key lessons about program logistics, data sharing, data quality, and data interpretation were learned. These findings and lessons should inform the design and implementation of future large-scale wastewater monitoring programs.