Coupling freedom from disease principles and early warning from wastewater surveillance to improve health security

Infectious disease surveillance is vitally important to maintaining health security, but these efforts are challenged by the pace at which new pathogens emerge. Wastewater surveillance can rapidly obtain population-level estimates of disease transmission, and we leverage freedom from disease principles to make use of non-detection of SARS-CoV-2 in wastewater to estimate the probability that a community is free from SARS-CoV-2 transmission. From wastewater surveillance of 24 treatment plants across upstate New York from May through December of 2020, we observed a reliable limit of detection of 0.3--0.5 cases per 10,000 population. No COVID-19 cases were reported 40% of the time following a non-detection of SARS-CoV-2 in wastewater, and cases were less than 1 daily case per 10,000 population 97% of the time following non-detection. Trends in the intensity of SARS-CoV-2 in wastewater correlate with trends in COVID-19 incidence and test positivity (>0.5), with the greatest correlation observed for active cases and a three-day lead time between wastewater sample date and clinical test date. Wastewater surveillance can cost-effectively demonstrate the geographic extent of the transmission of emerging pathogens, confirming that transmission is absent or under control and alerting of an increase in transmission. If a statewide wastewater surveillance platform had been in place prior to the onset of the COVID-19 pandemic, policymakers would have been able to complement the representative nature of wastewater samples to individual testing, likely resulting in more precise public health interventions and policies.