Wastewater Testing for SARS-CoV-2 Surveillance 

Wastewater-Based Epidemiology is an approach for infectious disease surveillance and can serve as an early warning system for disease outbreaks (Sims and Kasprzyk-Hordern 2020). Wide application of wastewater surveillance began in the 1990s with efforts to eradicate poliovirus. Although SARS-CoV-2 is not primarily spread through fecal-oral transmission like polio, the presence of SARS-CoV-2 RNA has been detected in feces of patients. The presence of viral RNA in feces stems from the ability of the virus to infect ACE2-expressing cells in the small intestine (Zang et. al, 2020).

Currently, it is not possible to directly convert concentrations of viral RNA in wastewater to disease prevalence in a community due to variability in RNA excretion over time (Larsen and Wigginton 2020). However, following longitudinal trends of SARS-CoV-2 RNA levels in wastewater can provide information similar to that from daily random testing of hundreds of individuals in a community to understand trends in community transmission. This method would also be more cost-effective and less invasive. A study tracking the community infection dynamics through RNA concentrations in wastewater in New Haven, Connecticut for 10 weeks, found that SARS-CoV-2 RNA concentrations in sludge were 6–8 days ahead of positive test reports and 1-4 days ahead of hospital admissions (Peccia et al. 2020). This suggests the utility of utilizing wastewater testing as a real-time tool to monitor COVID-19 prevalence in specific geographic locations  and overcome limited testing capacities or delays in results. 

Universities across the United States have also recently started testing wastewater in dorms and campus buildings to monitor virus prevalence and quickly control possible outbreaks by testing individuals who may have contributed to the infected wastewater.