Relationships between SARS-CoV-2 in Wastewater and COVID-19 Clinical Cases and Hospitalizations, with and without Normalization against Indicators of Human Waste

Abstract

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in wastewater has been used to track community infections of coronavirus disease-2019 (COVID-19), providing critical information for public health interventions. Since levels in wastewater are dependent upon human inputs, we hypothesize that tracking infections can be improved by normalizing wastewater concentrations against indicators of human waste [Pepper Mild Mottle Virus (PMMoV), β-2 Microglobulin (B2M), and fecal coliform]. In this study, we analyzed SARS-CoV-2 and indicators of human waste in wastewater from two sewersheds of different scales: a University campus and a wastewater treatment plant. Wastewater data were combined with complementary COVID-19 case tracking to evaluate the efficiency of wastewater surveillance for forecasting new COVID-19 cases and, for the larger scale, hospitalizations. Results show that the normalization of SARS-CoV-2 levels by PMMoV and B2M resulted in improved correlations with COVID-19 cases for campus data using volcano second generation (V2G)-qPCR chemistry (r s = 0.69 without normalization, r s = 0.73 with normalization). Mixed results were obtained for normalization by PMMoV for samples collected at the community scale. Overall benefits from normalizing with measures of human waste depend upon qPCR chemistry and improves with smaller sewershed scale. We recommend further studies that evaluate the efficacy of additional normalization targets.

Wastewater-Based Epidemiology for SARS-CoV-2 Biomarkers: Evaluation of Normalization Methods in Small and Large Communities in Southern Germany

“…This is in agreement with previous studies: Whereas Graham et al 33 stated no substantial improvement when normalizing by surrogate viruses and Ai et al 17 and Xie et al 34 observed a deterioration of correlation with clinical data, Wilder et al 35 found considerable positive correlations only when normalizing by CrAssphage. Further studies, comparing different sampling sites, reported improvements of the correlation for some locations but deteriorations for others 18,24,45 .…”

Application of neighborhood-scale wastewater-based epidemiology in low COVID-19 incidence situations

“…In addition, as suggested in previous studies (Simpson et al, 2021; U.S. CDC, 2022a; Wolfe et al, 2021; Zhan et al, 2022), we presented SARS-CoV-2 RNA concentrations normalized to PMMOV, an indicator for human fecal matter, for comparisons with clinical epidemiology.…”

“…CL indicates the lowest N gene concentration from samples that do not have undetermined qPCR results. In addition, as suggested in previous studies (Simpson et al, 2021;Wolfe et al, 2021;Zhan et al, 2022), we presented SARS-CoV-2 RNA concentrations normalized to PMMOV for comparisons with clinical epidemiology.…”

Wastewater surveillance of influenza activity: Early detection, surveillance, and subtyping in city and neighbourhood communities

“…3). PMMoV has been recommended as a suitable normalizing factor enabling identification of trends in part due to stability in wastewater and low temporal variation in concentration, particularly when analyzing the solid fraction of wastewater 8,24,[42][43][44][45][46][47] . Mandated masking requirements in the province of Ontario, which were applied during the COVID-19 pandemic, were largely lifted on March 21, 2022.…”

“…3). PMMoV has been recommended as a suitable normalizing factor enabling identification of trends in part due to stability in wastewater and low temporal variation in concentration, particularly when analyzing the solid fraction of wastewater 8,24,[42][43][44][45][46][47] .…”