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. 2022 Sep 10;838(Pt 4):156535.
doi: 10.1016/j.scitotenv.2022.156535. Epub 2022 Jun 7.

Population level SARS-CoV-2 fecal shedding rates determined via wastewater-based epidemiology

Sarah M Prasek  1 , Ian L Pepper  1 , Gabriel K Innes  2 , Stephanie Slinski  2 , Martha Ruedas  2 , Ana Sanchez  2 , Paul Brierley  2 , Walter Q Betancourt  1 , Erika R Stark  1 , Aidan R Foster  1 , Nick D Betts-Childress  1 , Bradley W Schmitz  3
Affiliations

Population level SARS-CoV-2 fecal shedding rates determined via wastewater-based epidemiology

Sarah M Prasek et al. Sci Total Environ. .

Abstract

Wastewater-based epidemiology (WBE) has been utilized as an early warning tool to anticipate disease outbreaks, especially during the COVID-19 pandemic. However, COVID-19 disease models built from wastewater-collected data have been limited by the complexities involved in estimating SARS-CoV-2 fecal shedding rates. In this study, wastewater from six municipalities in Arizona and Florida with distinct demographics were monitored for SARS-CoV-2 RNA between September 2020 and December 2021. Virus concentrations with corresponding clinical case counts were utilized to estimate community-wide fecal shedding rates that encompassed all infected individuals. Analyses suggest that average SARS-CoV-2 RNA fecal shedding rates typically occurred within a consistent range (7.53-9.29 log10 gc/g-feces); and yet, were unique to each community and influenced by population demographics. Age, ethnicity, and socio-economic factors may have influenced shedding rates. Interestingly, populations with median age between 30 and 39 had the greatest fecal shedding rates. Additionally, rates remained relatively constant throughout the pandemic provided conditions related to vaccination and variants were unchanged. Rates significantly increased in some communities when the Delta variant became predominant. Findings in this study suggest that community-specific shedding rates may be appropriate in model development relating wastewater virus concentrations to clinical case counts.

Keywords: COVID-19; Community demographics; Fecal shedding; SARS-CoV-2; Wastewater-based epidemiology.

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Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Unlabelled Image
Graphical abstract
Fig. 1
Fig. 1
Sensitivity analysis for clinical cases reported at the county and zip code level. Clinical data collected at both the county and zip code levels were adjusted based on the WRF service area. These data were compared for Community E at the beginning of the study period to inform how clinical data would be handled throughout the study (refer to 2.4, 2.8). Wilcoxon signed rank tests determined no significant difference (p-value = 0.252) between results from analysis at the county level and zip code level.
Fig. 2
Fig. 2
Fecal shedding rates across communities. Fecal shedding rates (gc/g-feces) for each community during the Spring Downturn (A) and Delta Predominant (B) stages of the pandemic. The boxes represent 50 % of the data. The horizontal line inside the box represents the mean. Whiskers represent the minimum to the lower quartile and the upper quartile to the maximum. Black dots represent outliers (>3/2 times of upper quartile or <3/2 times of lower quartile).
See this image and copyright information in PMC

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Supplementary concepts