COVID-19 containment on a college campus via wastewater-based epidemiology, targeted clinical testing and an intervention

Abstract

Wastewater-based epidemiology has potential as an early-warning tool for determining the presence of COVID-19 in a community. The University of Arizona (UArizona) utilized WBE paired with clinical testing as a surveillance tool to monitor the UArizona community for SARS-CoV-2 in near real-time, as students re-entered campus in the fall. Positive detection of virus RNA in wastewater lead to selected clinical testing, identification, and isolation of three infected individuals (one symptomatic and two asymptomatic) that averted potential disease transmission. This case study demonstrated the value of WBE as a tool to efficiently utilize resources for COVID-19 prevention and response. Thus, WBE coupled with targeted clinical testing was further conducted on 13 dorms during the course of the Fall semester (Table 3). In total, 91 wastewater samples resulted in positive detection of SARS-CoV-2 RNA that successfully provided an early-warning for at least a single new reported case of infection (positive clinical test) amongst the residents living in the dorm. Overall, WBE proved to be an accurate diagnostic for new cases of COVID-19 with an 82.0% positive predictive value and an 88.9% negative predictive value. Increases in positive wastewater samples and clinical tests were noted following holiday-related activities. However, shelter-in-place policies proved to be effective in reducing the number of daily reported positive wastewater and clinical tests. This case study provides evidence for WBE paired with clinical testing and public health interventions to effectively contain potential outbreaks of COVID-19 in defined communities.

Enumerating asymptomatic COVID-19 cases and estimating SARS-CoV-2 fecal shedding rates via wastewater-based epidemiology

“…Grab samples collected at the same time of each sampling day were considered adequate based on a prior multiple sampling event. In that case, multiple samples were collected at a particular site over a 30-minute period, and analysis indicated virtually identical virus concentrations (Betancourt et al, 2021). This suggest that virus particles disperse upon entering the piping/sewer and remain in the sewer for extended periods of time rather than being removed by plug flow (Manor et al, 2014).…”

“…Positive detection of SARS-CoV-2 RNA (via N1 and N2 gene regions) in wastewater was utilized as a leading indicator of the presence of SARS-CoV-2 infections within the dorm communities. Results were immediately communicated to the UA Task Force and Campus Re-Entry Working Groups, which planned and conducted clinical testing of residents as a response action(s), as previously described (Betancourt et al, 2021).…”

“…Clinical testing of non-self-reporting (i.e., asymptomatic and sub-clinical) students and employees was conducted through the TATS program that runs several testing locations on campus and mobilizes pop-up sites as needed (i.e., targeted clinical testing at dorms with positive wastewater detection of SARS-CoV-2). A negative antigen test at CHS, where patients were exhibiting symptoms, was followed by PCR testing to confirm results; data was de-duplicated in situations when both testing methods were used to confirm test results (Betancourt et al, 2021). To ensure compliance with the Human Subjects Protection Program (HSPP), the use of clinical data was reviewed and approved by a UArizona Institutional Review Board (IRB).…”

“…The rationale for this approach is: 1) Residual virus-shed from individuals testing positive for COVID-19 the day prior to sampling-may be detected in wastewater the following day. Previous sampling indicates that virus can persist for extended periods of time and be detected even when an estimated 1000 gallons of wastewater has continued to flow through a sewer system (Betancourt et al, 2021).…”

“…This research aims to estimate SARS-CoV-2 fecal shedding rates in infected persons by aggregating data from positive wastewater samples with numbers of known symptomatic and asymptomatic individuals in defined communities. To that end, the Campus Re-entry study at the UArizona in Fall 2020 (Betancourt et al, 2021) provided a unique setting to calculate mean shedding rates for defined communities. Specifically, 13 dorms served as a case study to test the utility of WBE to monitor SARS-CoV-2 levels in sewage and initiate public health action based upon those results.…”