ABSTRACT
Wastewater-based epidemiology (WBE) has been utilized for outbreak monitoring and response efforts in university settings during the coronavirus disease 2019 (COVID-19) pandemic. However, few studies examined the impact of university policies on the effectiveness of WBE to identify cases and mitigate transmission. The objective of this study was to retrospectively assess relationships between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wastewater outcomes and COVID-19 cases in residential buildings of a large university campus across two academic semesters (August 2020-May 2021) under different COVID-19 mitigation policies. Clinical case surveillance data of student residents were obtained from the university COVID-19 response program. We collected and processed building-level wastewater for detection and quantification of SARS-CoV-2 RNA by RT-qPCR. The odds of obtaining a positive wastewater sample increased with COVID-19 clinical cases in the fall semester (OR = 1.50, P value = 0.02), with higher odds in the spring semester (OR = 2.63, P value < 0.0001). We observed linear associations between SARS-CoV-2 wastewater concentrations and COVID-19 clinical cases (parameter estimate = 1.2, P value = 0.006). Our study demonstrated the effectiveness of WBE in the university setting, though it may be limited under different COVID-19 mitigation policies. As a complementary surveillance tool, WBE should be accompanied by robust administrative and clinical testing efforts for the COVID-19 pandemic response. © 2022 American Chemical Society.
ABSTRACT
Wastewater-based epidemiology (WBE) has been utilized for outbreak monitoring and response efforts in university settings during the coronavirus disease 2019 (COVID-19) pandemic. However, few studies examined the impact of university policies on the effectiveness of WBE to identify cases and mitigate transmission. The objective of this study was to retrospectively assess relationships between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wastewater outcomes and COVID-19 cases in residential buildings of a large university campus across two academic semesters (August 2020-May 2021) under different COVID-19 mitigation policies. Clinical case surveillance data of student residents were obtained from the university COVID-19 response program. We collected and processed building-level wastewater for detection and quantification of SARS-CoV-2 RNA by RT-qPCR. The odds of obtaining a positive wastewater sample increased with COVID-19 clinical cases in the fall semester (OR = 1.50, P value = 0.02), with higher odds in the spring semester (OR = 2.63, P value < 0.0001). We observed linear associations between SARS-CoV-2 wastewater concentrations and COVID-19 clinical cases (parameter estimate = 1.2, P value = 0.006). Our study demonstrated the effectiveness of WBE in the university setting, though it may be limited under different COVID-19 mitigation policies. As a complementary surveillance tool, WBE should be accompanied by robust administrative and clinical testing efforts for the COVID-19 pandemic response.
ABSTRACT
BACKGROUND: COVID-19 patients can have persistent viral stool positivity despite negative respiratory samples, irrespective of symptoms. These patients could potentially go undetected under the current pre-endoscopy COVID-19 testing guidance recommendations. However, the clinical significance of viral RNA in the stool remains unclear. AIMS: We aimed to prospectively determine whether SARS-CoV-2 is detected via real-time reversetranscriptase polymerase chain reaction (rRT-PCR) in the GI tract of patients scheduled for endoscopy and if the virus obtained from these clinical specimens could be isolated in culture. METHODS: All patients underwent symptom screening and had negative nasopharyngeal testing for SARS-CoV-2 within 72 hours of their scheduled procedure. Study samples were collected via repeat nasopharyngeal swab, rectal swab, and fluid from the upper GI tract and/or colon based on their endoscopic procedure(s). Samples were tested for SARSCoV-2 via rRT-PCR. Clinical specimens confirmed to be positive for SARS-CoV-2 RNA were then isolated and cultured in Vero-E6 cells. RESULTS: 243 patients (mean age 63.1 years;54.3% men) were enrolled from July 15th, 2020 to September 2nd, 2020 (Table 1). Most patients (177;72.8%) were asymptomatic, with nausea/vomiting (23;9.5%) being the most commonly reported COVID-19 related symptom. SARS-CoV-2 testing was performed from 242(99.6%) nasopharyngeal, 243(100%) rectal, 183(75.3%) upper GI tract and 73(30%) colon samples. Only 1 patient (0.4%), with a history of COVID-19 infection 45 days prior to endoscopy, tested positive for SARS-CoV-2 on all the GI clinical specimens (fluid from upper GI tract, colon, and rectal swab), despite being asymptomatic and having 3 negative nasopharyngeal swabs 40, 37 and 3 days before her procedure (Figure 1). After 14-day incubation period, there was no evidence of virus growth in cells incubated with any of these specimens. CONCLUSIONS: SARS-CoV-2 is rarely detected in the GI tract of patients with negative screening nasopharyngeal COVID-19 testing prior to endoscopy. Infectious virus was not detected by culture from any of the GI specimens positive for SARS-CoV-2 RNA by rRT-PCR. Our results further highlight that presence of viral genome on its own is not sufficient proof of infectivity. Additional studies are needed to evaluate the temporal association between COVID-19 symptom onset and potential infectivity duration in the GI tract. (Table Presented)(Figure Presented)