Measurement of SARS-CoV-2 RNA in wastewater tracks community infection dynamics

Abstract

We measured severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA concentrations in primary sewage sludge in the New Haven, Connecticut, USA, metropolitan area during the Coronavirus Disease 2019 (COVID-19) outbreak in Spring 2020. SARS-CoV-2 RNA was detected throughout the more than 10-week study and, when adjusted for time lags, tracked the rise and fall of cases seen in SARS-CoV-2 clinical test results and local COVID-19 hospital admissions. Relative to these indicators, SARS-CoV-2 RNA concentrations in sludge were 0-2 d ahead of SARS-CoV-2 positive test results by date of specimen collection, 0-2 d ahead of the percentage of positive tests by date of specimen collection, 1-4 d ahead of local hospital admissions and 6-8 d ahead of SARS-CoV-2 positive test results by reporting date. Our data show the utility of viral RNA monitoring in municipal wastewater for SARS-CoV-2 infection surveillance at a population-wide level. In communities facing a delay between specimen collection and the reporting of test results, immediate wastewater results can provide considerable advance notice of infection dynamics. The progression of the COVID-19 pandemic has been monitored primarily by testing symptomatic individuals for the presence of SARS-CoV-2 RNA and counting the number of positive tests over time 1. However, in the United States and other countries, the spread of COVID-19 has commonly exceeded the testing capacity of public health systems. Moreover, test results are a lagging indicator of the pandemic's progression 2,3 , because testing is usually prompted by symptoms, which might take 2 weeks to present after infection 4 , and delays occur between the appearance of symptoms, testing and the reporting of test results. Monitoring sewage in a community's collection or treatment system has been used previously to provide early surveillance of disease prevalence at a population-wide level, notably for polio 5,6 , and might be similarly beneficial for the current COVID-19 pandemic. SARS-CoV-2 RNA is present in the stool of patients with COVID-19 (refs. 7-9) and in raw wastewater 10-12 , and increased RNA concentrations in raw wastewater have been recently associated with increases in reported COVID-19 cases 11. However, the utility of wastewater SARS-CoV-2 concentrations for tracking the progression of COVID-19 infections is poorly understood. In this study, we investigated how viral RNA concentrations in

Technical framework for wastewater-based epidemiology of SARS-CoV-2 based on relative quantification via qPCR

“…According to our knowledge and reported studies, the virus adsorbed on the sewage particles cannot be neglected and may even account for the major portion of the SARS-CoV-2 in the sewage [17,43]. By far the highest value of virus content ever detected in sewage-related samples is from the primary sewage sludge, and the value is as high as 4.6× 10 8 RNA copies/L [14].…”

“…Therefore, the decay rate constant and half-life at different sewage temperatures can be calculated using Eqs. (14) and (15).…”

“…The load of SARS-CoV-2 in feces is in the range 5×10 3 -10 7.6 RNA copies/mL [12]. Meanwhile, researchers all over the world have also detected the RNA of SRAS-CoV-2 from the local sewage [13][14][15][16][17][18][19][20][21][22][23]. Thus, wastewater-based epidemiology (WBE) of SARS-CoV-2 which surveys sewage for virus RNA to inform epidemiological monitoring of COVID-19 has been proposed as the most promising method to determine the burden of undiagnosed infections at the population level [24][25][26][27].…”

“…This is a challenging task for areas with high population mobility. Several studies have tried to quantify some population-related biomarkers, such as human ribonuclease P [14], creatinine, urea, benzotriazole, caffeine etc. [15,17] to achieve this goal.…”

“…and D, the values of k, t1/2 and T90 in the temperature range of 0 to 40 o C were also calculated with Eqs (14),(15). and(11), respectively.…”