This graph is amazing. It shows that measuring #SARSCoV2 levels in municipal sewage almost perfectly predicts forthcoming #COVID19 cases with a full week’s notice (R=0.994). It’s one of several discoveries in this new study from
@Yale: https://medrxiv.org/content/10.1101/2020.05.19.20105999v1.full.pdf. C-19 is #InThePoop
— Brennan Spiegel, MD, MSHS (@BrennanSpiegel) 10:16 PM – 25 May 2020
We report a time course of SARS-CoV-2 RNA concentrations in primary sewage sludge during the Spring COVID-19 outbreak in a northeastern U.S. metropolitan area. SARS-CoV-2 RNA was detected in all environmental samples and, when adjusted for the time lag, the virus RNA concentrations were highly correlated with the COVID-19 epidemiological curve (R2=0.99) and local hospital admissions (R2=0.99). SARS-CoV-2 RNA concentrations were a seven-day leading indicator ahead of compiled COVID-19 testing data and led local hospital admissions data by three days. Decisions to implement or relax public health measures and restrictions require timely information on outbreak dynamics in a community.
The most common metric followed to track the progression of the COVID-19 epidemic within communities is derived from testing symptomatic cases and evaluating the number of positive tests over time.1 However, tracking positive tests is a lagging indicator for the epidemic progression.2, 3 Testing is largely prompted by symptoms, which may take up to five days to present4, and individuals can shed virus prior to exhibiting symptoms. There is a pressing need for additional methods for early sentinel surveillance and real-time estimations of community disease burden so that public health authorities may modulate and plan epidemic responses accordingly.
SARS-CoV-2 RNA is present in the stool of COVID-19 patients5-7 and has recently been documented in raw wastewater.8-10 Thus, monitoring raw wastewater (sewage) within a community’s collection system can potentially provide information on the prevalence and dynamics of infection for entire populations.11 When municipal raw wastewater discharges into treatment facilities, solids are settled and collected into a matrix called (primary) sewage sludge, which has been shown to contain a broad diversity of human viruses including commonly circulating coronavirus strains.12 Primary sludge provides a well-mixed and concentrated sample that may be advantageous for monitoring SARS-CoV-2. As viral shedding can occur before cases are detected, we hypothesize that the time course of SARS-CoV-2 RNA concentrations in primary sewage sludge is a leading indicator of outbreak dynamics within a community served by the treatment plant.
So in plain English, if you know what the level of SARS-CoV-2 is in your municipal wastewater, you will have a very accurate predictor of the new COVID-19 case rate in your community. And guess what? The city of Houston is tracking this very data. I don’t know if it’s being published anywhere, but it sure could shed some light on how things are really going around here. Other cities should be doing this as well – if they aren’t doing it already, they need to start – and that information should be collected and published at the state level as well. What are we waiting for?