Wastewater testing gains support as early warning for Covid-19 - STAT

What only a month ago had been merely an intriguing laboratory finding about analyzing wastewater to detect the virus that causes Covid-19 has quickly leapt to the threshold of real-world use.

With swab tests still plagued by capacity issues, inaccuracy, and slow turnaround, testing wastewater for the novel coronavirus’ genetic signature could give communities a faster way to spot a rebound in cases — as soon as this fall.

“There is real hope that this can be a sensitive, early warning” if, as officials ease social distancing measures, Covid-19 begins to spread again, said Peter Grevatt, CEO of the nonprofit Water Research Foundation.

“Several labs have achieved a proof-of-concept in terms of demonstrating the ability to detect the RNA [genetic material] of the virus in wastewater.” Studies in the U.S.

Grevatt and his colleagues briefed congressional staffers last week on the potential for wastewater analysis to be the canary in the Covid-19 coal mine, and on Wednesday the National Academies’ Water Science and Technology Board hosted a panel discussion on how to build a surveillance network and what additional research is needed to make it work.

“These are life-and-death questions.” And although more research is needed to figure out if, for instance, the amount of virus in stool and therefore wastewater varies with the severity of disease, “this has the potential to be implemented in the current pandemic.”.

“We know that SARS-CoV-2 [the virus that causes Covid-19] is shed in stool, which means it can be collected in sewage systems,” said Megan Murray of the Harvard T.H.

In addition to detecting cases sooner, wastewater analysis can also get around the well-known limitations of the swab tests used to detect Covid-19.

And although Covid-19 testing in the U.S.

Biobot is working with about 400 water facilities in 42 states to see if wastewater epidemiology for Covid-19 in the real world can live up to the hopes inspired by early lab tests.

Doing that should be at the top of the research agenda, Grevatt said: “Work is moving in a direction where you may be able to count the cases in a community, but we aren’t there yet.” To get there, scientists must figure out when during the course of infection people shed virus in stool, whether the amount of viral shedding is the same in severe and mild or even asymptomatic cases, and whether the quality of an area’s water — mineral content, industrial effluent, and other components — affect the detection of viral genes.

Even if wastewater analysis can’t yet quantify cases, it can detect when their prevalence changes.

It is also doing its own research, trying to answer key questions such as how rain affects viral concentration, said Ken Williamson, director of regulatory affairs.

Engineers at the Southern Nevada Water Authority found high levels of five SARS-CoV-2 genes in samples taken around March 9, which lines up with when the state has its first confirmed case, said civil engineer Dan Gerrity of the authority and the University of Nevada Las Vegas.

Hampton Roads Sanitation District in southeastern Virginia started sampling for SARS-CoV-2 on March 11 “to look at trends and estimate what prevalence might look like,” said Jim Pletl, director of water quality for the utility.

For its inter-lab study, the Water Research Foundation will see if the analyses agree, hoping to come up with best practices that can guide nationwide implementation as soon as this fall

This is great because it can be used to find prevalence on a large scale level and detect discrepancies from regular testing that might arise from sampling error