NEW HAVEN — Sewage may help guide us through the coronavirus pandemic, or at least tell us whether COVID-19 will spike again in the New Haven area.

Researchers from Yale University and the Connecticut Agricultural Experiment Station analyzed solid waste from the East Shore Water Pollution Abatement Facility between March 19 and May 1 and found the amount of coronavirus, SARS-CoV-2, correlated with testing totals and hospitalizations.

“It was basically a leading indicator of seven days when it came to testing,” said Douglas Brackney, an associate scientist in the experiment station’s Department of Environmental Sciences and a co-author of the study. He said the amount of virus found in the stool correlated with hospitalizations three days later.

“My guess is that as testing has increased that will probably be less than seven,” he said Wednesday.

“The hope is that this can be used as a surveillance method,” Brackney said. “A lot of people are concerned about there being a second wave … once these social-distancing restrictions are lifted. … We can be constantly testing the sewage sludge.”

According to the paper, posted on medRxiv.org, “Our study could have substantial policy implications. Jurisdictions can use primary sludge SARS-CoV-2 concentrations to preempt community outbreak dynamics or provide an additional basis for easing restrictions, especially when there are limitations in clinical testing.”

Jordan Peccia, professor of environmental engineering at the Yale School of Engineering and Applied Sciences and a co-author of the paper, said the testing is cost effective and can be useful in tracking the spread of the virus.

The virus’ RNA is extracted by first concentrating the sludge. “Then you have to get the viral RNA popped open, out and efficiently extracted into very small quantity — about 51 millionths of a liter. And then there’s an enzymatic process to amplify the sample. The process takes a while,” Peccia said.

Peccia said he and his team hope to eventually scale up the project and expand it to other parts of the state. But there is a practical obstacle in the way: research funds are difficult to come by. But still he and his team believe there is a need for this additional method of testing.

“We would think of this as something that augments testing programs and public health measures already in place,” Peccia said. “Testing, of course, is really important. An individual needs to know whether he’s sick or not. That’s a fundamentally important thing. … But I think that we can get additional valuable information from wastewater testing.”

“Obviously, if you take this out to other catchment areas you can cover the whole state pretty easily,” Brackney said. “Personally, I think it would be a very smart thing for governments to enact.”

Dr. Thomas Balcezak, chief clinical officer at Yale New Haven Health and Yale School of Medicine, said researchers have not heard of any cases in which COVID-19 been spread by stool.

“I don’t think it has transmission implications. I do think it has implications for how we could look and survey across the country about what is the burden of coronavirus in our communities,” Balcezak said Wednesday during a weekly online press conference. “By sampling that, and then using that to backtrack if a certain concentration is in the wastewater, what would be the percent of that population that would be infected?

“It is a curious study and I think it is interesting, but I don’t think it is a source of concern [for] our workers at the wastewater treatment plants and I don’t think it is a source of concern as a mode of transmission,” he said.

The treatment plant, situated on the east side of New Haven Harbor, takes in sewage from New Haven, East Haven, Hamden and Woodbridge. About 40 million gallons of sewage are treated per day at the plant.

Connecticut Media Group