Is the COVID wave peaking? The answer is in the sewers

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Steven Geringer/Yale University Photo

Annabelle Pan, a researcher in Jordan Peccia’s lab at Yale University, examines sludge samples.

Of all the methods for measuring the progress of the coronavirus pandemic, one has always been reliable: the amount of virus in wastewater.

Yale University researchers have been sampling wastewater treatment plants in Connecticut since the early stages of the pandemic, and the latest numbers from those tests have an official “cautiously optimistic” that the omicron wave has finally peaked. in the state.

The recent data provides a clear example of the valuable information that wastewater testing can provide to public health officials trying to deal with a pandemic that has dragged into its third year. But this type of analysis may not last long if Yale does not find additional funding for its work.

Until late last year, the state of Connecticut was paying Yale researchers to track the spread of COVID-19 at several large wastewater treatment plants that served more than a million people across the country. State.

These samples closely tracked the ebb and flow of the virus in many of the state’s most populous communities, including Bridgeport, Stamford, Norwich, Hartford, Waterbury, Danbury and New London.


But the state contract under which the work was performed ended in October 2021, and when it did, the public health data that was being collected was cut off in many places.

Yale was able to find private donations to continue wastewater sampling at one of its sites in New Haven for the first half of 2022. But those tests will also cease to exist this summer without additional financial support.

Max Reiss, a spokesperson for Governor Ned Lamont, said the data Yale was able to release between August 2020 and October 2021 has proven to be an “effective tool” in monitoring the spread of the virus in Connecticut. But the state chose not to renew the $768,045 testing contract last fall, he said, because the numbers Yale released weekly were seen as a secondary source of information that didn’t do that bolster data the state was already compiling from individual COVID tests.

In other parts of the country, however, epidemiologists and public health officials are now turning to sewage treatment plants as a more effective, long-term solution to monitoring the lingering spread of the deadly virus.

There have been a slew of researchers — many centered at universities across the country — who have been running lab tests on fecal samples taken from sewage treatment plants to track the pace of the virus.

Tests that these groups have carried out repeatedly have shown that samples taken from human waste can quickly and accurately detect spikes in coronavirus cases at the community level, even before people begin to show symptoms or to search. virus testing.

As a result, there is a growing effort at the federal level to expand the network of sewage treatment plants that are looking for the genetic markers of COVID-19, which are found more frequently in sewage as the number of infections in a community increases.

The U.S. Centers for Disease Control is now encouraging additional testing at sewage treatment plants across the country, and the agency is setting up a new website where data collected at those plants can be shared and analyzed. This effort is called a national wastewater monitoring system.

In response, states like New York are dramatically increasing the number of processing plants they have partnered with.

Jordan Peccia, a professor of environmental engineering at Yale University who helped lead wastewater testing in Connecticut, said samples taken from treatment plants during the early stages of the pandemic were widely used as a backup data source to confirm state testing numbers. were showing.

Since then, the science surrounding sewage testing “has matured rapidly,” Peccia said, and the techniques used have proven to be a reliable indicator of the prevalence of coronavirus in a given city.

At this point, Peccia said, samples collected from sewage treatment plants likely provide a more accurate representation of the pandemic than individual test results that are compiled by state health departments.

“I see an increased need for it now,” he said.

Collecting sewage samples, Peccia said, is preferable to nasal swabs and saliva testing when it comes to understanding community-wide trends. It detects spikes in the community that spread faster than testing at driving sites or sampling at hospitals.

It also captures a picture of everyone in a geographic region, not just people who choose to get tested because they have symptoms or need to be screened for their work. That’s important at this stage of the pandemic, when some people may have no symptoms of the virus or undergo home tests that aren’t reported in the daily testing figures.

“I’m not criticizing, but the information you get from the compiled tests is getting worse and worse,” Peccia said. “And that’s because the systems are under stress, and we’re doing all these home tests now. We’re not reporting it to anyone.”

“The stream of data coming into governments monitoring whether outbreaks are rising or falling is getting weaker and weaker as testing efforts become less and less scrutinized.”

That doesn’t mean individual COVID testing doesn’t have a role to play in the public health response. Individual nasal swabs and home testing kits are essential tools for telling an individual if they are infected, Peccia said. These tests inform people if they should self-isolate and take other precautions to stop the spread of the virus.

They simply aren’t the most effective way to monitor whether a city, county or state is experiencing a spike in COVID cases, Peccia argued.

“We can never completely replace the home testing kits or the testing device that we have,” Peccia added. “But sewage is probably a much better way to look at trends in a community. It’s a good thing to have whether the cases are high or low.”

Laboratories like Yale’s are also capable of sequencing sewage samples to track the most common coronavirus variants in a community at any given time.

Take sewage sampling in New Haven. Over the past month, Peccia and his team have been able to closely monitor the replacement of the delta variant with the omicron variant, which hit the state in late December and January. Omicron passed delta on Dec. 23, according to the data.

Relying on samples from centralized sewage plants could also be a more cost-effective way to monitor the virus long-term, Peccia said. Instead of paying for thousands of individual tests, public health officials could pay for a single sample every day that tracks the spread of the disease among hundreds of thousands of people.

“We really shouldn’t be testing in order to track cases,” Peccia explained. “It’s a very expensive proposition.”

When the Yale lab tests the New Haven sewage sample each day, it’s effectively testing more than 200,000 people for COVID-19 at a time, Peccia said. He catches everyone. Between the reagents needed to perform the tests and the lab workers, it can cost as little as $50 per sample, he estimated.

As part of its contract with the state, Peccia said the biggest cost was paying couriers to get the samples to their lab. In total, the state spent $768,045 in federal funding for Yale’s testing efforts.

Investments in this kind of work are still underway just across the border in New York, where authorities are now trying to set up a statewide “wastewater monitoring system” .

The New York Department of Health is currently working with researchers from Syracuse University and the State University of New York to solidify a testing network that includes at least one treatment plant in each of the 62 counties of the state.

David Larsen, environmental epidemiologist at Syracuse, said he expects the statewide testing push for treatment plants in New York will allow local health officials and the State to respond to the pandemic more accurately.

Data collected from factories could allow New York officials to identify communities with limited spread so local officials can safely end mask mandates and other precautionary measures, such as social distancing. social.

It could also allow state health officials to quickly set up more testing sites in areas where the virus is spreading quickly or target vaccination campaigns in communities most at risk.

“If we have a good understanding of which locations are high risk for transmission and which are not, then we can tailor our interventions to those locations,” Larsen said.

All of these things could be important as the virus continues to spread across most of the country.

“The virus is not going away,” Larsen said. “The virus will always be there. It will always be a threat. So if we’re here for the long haul, we need to build systems that support that.”

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