Wastewater samples show COVID levels falling in New Haven area
The latest wave of COVID-19, driven by the contagious BA.2 and BA.2.12.1 subvariants, is showing signs of retreating, with falling levels of the disease being detected in wastewater.
Yale University researchers collecting samples from a New Haven water treatment facility found substantially fewer incidences of the virus in recent samples than were recorded a month ago. As of June 6, there were about 30 cases per 100,000 people in the New Haven area detected, down from about 60 cases per 100,000 people in mid-May.
The data mirror trends captured in state testing efforts. Connecticut’s seven-day rolling positivity rate fell to 7.5% on Monday, down from a high of 14% a month ago.
“It’s been going down for at least the last 20 days,” said Jordan Peccia, a professor of environmental engineering at Yale who leads the wastewater testing there. “If there’s one thing we know, it’s that wastewater is not wrong. We have been comparing it with all kinds of information on hospitalizations, on cases, etc., and it always matches nicely.”
“Historically, summers tend to be our lowest time of COVID rates, and winter is our highest,” added Dr. Manisha Juthani, the state’s public health commissioner. “We anticipate that similar trends will continue but remain vigilant for the emergence of new variants with different patterns of transmission.”
With the rise of rapid home testing and fewer people taking PCR tests that fuel state data on positivity, wastewater detection has become increasingly important in tracking COVID trends and predicting outbreaks.
Up until late last year, the state was paying Yale researchers to track the spread of COVID through several large wastewater treatment plants that served more than 1 million people in the state. Those samples closely traced the ebb and flow of the virus within many of the state’s most populated communities, including Bridgeport, Stamford, Norwich, Hartford, Waterbury, Danbury and New London.
But the state contract under which that work was performed ended in October 2021, and when it did, the public health data that was being collected was cut off in many locations.
Yale currently tests samples solely from the East Shore Water Pollution Abatement Facility, which serves New Haven, Hamden, East Haven and parts of Woodbridge. A private donor, Jonathan Rothberg, has funded the Yale lab’s work since the state’s support ended.
For now, state officials have no immediate plans to resume funding the Yale wastewater project. They are encouraging towns to participate in a new effort by the Centers for Disease Control and Prevention, which allows officials to contribute data from sewage treatment plants. The data are shared and analyzed on a CDC website.
So far, 11 communities have signed on to the program — three in New London County, one in Windham County, two in New Haven County and five in Fairfield County. But there is no data displayed for two of the sites, and others have not consistently reported COVID levels.
“The Yale information is incredibly helpful and informative. But when we started working with Yale, there was no infrastructure from the CDC at all when it came to this information, and now it does exist,” said Max Reiss, a spokesman for Governor Ned Lamont. “Obviously, the participation may not be at a significantly denser high level. However, getting different snapshots around the state definitely provides an informative perspective regarding what the virus is doing in various places.”
“We continue to work with different municipalities to encourage other areas to get as broad a view of the state as necessary,” added Juthani. “Because the CDC is funding this program robustly and allowing for as many municipalities at this time that we want to enroll, we are investing our efforts in getting towns to participate in this.”
Some other states have stepped up their wastewater efforts locally. In New York, Governor Kathy Hochul announced late last year that the state would be partnering with Syracuse University to continue its wastewater analysis. At least 20 counties have participated in the wastewater surveillance.
“Wastewater surveillance can provide up to three to five days’ early warning that COVID-19 cases are increasing or decreasing in a community, and studies have shown that it can be used to detect variants of the virus through sequencing wastewater samples, once identified,” Hochul said in a news release. “We’re learning new things about the COVID-19 virus every day, and in order to stay ahead of it, we’ve had to adopt new and innovative strategies for prevention and detection.”
Monitoring wastewater is important even during lulls in coronavirus cases, Peccia said, because there are clues for when the next wave may be starting. The Yale lab has been tracking wastewater since March 2020.
“There are times when everybody cares about COVID, and there are times when nobody cares about COVID. We’re entering into one of those nobody-cares-about-COVID times,” he said. “But the one thing we know is it'll probably be back. It’ll likely be [increasing] in the fall.
“I’m guessing in July and August, nobody’s going to look at our results. Few people are going to be testing in the state; we’re going to be happy. Then a variant or something is going to occur, outbreaks are going to occur, and people are going to care about it again. You need this information to keep being vigilant when nobody’s watching it. You get the early indication of when it’s coming back, because it’s so hard and expensive to ramp up these testing programs.”
With the help of the private donor, Yale will continue its surveillance through at least next June. The lab plans to launch a new website with its wastewater updates later this summer.
“If COVID goes away or gets really low, that’s when we need wastewater — some level of continued surveillance to make sure it doesn’t come back, or if it comes back, we have early warning for it,” Peccia said. “That’s where wastewater really shines.”
Staff writer Andrew Brown contributed to this story.