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Most of us choose not to think about what happens after we flush: Out of sight, out of mind.
But people who work in public health are paying close attention.
The state Department of Health and Human Services conducts weekly testing on untreated samples collected at 14 wastewater treatment plants around the state, analyzing them to detect COVID-19. The results, posted to the health department’s dashboard, can be used to monitor community transmission of the virus.
The public health lab looks for the level of virus in a sample, explained Ryan Tannian, chief of the bureau of infectious disease control at DHHS. “That correlates to what the viral burden is within the community that feeds into that wastewater,” he said.
Later this year, the state plans to expand the program to include testing for influenza and RSV, two other respiratory viruses expected to circulate this fall and winter, Tannian said.
Now that the COVID public health emergency has ended, wastewater sampling is playing an increasingly important role in monitoring the viruses that could make us sick this fall, health officials say.
While schools and nursing homes are required to report outbreaks of communicable diseases, Tannian said, health care providers are no longer required to report positive COVID cases to DHHS, though some continue to do so. Meanwhile, most people are using at-home tests if they suspect they may have the illness, and no one is collecting data about those results.
The statewide wastewater surveillance, which detects viruses shed by people with or without symptoms, can provide important clues to what’s happening in the wider community.
In recent weeks, some facilities around the state saw an increase in the numbers. That correlates with a national jump in both COVID cases and hospitalizations, Tannian said.
Meanwhile, cases of RSV (Respiratory Syncytial Virus), which is especially dangerous for the littlest kids, have been increasing in the Southeast lately, Tannian said. “It’s only a matter of time. Over the next few months we’ll start to see more RSV as it starts to move north and west,” he said.
At the epicenter
The wastewater monitoring program is an important tool for public health surveillance, Tannian said. “Unless providers are sending us that information, wastewater would be one of several ways to figure out: Is RSV here and is it spreading through our communities right now?” he said.
The public also can use the wastewater data published on the state dashboard (www.covid19.nh.gov) to make personal decisions about health, Tannian said. “If you know that RSV and influenza are in your community, you should have that conversation with your health care provider about ways you can protect yourself,” he said.
DHHS launched the COVID-19 surveillance program statewide in December last year, with 14 treatment facilities participating voluntarily. At the time, Patricia Tilley, director of the Division of Public Health Services, noted it had “the potential to provide additional and earlier insight about COVID-19 in our communities.”
Participating facilities are in Berlin, Dover, Durham, Hampton, Hanover, Keene, Manchester, Merrimack, Newmarket, Newport, Portsmouth (both the Pease and Peirce Island facilities), Plymouth and Sunapee.
Monitoring wastewater for a novel coronavirus seems a radical departure for the industry.
But Frederick McNeill, chief engineer in Manchester’s Environmental Protection Division, doesn’t see it that way. “On the contrary, our whole existence is a public health mission,” he said.
“Six hundred thousand people take their drinking water out of the Merrimack River downstream from us,” he said. “If we don’t do our job, we’re like Flint, Michigan, or Jackson, Mississippi,” he said, citing two cities with infamous water contamination crises in recent years.
The Manchester treatment plant handles wastewater from households in Manchester, Goffstown, Bedford and Londonderry, McNeill said. “We’re really the epicenter for New Hampshire business and commerce, and population too,” he said.
In his view, “We are really the front line of environmental stewardship,” he said. “So this dovetails with our mission perfectly.”
Tannian from DHHS agrees. “High quality public sanitation systems are key and essential to public health,” he said. “We don’t worry about diseases like typhoid and cholera anymore in 21st-century America, because we have wastewater treatment plants, and we check what’s in our public water supply.”
The monitoring project came out of research done at the University of New Hampshire, where Paula Mouser, a professor of environmental engineering, focuses on solving environmental problems that involve contamination and public health risks.
Early in the COVID-19 pandemic, Mouser and a colleague proposed developing a method to extract and quantify the SARS-CoV-2 virus from wastewater samples. (Severe acute respiratory syndrome coronavirus 2 is the scientific name of the virus first reported in 2019, which soon became shortened to COVID-19.)
As the health crisis deepened, scientists and engineers around the country were working on the problem and sharing their methods with unprecedented cooperation, Mouser said in an interview. “We were able to really quickly test out some different methods and get them working,” she said.
Her team identified 30 or so manholes around residence halls on the UNH campus to collect samples. Early on, she said, “We started to see high viral numbers at times when we knew that there was a lot of socialization going on.”
As the pandemic continued, Mouser said, “Any time there was a new variant that started to come into our community, we could really see an uptick in the numbers, especially if that variant was more spreadable.”
Her team worked with the university’s COVID lab, which was constantly testing students and faculty on campus.
“We saw very good correlation,” she said. “And oftentimes, we could detect it in the wastewater a day or two before they started detecting it in individuals.
“It was a really good indicator of where we could expect new infections.”
Last year, UNH partnered with DHHS to set up the statewide monitoring program, with funding from the Centers for Disease Control and Prevention, which launched a national surveillance system in 2020. UNH continued doing the actual testing for a time, but the state public health lab took that over about a year ago.
The surveillance program does miss populations in rural areas of the state that rely on septic systems instead of community treatment facilities, Mouser said.
But she said it remains an “excellent tool” to get a sense of community transmission, she said.
“It’s a nonbiased approach,” she said. “We’re looking at the community as a whole.
“Everybody has to use the toilet.”
Where COVID is
After a lull during the summer, the surveillance program began detecting increases in COVID-19 viral levels in mid-August at some New Hampshire facilities.
At the Durham wastewater treatment plant, the highest spike over the past year was recorded on Aug. 26. That coincided with move-in weekend for the University of New Hampshire.
That makes sense, Tannian said. “One hypothesis is that it coincides with the time that all the college students are returning to school, moving back in, starting class,” he said.
But it will take a few more years to prove that theory, he said. “Where (the science of) wastewater surveillance is still new and evolving, we still just need more data to answer those questions,” he said.
Mouser cautioned against blaming UNH students for the rise in Durham’s viral levels in August. She said she noticed the number of COVID cases in town had been going up since early August.
It’s likely more a function of how many more people were in Durham around that time, the families coming to town with returning students, Mouser said. “It’s an influx of population that hasn’t been there for a while,” she said. “We just have more people.”
The water reclamation facility in Hanover — home of Dartmouth College — currently shows the highest viral counts in the state.
Detection plus prevention
As these viruses begin circulating this fall and winter, Tannian from DHHS offered advice for the general public: “Get your flu shot, and talk to your health care provider about the updated COVID-19 vaccine. Talk to your health care provider about the RSV vaccine.
“Have those conversations with your health care provider to protect yourself.”
If someone is traveling to another state, it makes sense to check on the rates of community transmission for COVID, flu or RSV there, he said. “It can help guide their decision on what protections they want to take,” he said.
Don’t forget those other commonsense ways to avoid getting colds and other viruses that we all learned in those early days of the pandemic, he said.
“Wash your hands frequently. Cover your nose and mouth when you sneeze or cough,” he said. “And stay home when you’re sick.”
Mouser said she’s proud of the work her UNH team did in advancing public health monitoring in New Hampshire.
“We feel like we’ve served our community well,” she said. “And as an academic institution, we’re looking forward, and trying to use the information that we learned through the COVID-19 pandemic to be able to develop approaches for the next pandemic.
“So that we’re prepared.”