Philly’s wastewater testing for COVID is up and running, but city has yet to share data

Philadelphia officials have begun relying on wastewater testing to track COVID-19 in the city, but still aren’t sharing the information with the public.

Wastewater testing entails analyzing the genetic material in the poop of people with the virus and is among the most reliable ways to track COVID infections. Philadelphia Health Commissioner Cheryl Bettigole said Friday that the health department’s wastewater testing program was “shaping the department’s understanding of the state of the pandemic.” Her comments contradict health department staff’s previous description of the wastewater management program to The Inquirer. Days earlier, the health department said the information was not being used for COVID surveillance or policy-making.

“We look at that data regularly,” said Cheryl Bettigole, the city health commissioner. “I get it once a week.”

Earlier in the week, in response to questions for an Inquirer story that published online Thursday, department spokesperson Matt Rankin said that “evaluation of the COVID wastewater surveillance is ongoing and currently does not inform our surveillance/policy.”

After that story published, department officials said they had misinterpreted reporters’ questions. The health department meant there had been no changes in the city’s COVID-related safety policies prompted by results from wastewater testing, Bettigole said.

Wastewater testing results, along with data from COVID tests and hospitalizations, has been included in Bettigole’s weekly briefings on the pandemic since earlier this summer, health officials said.

Those COVID metrics all point to the same conclusion: “We are seeing a slight gradual decline in COVID cases,” Bettigole said.

That same data could offer residents the most accurate look at local COVID trends, but has not been shared with the public or the Centers for Disease Control and Prevention. The department wants to be sure it can fill out all the fields requested by the CDC before sharing data with the federal health agency, Rankin said.

Experts argue, though, that even an imperfect testing and data program would be a valuable tool for the public — especially with fewer and fewer people reporting at-home test results.

“Just because we don’t have the best shouldn’t be enough to keep us from starting,” said Charles Haas, a professor of environmental engineering at Drexel University. “This is the last tool available to get a broad picture of what’s going on in the community.”

Some 1,000 jurisdictions across the country, including Montgomery County, are increasingly relying on the stuff we flush down the toilet to monitor COVID. Other cities, including Houston, are also using the technology to track viruses such as monkeypox or polio.

Wastewater testing simply requires the public to use the bathroom to be effective.

The CDC data compiled from 1,155 wastewater sampling sites across the country give perhaps the most accurate picture of COVID’s spread.

Philadelphia launched a wastewater testing pilot program in 2020, but it was discontinued. The city resumed wastewater collection in January and by May was gathering samples that program leaders felt were reliable.

» READ MORE: The clues are in the poop: COVID-19 sewage testing is coming to Philly

Still, health officials are withholding data as they work through processing delays. They’ve also expressed methodological concerns with their collection and interpretation of their data.

For instance, they are trying to update the tests run on wastewater samples to capture the latest variants. Sampling identified when Omicron BA.5 became the predominant variant detected in wastewater and when that shifted from BA.2, Rankin said Friday.

The CDC is currently gathering wastewater data from 983 sites, but Philadelphia isn’t one of them right now. The city is finalizing efforts to share data with the federal agency, said Rankin.

The department is also concerned that wastewater data can’t predict the number of COVID cases in a community.

“Setting up surveillance systems like this and looking for opportunities to improve them is challenging,” said Rankin.

But experts criticized health officials for withholding useful data in a fruitless effort to perfect science in an emerging field.

“Is this what they think is a reasonable and timely response in a pandemic scenario?” said Scott Olesen, an epidemiologist at the wastewater testing company Biobot Analytics, which publishes its data online.

Olesen said he doubts wastewater testing will ever provide an accurate measure of case counts because the amount of virus a sick person sheds in the wastewater is highly variable.

Wastewater’s value is as a tool for identifying trends, Haas said.

“If you see a spike of what’s coming in the wastewater, it’s going to be indicative that you’re going to have a rise in cases,” Haas said.

The department anticipated adding wastewater data to its online COVID dashboard, but the urgency of sharing data about the recent monkeypox outbreak has caused delays.

While Philadelphia’s health department works out the kinks of tracking COVID through wastewater testing, other cities, including Harrisburg and New York City, are moving forward with programs to test wastewater for other emerging public health threats, such as monkeypox and polio.

This could be a particularly valuable use for wastewater testing programs, since testing for monkeypox has been hard to access, likely resulting in an undercount of cases.

“The science behind monkeypox testing in wastewater is not settled at all,” Rankin said.

Scientists at Verily Life Sciences, Stanford University, and Emory University are testing for monkeypox in wastewater across the country, including in Harrisburg, as part of a national initiative called WastewaterSCAN. The initiative posts results online and shares them with the CDC. Philadelphia is not part of the project.

The wastewater program is “entirely funded by CDC,” Rankin said. “We felt it best to await their guidance for anything related to monkeypox testing,” Rankin said.

Polio testing — in wastewater and otherwise — is handled by the CDC, Rankin said, and the federal funding that supports the wastewater testing program currently requires the technology be focused on COVID. Philadelphia has not identified any polio cases this summer.

» READ MORE: Philly health department’s new lab a key resource for tracking COVID

Testing for other diseases, though, isn’t a difficult adjustment, Haas said.

“Once you’ve got the sewer sample and you’re bringing the sample in to test it for new organisms, that level of effort is minor,” he said. “Once you have an oven in your house and you’ve been cooking cakes, you can cook a beef roast. You just need a different temperature and time.”

Haas reached out to Bettigole when she began her term and offered to help set up a wastewater testing program. He didn’t hear back, he said.

On Friday, Bettigole said she didn’t recall hearing from Haas. Regardless, the city didn’t want to switch partnerships mid-project, Rankin said.

Temple and Michigan State University currently test Philadelphia’s wastewater, though the city eventually plans to run the program without help. The city debuted this month its own genetic sequencing lab, which can test COVID samples to identify variants from nasal swabs and can be used to evaluate other kinds of bacteria and viruses, but that lab has not yet been used to process wastewater test samples.

Building internal testing capacity is worthwhile, Olesen said, but the trade-off is withholding valuable data.

The city’s program, Olesen said, “doesn’t seem to have served the citizens of Philadelphia very well, at this point in time.”