Wastewater monitoring provides crucial COVID data, but also poses privacy concerns: scientists

Throughout the COVID-19 pandemic, wastewater monitoring and testing has become a key tool to monitor and measure the amount of virus in communities.

But some experts warn that data collected from such studies could also lead to privacy issues, particularly because samples are often collected from public sources without individual consent.

“Bioethics, which sort of underpins what healthcare providers do, has always been based on ‘do no harm’ – and the idea of ​​informed consent,” said Steve Hrudey, professor emeritus of the Department of Laboratory Medicine and Laboratory Medicine at the University of Alberta. pathology. “Well, informed consent is really not possible for this kind of technique.”

Hrudey is chair of the National Research Advisory Group for the COVID-19 Wastewater Coalition, a nonprofit group founded in the spring of 2020 that helps coordinate and share information about wastewater monitoring efforts across the country.

A 2021 article co-authored by Hrudey and six other researchers recommended that wastewater surveillance programs for COVID-19 follow a list of 17 guidelines presented by the World Health Organization for ethical public health surveillance.

These guidelines suggest that surveillance programs should pursue four main objectives: working for the common good, equity, respect for people and good governance.

“The arguments for maximizing the potential of this approach are compelling, but the benefits of wastewater monitoring must clearly outweigh the ethical risks to the community,” the paper says.

poo doesn’t lie

Humans can eliminate the genetic material of the SARS-CoV-2 virus in the form of RNA. Sometimes the virus can be detected in human sewage samples before someone shows symptoms of the disease.

“If you lose it right away, a few days after being infected, that information is already flushed down the toilet [and] traveling to your wastewater treatment plant where it is collected and analyzed by, you know, us or someone like us,” said Newsha Ghaeli, co-founder of wastewater epidemiology firm Biobot Analytics.

Newsha Ghaeli is co-founder of Biobot Analytics, an American company testing wastewater for COVID-19. (Biobot analysis)

Ghaeli, who studied in Waterloo, Ontario, and Montreal before co-founding Biobot in the United States, said the technology used by his company can currently detect a positive case in a sample from a population of 6,500 people.

This data has become increasingly important as provinces and territories reduced access to PCR testing during the second half of 2021, particularly when the Delta and later Omicron waves experienced significant spikes in reported and suspected positive cases.

Experts like Ghaeli say that while the data can be very precise, there is no way to identify an individual even if it detects a single positive case.

Your poo has no identifying information like a fingerprint, so to speak.

“When we get a positive test, we don’t know who it’s from. You know, it’s like saying, ‘Oh, we have so many cars on the 401 today. You have no idea who’s driving these cars,” said Kim Gilbride, a professor and molecular microbiologist at Metropolitan University of Toronto’s Gilbride Laboratory for Wastewater Monitoring.

A pellet derived from sewage materials is seen at Metropolitan University of Toronto’s Gilbride Laboratory. (Peter Mitton/CBC)

Slime Life, Poop Pellets

Gilbride’s lab analyzes sewage samples from across the Greater Toronto Area: some from hospitals, long-term care homes, while others come from the sewage treatment plant in Humber.

These bottles are mostly filled with cloudy water, but some of them are more opaque and labeled “sludge”.

“When you open one, yes, you have to take cover,” said Babneet Channa, a research assistant who helps process the samples.

Nora Dannah is a postdoctoral researcher working at the Gilbride Lab for wastewater monitoring at Metropolitan University of Toronto. (Peter Mitton/CBC)

Channa and another assistant, Matthew Santilli, mainly work with equipment equipped with a fume hood to evacuate these odors. They put the samples in test tubes that spin inside a centrifuge – turning the slurry into a relatively inert pea-sized pellet for analysis.

“It’s anonymous. We don’t really go after people and say, ‘This is you,’ you know, or ‘This is your house,'” said Nora Dannah, a postdoctoral researcher who also works in the laboratory.

Data could help or hurt neighborhood residents: Hrudey

That’s not enough to allay the concerns of Hrudey, who says “you can focus on very small areas” if samples are identified and collected from specific sewer systems in a city.

With narrow enough data, public health officials could deploy to a neighborhood to prevent outbreaks from spreading further. But it could also be misused to stigmatize the people who live there – or worse, Hrudey warned.

It’s not purely theoretical either, he says.

There have been cases in Hong Kong and Singapore where sewage monitoring was used in apartment buildings and then authorities found positive samples in individual apartments, Hrudey said.

“Authorities showed up and said, ‘Well, you know, you have a case here and you need to be tested,'” he said.

“Now you can argue there’s a public health rationale for this. But you can see there’s a possible slippery slope.”

Research assistant Babneet Channa handles bottles of wastewater samples at Metropolitan University of Toronto’s Gilbride Laboratory. He mainly works under an extractor hood, which drives out the smell. (Peter Mitton/CBC)

Hrudey also said he had seen a draft research proposal that suggested it might be possible to trace a neighborhood’s infection rates from COVID or other traceable illnesses back to the block.

“It was detailed enough that you could almost identify the addresses,” he said.

He stressed, however, that the proposal was theoretical – presenting only what might be possible – and is not aware that anyone in Canada has attempted this or obtained access to private citizen data to use it.

“Health authorities are bound, at least in Alberta and I suspect in most provinces, by very strict privacy legislation regarding individually identifiable health records,” he wrote to The Sunday Review in a follow-up email.

He is not alone in raising these concerns.

A 2021 article in the European Journal of Law and Technology, by Dutch scientist Bart van der Sloot, posits potential future uses that sound almost like science fiction: sewage monitoring robots that could crawl through residential pipes , take samples from a single street or even a single house.

Ghaeli agrees that a more definitive ethical foundation needs to be established for how wastewater monitoring is used – and sooner rather than later. But we’re not there yet, she says.

“I think about a year from now we’ll be in a different place, because it’s absolutely necessary for us, I think, to talk and work through these difficult issues,” she said.


With files by Peter Mitton. Radio segment produced by Peter Mitton.

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