Wastewater surveillance yields crucial COVID-19 data, but also raises privacy concerns: scientists

During the COVID-19 pandemic, wastewater monitoring and analysis became an important tool in monitoring and measuring the amount of viruses in communities.

But some experts caution that the data collected from these studies can also lead to privacy concerns, especially since samples are often collected from public sources without individual consent.

“Bioethics, which underpin what healthcare providers do, have traditionally been based on ‘do no harm’ — and the idea of ​​informed consent,” said Steve Hrudey, professor emeritus of the University of Alberta’s division of laboratory medicine and pathology. . “Well, informed consent really isn’t possible for these kinds of techniques.”

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

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

Those guidelines suggest that surveillance programs should follow four main goals: working for the common good, justice, respect for individuals, and good governance.

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

The poop doesn’t lie

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

“If you lose it right away, within days of being infected, that information is already flushed down the toilet.” [and] travel 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 company Biobot Analytics.

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

Ghaeli, who studied in Waterloo, Ontario and Montreal before founding Biobot in the US, said the technology used by her company can currently detect a positive case in a sample of a population of 6,500 people.

That data has become increasingly important as provinces and territories scaled back access to PCR testing in the second half of 2021, especially as the Delta and later Omicron waves saw significant spikes in reported and suspected positives.

Experts like Ghaeli say that while the data can be very accurate, there is no way to identify a person, even if they detect a single positive case.

Your poo has no identifying information, as it were, such as a fingerprint.

“If we get a positive test, there’s no way we know who it’s coming from. You know, it’s like saying, ‘Oh, we have so many cars on the 401 today.’ You have no idea who is driving those cars,” said Kim Gilbride, a professor and molecular microbiologist at Toronto Metropolitan University’s Gilbride Lab for wastewater monitoring.

A pellet derived from wastewater material is seen in the Gilbride Lab at Toronto Metropolitan University. (Peter Mitton/CBC)

Lifespan of sludge, poop granules

Gilbride’s lab analyzes sewage samples supplied from all over the Greater Toronto Area: some from hospitals, long-term care facilities, while others come from the Humber Wastewater Treatment Plant.

Those bottles are usually filled with cloudy water, but some are more opaque and labeled “sludge.”

“If you open one of those — yes, you have to duck for cover,” says Babneet Channa, a research assistant who helps process the samples.

Nora Dannah is a postdoctoral researcher who works at the Gilbride Lab for Wastewater Monitoring at Toronto Metropolitan University. (Peter Mitton/CBC)

Channa and another assistant Matthew Santilli usually work with equipment equipped with a fume hood to vent those odors. They put the samples in test tubes that spin in a centrifuge — turning the sludge into a relatively inert pea-sized pellet for analysis.

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

Data can help or harm people in neighborhoods: Hrudey

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

With enough limited data, public health officials in a neighborhood can be deployed to prevent outbreaks from spreading further. But it can also be misused to stigmatize the people who live there — or worse, Hrudey warned.

Nor is it purely theoretical, he said.

There have been cases in Hong Kong and Singapore where wastewater monitoring has been used in apartment buildings and then authorities have tracked positive samples from individual apartments, Hrudey said.

“The 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 that there is a public health reason for that, but you can see that there may be a slippery slope.”

Research assistant Babneet Channa processes bottled wastewater samples in Toronto Metropolitan University’s Gilbride Lab. He usually works under a fume hood, which will dissipate the odor. (Peter Mitton/CBC)

Hrudey also said he had seen a draft research proposal that suggested it might be possible to map the infection rates from COVID or other traceable diseases in a neighborhood to the block.

“It was so detailed you could almost identify the street addresses,” he said.

However, he stressed that the proposal was theoretical – just a representation of what might be possible – and he is not aware that anyone in Canada has attempted this or gained access to private citizens’ data to use it. .

“Health authorities, at least in Alberta and I suspect in most provinces, are bound by very strict privacy laws regarding individually identifiable medical records,” he wrote. The Sunday Magazine 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 possible future applications that almost read like science fiction: wastewater monitoring robots that can crawl through residential pipes, take samples from a single street or even a detached 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 said.

“I think we’ll be in a different place in a year or so because it’s absolutely necessary for us to, I think, talk through these tough questions and resolve them,” she said.


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

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