By Emmett Chan
The covid-19 pandemic has brought on a number of unexpected developments, but the most surprising among them may be the emergence of testing wastewater for diseases.
While some cities used wastewater to track traces of polio in the 20th century, the pandemic has made sewage sampling a more widespread practice—with the potential to become an integral part of how society monitors health.
According to The Economist, “The first team to publish results from wastewater testing for covid-19 was based at KWR, a water-research institute in the Netherlands. Researchers discovered early in the pandemic that about half of infected people shed sars-cov-2 in their faeces.”
A report by the Dutch researchers explains that they began by testing wastewater at several cities and the Amsterdam Airport Schiphol in February, finding covid-19 virus RNA that correlated with reported covid-19 cases in the cities and the airport.
The research team concluded “that sewage surveillance could be a sensitive tool to monitor the circulation of the virus in the population.”
Since then, academics in over 70 countries have established improvised programs to detect traces of covid-19 in wastewater.
These programs vary in the populations they cover, from localized hubs like universities, or entire countries like the Netherlands, where researchers were monitoring every sewage treatment plant in the country by September 2020.
Regardless of the program’s size, wastewater screening remains a powerful tool: “Researchers reckon a single infectious case of covid-19 can be detected amid the waste of up to 14,000 people. Testing the effluent of an entire population is much cheaper than individually screening each resident, and can often spot cases earlier.”
In practice, these statements held up: “Wastewater analysis proved capable of spotting waves of infections one to two weeks before conventional, nasal-swab testing. Countries with lower rates of conventional testing, such as Malawi, got up to a month’s notice.”
Although wastewater data is available online for many countries, their technology and infrastructure are inconsistent and underdeveloped across the numerous wastewater surveillance programs.
“Collecting, testing and reporting procedures must be standardized,” The Economist urges, to allow comparisons between different places. Many existing procedures are strikingly low-tech. Tampons are often used as a tool to soak up water for testing, for example.”
While covid-19 surveillance is the primary function of wastewater testing, scientists are excited for the myriad of possible uses sewage sampling could offer.
The most obvious application would be to screen for other diseases, but the potential of wastewater testing is much more far-reaching.
Biobot Analytics, the first company in the world to profit from sewage health data, was the first group in the U.S. to use sewage data to track the spread of covid-19.
Before the pandemic, Biobot focused on gathering data on opioid usage, which was paused to focus on covid-19. Now, the company is resuming its efforts with increased technology and resources:
“Biobot’s High Risk Substance platform provides unbiased, naturally anonymized data on community use of fentanyl, methamphetamine, cocaine, and nicotine. Monthly reports help public health officials establish a baseline level of substance use in their community, identify which substances are most commonly used, determine seasonality of use, and better measure evidence-based public health interventions.
“Others want to monitor health in a broader sense,” The Economist explains, laying out a range of possible applications for wastewater testing:
“In 2019 researchers at Arizona State University published a wastewater study that analyzed levels of phytoestrogens, chemicals found in plant-based foods. It suggested that sewage monitoring could be used to keep track of a nation’s eating habits. Kando has a list of over 500 biomarkers potentially detectable in wastewater. The company hopes that levels of one of these, serotonin, might yield interesting data on depression. In Australia, researchers use sewage to keep track of nicotine and alcohol consumption.”
Despite the already widespread success that wastewater testing has had with monitoring covid-19 and the countless possibilities that this technology has to offer, KWR’s first covid-19 testing program demonstrates that sewage sampling programs must start small and expand later. A relevant and increasingly common example is wastewater testing at universities like UCLA.
Universities serve as hubs not only for students, but for the surrounding community—faculty, employees and local residents who may visit the campus.
This makes university campuses—especially ones with the population and resources of UCLA—ideal communities to implement a wastewater testing program.
Universities are communities that can serve as test runs for wastewater testing programs, but the concept of starting these programs at a small scale and expanding them later was demonstrated within UCLA itself.
In 2020, UCLA’s program started only at two housing units, De Neve and Sunset Village, and later expanded to include all on-campus residence buildings. These buildings, which include restrooms, are all under one institution, streamlining coordination of wastewater surveillance.
With this data, trends in COVID infection can be forecasted and analyzed for the UCLA community, as dorming students will frequently come into contact with students, faculty, employees and others living off-campus.
Unlike other protocols, wastewater testing will likely remain relatively constant.
Though UCLA is easing up on covid-19 protocols, future spikes in covid-19 cases may lead to the reinstatement of requirements such as mandatory indoor masking—as occurred during the 2021–2022 school year.
But even if protocols remain the same throughout the 2022–2023 school year, covid-19 testing in general will still be encouraged, and will likely remain obligatory when individuals are at high risk of infection—when they exhibit symptoms, have been exposed to positive cases, or if covid-19 has been detected in their residence hall’s wastewater.
UCLA should expand its wastewater testing program to all buildings on campus, but concerns like logistics are valid reasons for the program’s currently limited scope—most buildings are not as interconnected as The Hill, where the dorms are located.
As promising as wastewater testing is, U.S. citizens—including university students—should be willing to consider how these programs factor into discussions on surveillance and privacy.
The Economist explains that “in Singapore and Hong Kong it has proved possible to monitor waste from individual apartment buildings and hospitals. In both places, these techniques—coupled with shoe-leather epidemiology—allowed authorities to identify individual covid-19 patients from within individual blocks of flats.”
With such precision, and the ever-increasing range of data that can be detected in wastewater, the public has good reason to be wary of the risk of legitimizing this powerful tool.
“Popular support will be harder to secure if people worry that their data might be widely shared,” warns The Economist. “Testing bodies should therefore be open about the extent of their capabilities, and exactly how data will be used. They should also consult with the people being monitored, so that something approaching informed consent can be obtained.”
Still, covid-19 has pushed scientists to draw on many resources to form creative and important solutions—even if they use something as unsavory as sewage.
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