What is Wastewater COVID Testing, And How Does It Work?
Published By: Alex Gualt, Nov 28, 2020 -NNY360 Watertown Daily Times and Northern New York Newspapers
SYRACUSE — Testing has been one of the main tools used by local and state governments to combat the spread of the novel coronavirus, and the Syracuse-based company Quadrant Biosciences is at the cutting edge of test development.
Quadrant, a private research laboratory embedded in Upstate Medical University, has been working since March to develop a series of tests that can detect signs of the SARS-CoV-2 virus, which causes COVID-19.
“The virus sheds in the gut of the individual before the individual becomes symptomatic, or before the individual would test positive on a nasal or saliva swab,” he said. “From that, we’re able to test wastewater from the shedding, and pick up the presence of an infected person.”
Mr. Heslop said the Quadrant wastewater test is able to pick up one infected person in a population of about 10,000 people.
Quadrant’s COVID-19 research team is led by Dr. Quin Du, the company’s vice president of clinical research. Dr. Du was instrumental in developing the COVID-19 tests for Quadrant. According to her, in a sample of COVID-contaminated wastewater, there are living, dead and fragmented viruses. Once a sample is collected and taken back to the lab, the viruses are concentrated and the resulting sample is tested for genetic material that matches the SARS-CoV-2 virus.
Dr. Du and Mr. Heslop said wastewater testing is currently able to track if there is any sign of the coronavirus in a community, and can track changes in the amount over time, but they are not yet able to estimate how many people could have COVID-19 based off a sample.
“We can pick up one infection, but we can’t tell you if it’s one or five out of 10,000,” Mr. Heslop said.
Dr. Du said there are a number of factors that can have an effect on the concentration of the virus in a sample, based on how much water is flowing through the sewers, what other chemicals may be in the water and the temperature. She said the Quadrant team is currently working to find a way to estimate how many people may be infected based on wastewater test results.
“We are working on that right now actually, we just did some experiments where we had a known number put into the sewer system, and then at the end test and see how much of the virus we are able to detect,” she said.
Currently, Quadrant is partnering with more than 500 organizations and governments to test their wastewater systems for signs of COVID-19. Tests are currently being done weekly for dorm buildings on all SUNY campuses and a number of private colleges, including St. Lawrence University in Canton. City-wide wastewater testing is being done for a number of municipalities across the state as well, including Watertown and Syracuse.
Wastewater testing is only a part of the Quadrant testing regimen. Once a wastewater test comes back to show a presence of the SARS-CoV-2 virus, a second step of pooled testing comes in.
Quadrant has also developed a non-invasive saliva test for the SARS-CoV-2 virus, based on its existing Clarifi testing platform. According to peer-reviewed data, the Clarifi saliva test is the third-most sensitive COVID test available in the U.S., surpassing the tests developed by LabCorp, Boston Medical Center and the Center for Disease Control and Prevention by a significant margin.
That test serves as a second step in its testing regimen to be used when a college or local health department begins to see an increase in the viral load of its wastewater systems, or as a first-step surveillance testing system for places that do not use wastewater testing.
The Clarifi COVID-19 test, which has Emergency Use Authorization from the U.S. Food and Drug Administration, can be used for pooled or individual testing. With pooled testing, up to 25 people can submit saliva samples, which will be combined together and run in one test.
If a pooled test were to come back positive, each individual person who submitted a sample for that test would have to get a second, individual test to indicate who in the pooled group actually has the virus.
“The speed is much higher, and the cost is much lower, because you’re only doing one test, not 25,” Mr. Heslop said.
Both Mr. Heslop and Dr. Du said there’s much more work to be done during the coronavirus pandemic to understand the virus, the disease it causes and how best to combat it. Even if a vaccine is developed and distributed nationally, both Mr. Heslop and Dr. Du said there will be an ongoing need to test, contact trace and monitor cases until the vaccine has been given to a majority of people.
He said there are also applications for wastewater surveillance testing for other viruses, and Quadrant intends to continue studying those opportunities for the foreseeable future.
“On the COVID side, the pandemic, it’s easy to see that we’ll be on the subject for another six months to a year, minimum,” Mr. Heslop said. “On the viral side, loading and understanding, (Dr. Du) has a career ahead of her.”
Dr. Du said the severity of COVID-19 provided the motivation necessary for the scientific community to dive deep into these areas of viral research, and what scientists have learned could be applied to any number of other viral diseases.
“There’s no reason we can’t apply what we’ve learned to other diseases,” Dr. Du said, “and because of that, the scientific community and also the government, I think, are now more interested in using this mode of surveillance in the future.”