With diagnostic testing capacity continuing to be strained almost everywhere affected by COVID-19, sewage may offer another way to track the spread of the virus that causes the disease.
In the US, there are currently two main research efforts looking into how well SARS-CoV-2, the virus that causes COVID-19, can be detected and monitored in municipal wastewater.
Funded by a $200,000 National Science Foundation grant, a group from the University of Michigan (U-M) and Stanford University is exploring whether the novel coronavirus can be detected in wastewater before it’s known to be in a community. They are also hoping to learn more about what happens to the virus after it is shed from human hosts.
Also looking to track the virus through wastewater, Biobot Analytics, a wastewater epidemiology company that got its start at MIT, is partnering with Harvard University and Brigham and Women's Hospital in Boston, according to a report by Popular Mechanics.
The advantage of testing wastewater is that it allows researchers to test many people at once, rather than individually, and it’s not as susceptible to measurement bias, said Nasa Sinnott-Armstrong, a doctoral student at Stanford working on the project, in a press release.
“We could identify areas with rapidly increasing cases as a warning system to the health care system,” Sinnott-Armstrong said. “Finally, these numbers can help epidemiologists model the trajectory of the pandemic with far less testing burden on our health care system.”
On the other side of the Atlantic, scientists at UK-based Cranfield University are working on a rapid test to detect the virus in municipal wastewater. They agree that such monitoring could provide an early warning about the spread of the illness, allowing authorities to institute transmission prevention measures before it’s too late.
“In the case of asymptomatic infections in the community or when people are not sure whether they are infected or not, real-time community sewage detection through paper analytical devices could determine whether there are COVID-19 carriers in an area to enable rapid screening, quarantine, and prevention,” said Dr. Zhugen Yang, lecturer in sensor technology at Cranfield Water Science Institute.
Efforts exploring wastewater as a COVID-19 tracking tool began following a study by Chinese researchers showing that live SARS-CoV-2 can be detected in the feces of infected patients. Research by the Netherlands’ National Institute for Public Health and the Environment (RIVM) also found COVID-19 in Dutch wastewater.
“Research indicates that monitoring wastewater is a good strategy for detecting whether specific viral infections are present in a population,” said the institute in a press release, adding that RIVM has used molecular methods before to detect the measles virus, poliovirus, antibiotic-resistant bacteria, and norovirus in the country’s wastewater.
The team from Stanford and U-M, which has been collecting samples since early March, will be analyzing those samples over the next few weeks, hoping to detect the virus and support other COVID-19 tracking efforts.
“The case numbers we’re seeing reported in the US and lots of other places are dependent on how many [diagnostic] test kits we have,” said research lead Krista Wigginton, an associate professor of civil and environmental engineering at U-M and visiting professor at Stanford. “So the curve displaying the number of cases is more of a curve of test kit availability in a community. What we see in wastewater may look totally different.”
Meanwhile, Biobot is currently asking US wastewater treatment facilities for samples for its pro bono testing program. Popular Mechanics said the expected time to results is around three days and the project is still ongoing, having begun sending test kits last week.