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Wastewater testing for COVID-19 could soon be a reality

Isaac Tam and Laila Mufty, environmental inspectors with the City of San José Environmental Services Department, lower an auto-sampler through a manhole at the San José-Santa Clara Regional Wastewater Facility. Photo by City of San José Environmental Services Department
Isaac Tam and Laila Mufty, environmental inspectors with the City of San José Environmental Services Department, lower an auto-sampler through a manhole at the San José-Santa Clara Regional Wastewater Facility. Photo by City of San José Environmental Services Department

Dec. 7 (UPI) -- Researchers and public health officials in the United States could soon be using wastewater surveillance to monitor local rates of COVID-19 transmission.

New research showed settled solid samples collected from sewage treatment facilities hosted higher concentrations of coronavirus viral fragments.

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According to the new analysis, detailed Monday in the journal Environmental Science and Technology, coronavirus RNA was more difficult to detect in liquid samples.

"These results confirmed our early thinking that targeting the solids in wastewater would lead to sensitive and reproducible measurements of COVID-19 in a community," co-senior author Krista Wigginton said in a news release.

"This means that we can track upward trends when cases are still relatively low," said Wigginton, an associate professor in civil and environmental engineering from the University of Michigan.

From the outset of the COVID-19 pandemic, researchers suggested wastewater surveillance for COVID-19 could help officials deploy more targeted interventions and snuff out local outbreaks before they can spread beyond control.

By tracking the levels of viral fragments in local wastewater samples, wastewater monitoring can allow researchers to determine whether infection rates in a given location are trending up or down.

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To utilize wastewater surveillance strategy, scientists need to know how levels of RNA fragments from the virus correspond to levels of COVID-19 infection in local communities.

For the study, researchers collected and analyzed 100 settled solid samples from the San Jose-Santa Clara Regional Wastewater Facility between mid-March and mid-July.

Scientists used statistical models to compare the changing concentrations of genetic material from coronavirus in the waste samples to the shifting numbers of confirmed COVID-19 cases in San Jose-Santa Clara.

Viral fragments in the sewage samples followed the same pattern as confirmed cases, declining in May and June, before peaking in July.

Researchers suggest the monitoring technique could be used to help measure the effectiveness of local mitigation efforts, as well as the impacts of reopening decisions.

However, scientists suggest more work must be done to understand how rates of viral shedding and decay influence detection efforts.

Researchers are currently preparing to roll out a new wastewater surveillance pilot program across eight wastewater treatment plants in California. The program will offer local public health officials real-time data on viral concentrations.

With COVID-19 cases rising rapidly across the state, officials in Southern California recently issued new lockdown restrictions.

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