COVID-19: New research examines wastewater to detect community spread

At least 440 people were likely infected with COVID-19 in the area around the treatment facility in Massachusetts — much higher than reported cases

By Rashmi Verma
Published: Thursday 16 April 2020

Scientists and researchers across the world have been vigorously examining ways to curtail the spread of novel coronavirus disease (COVID-19). Surevillance, tracing and detection of community spread continue to be the key to containing the outbreak. This prompted researchers to look at wastewater samples from a treatment plant in Massachusetts for measuring the prevalence of SARS-CoV-2 virus in a given community.

At least 440 people were likely infected with COVID-19 in the area around the treatment facility — much higher than the reported cases — researchers from Biobot Analytics, a biotech startup, along with a team from Massachusetts Institute of Technology (MIT) and Brigham and Women’s Hospital estimated.

The paper was posted on preprint server medRxiv on April 14, 2020.

The researchers collected samples in late March 2020 from the plant serving a large metropolitan area in Massachusetts. They found that the amount of SARS-CoV-2 particles in the sewage samples indicated a far higher number of people likely infected with COVID-19 than the reported cases in that area.

 “It was interesting that our estimation was higher than the number of confirmed cases in the area,” said Mariana Matus, co-founder, Biobot.

She added that public health officials had already considered the possibility that the actual case count was higher than what had been confirmed. The company shared the findings with local health authorities, including the Boston Public Health Commission and the Massachusetts Department of Public Health.

Their response was positive, according to Matus.

“They could believe that [our] numbers could be correct and not out of the realm of possibility,” he added.

In another study published by KWR Water Research Institute, the Netherlands, researchers described detecting the novel coronavirus in sewage samples — sometimes even before public health officials reported the first diagnosed case of COVID-19 in a given community.

The idea to begin testing wastewater for SARS-CoV-2 emerged after recent research revealed that virus particles could be shed through stool and other bodily fluids. The testing begins with collecting sewage samples from local treatment plants and running them through a process that creates millions of copies of viral RNA to study the pathogen in detail.

Another process then looks for specific markers on SARS-CoV-2, to distinguish the virus from other microbes in wastewater samples

Wastewater has been used in other ways as a public health surveillance tool. Biobot, which was spun out of MIT, has also been involved in efforts to detect opioids in wastewater as a way to help communities track patterns of drug use. European countries have long been involved in surveilling the spread of antibiotic resistance through wastewater.

Sewage has been used look at other emerging and known viruses, including polio.

The new research comes at an unprecedented moment in public health: The difficulty and expense of obtaining individual tests for millions of people combined with the virus’ rapid transmission means that public health officials are looking for other ways to grasp the scale of the spread.

Clinical testing is largely for those with more severe symptoms, meaning those who are asymptomatic or have milder symptoms — but can still be contagious — are often missed.

In these instances, wastewater sampling could offer a community-level picture of how the disease has spread. A high concentration of virus particles in a given treatment facility would signal that COVID-19 is still a problem in the surrounding area.

 This could inform public health officials on distancing measures to implement and the precautions healthcare workers ought to take. Experts also say that wastewater detection of SARS-CoV-2 could act not only as a supplement to medical testing, but as an early warning system.


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