CDC and HHS wastewater testing

What’s in it for Purcellville?

By Laura Longley

Last spring, Purcellville became one of the first places in the country which began testing wastewater for coronavirus, after Mayor Kwasi Fraser learned of a new process developed by Boston-based BioBot labs in collaboration with researchers at MIT, Harvard, and Brigham and Women’s Hospital. The Town Council approved the plan and Purcellville’s testing was underway.

What the low-cost test provides is a big picture of how much virus is present in the community overall by measuring the level of the virus’s genetic material—RNA— in human waste.

Think of it as an early warning system for a community. But the alarm has been turned off in Purcellville.

According to Fraser, the testing program was suspended due to Town funding considerations. He expects to look into funding from the federal government’s CARES Act to revive the program. 

Fraser said, “Now that it’s proven that the virus sheds in stool before symptoms are shown, this surveillance can be an early warning indicator for communities across the United States. I encourage citizens to let their elected officials get on board with wastewater-based epidemiology. 

“I saw it as an early warning indicator, absent of the ability and resource to ramp up testing. This wastewater-based epidemiology surveillance provides a window into the health of our community.

“I believe that the more information you have to protect the health of a community like Purcellville, with its 10,000 residents, the greater the likelihood of preventing spikes in COVID-19 cases.”

It has also been Fraser’s vision to leverage the initial Purcellville testing program to obtain federal funding for this and future research efforts following the results of the BioBot program.  

That opportunity for federal support—possibly ongoing—may have just appeared on the horizon. 

On Oct. 23, the Centers for Disease Control and Prevention (CDC) and the U.S. Department of Health and Human Services, announced that they are initiating the National Wastewater Surveillance System (NWSS) in response to the pandemic. As with the data generated by Purcellville’s testing, NWSS intends to help public health officials better understand the extent of COVID-19 infections in communities. According to the announcement, the NWSS will be seeking research and community partners for data collection.

CDC is currently developing a portal for state, tribal, local, and territorial health departments to submit wastewater testing data like that developed by Purcellville for a national database. The database would allow for summarizing and interpreting data for public health action. Participation in a national database would ensure data comparability across jurisdictions.

Wastewater testing data are, of course, not meant to replace existing COVID-19 surveillance systems, but are meant to complement them by providing an efficient pooled community sample, data for communities where timely COVID-19 clinical testing is underutilized or unavailable, and data at the sub-county level.

Under Purcellville’s program, the Town contracted with Inboden Environmental Services of Mt. Jackson, Va., to take two samples a week and ship them to Boston at a cost of $2,540 a month. BioBot labs produced the data.

“There is a series of calculations that they do to actually quantify the amount of cases based upon the amount of flow that the facility had that day,” Mark Inboden told WUSA9

He explained that this technique is called wastewater epidemiology. To do it, his team takes a small sample, which represents the entire town’s sewage for a day. The RNA genetic markers of COVID-19, non-infectious at that point, pass from the body and remain in water flushed down the toilet. 

From Purcellville’s first week of testing, BioBot was able to estimate 50 cases in Purcellville. That estimate spiked to 320 cases a week later, but went down to 65 by the end of the month. 

As the U.S. launches a wastewater testing program, an increasing number of countries around the world are monitoring sewage systems for signs of coronavirus levels. They include Canada, Germany, France, Italy, the Netherlands, Finland, and Hong Kong.