Union County Health Commissioner Jason Orcena said wastewater monitoring has been a useful tool in tracking COVID-19 trends in Union County. Sewage from the Marysville Wastewater Treatment Plant is tested for fragments of the virus that cause COVID-19. If the amount increases over time, Orcena said it can be indicative of an upcoming surge in cases and hospitalizations. (Graphic submitted)
Monitoring wastewater gives snapshot of community virus growth
Local health officials are analyzing wastewater to help guide their COVID-19 response strategies.
Union County Health Commissioner Jason Orcena said sewage monitoring is a useful “metric to monitor what may be happening” in our community – especially in the midst of a coronavirus surge.
The Marysville Wastewater Treatment Plant has been participating in a statewide initiative, the Ohio Coronavirus Wastewater Monitoring Network, since it was unveiled by Gov. Mike DeWine in early September.
He said he has been “watching every week” since then to follow the trend of virus amounts in Marysville’s sewage.
At the first collection on Sept. 7, there were 30,000 MGC (million gene copies) per day at the Marysville Wastewater Treatment Plant.
Since then, the amount has bobbled at times, but gradually increased to 930,000 MGC per day – the highest it has been – at its most recent collection on Dec. 1.
The treatment plant only collects from City of Marysville homes, so Orcena said it is not a comprehensive analysis but serves as a “good proxy indicator” of COVID trends in the county.
According to the Ohio Department of Health, research has shown that fragments of the virus that causes COVID-19 can be excreted in the feces of symptomatic and asymptomatic infected people.
This viral material can be detected in wastewater as many as three to seven days before an increase in cases or hospitalizations.
Likewise, Orcena said wastewater monitoring is often the first “leading indicator” before an increase in cases, then potential hospitalizations, ICU admissions and deaths.
While it may be an early indicator, the health commissioner emphasized that it is not analyzed singularly.
He said UCHD evaluates the sewage statistics in conjunction with a variety of data points, including those that determine which color Union County is ranked through the Ohio Public Health Advisory System.
Together, he said the measures provide a clearer picture of COVID trends locally.
“It (wastewater monitoring) helps fill in the gaps in information,” he said.
Orcena also noted that the wastewater numbers from one week alone are not particularly useful. Instead, they are viewed over time to see if there is an increasing or decreasing trend.
Currently, he said the trend is “fairly high.”
If the “high, stable trend” continues over the next few weeks, Orcena said it is likely that cases and hospitalizations are will increase as well.
“It would bolster the indication that the surge is still going on,” he said.
While sewage monitoring may alert public health officials of an upcoming trend, Orcena said they are limited logistically as to how quickly they can alter their response.
“There’s not a lot we can adjust in a short period,” he said.
However, he said it gives UCHD notice as to whether they need to reinforce or expand current strategies.
“It tells us: We can’t scale back, can we maintain?” he said.
For instance, Orcena said the current wastewater trend indicates local COVID-19 testing needs to remain at its current capacity. That led UCHD to ask the Ohio National Guard to continue hosting a weekly COVID-19 testing site in Marysville, on top of what the local health department currently offers.
He said UCHD is also maintaining an increased disease investigation staff.
Given the current trends, Orcena said the holiday season will likely be “a difficult period of time.”
In addition to UCHD’s work, he said the health department is encouraging residents and businesses to review the COVID-19 safety protocols, like mask-wearing and social distancing.
He said community members should also consider working from home, if possible.
As the pandemic evolves, Orcena said he hopes other wastewater facilities begin monitoring for COVID and “it becomes a better indicator over time.”