The US Centers for Disease Control and Prevention has launched a new program that will help monitor the spread of Covid-19 using sewage.
The new National Wastewater Surveillance System will help local public health leaders better understand the extent of the spread of the pandemic in their communities, the CDC said in an update on its website Monday.
Sewage from house and workplaces can be tested for genetic material from the novel coronavirus. Studies show the virus can be found in feces from people who are sick and also from people who don’t yet have Covid-19 symptoms.
About 80% of the US is on some kind of municipal sewer system, the CDC said. With delays in testing and limited contact tracing, this would be a good complement to those methods and may give a good big picture of how widespread the disease is. Depending on how frequently the wastewater is tested, sewage can be a leading indicator of changes in the burden of the disease in the community, the CDC said.
That would mean the community might have a few extra days to prepare for surge capacity in hospitals or to make lockdown decisions.
Learning from history: This is not the first time the US has used sewage testing to monitor disease. Studies have shown it was an effective method to monitor for disease during polio outbreaks.
This method does have some limitations. It cannot capture information from septic systems. That means it would miss data from more than 60 million people who rely on septic.
In New Hampshire, half of all homes have individual systems. About a third of all new development is also served by septic or some other kind of decentralized system, according to the Environmental Protection Agency.
This method cannot surveil decentralized systems like those used in universities or prisons that treat their waste. Several prisons have been hotspots for Covid-19 infections. It’s also unclear if low levels of infection in a community could be captured this way. The CDC said it is not possible to rely on wastewater data to predict the number of individual infections.
The CDC said it is working on a portal for local leaders to submit their wastewater testing data into a national database and the CDC will release data as it gets it.