Lessons learned during COVID-19 are helping health officials keep us safer from other pathogens. Wastewater testing, which became widely used during the pandemic, is becoming more common for things like monkeypox, opioid use, and polio.

Wastewater testing has been around since the early days of polio in the 1940s, but it has never been used on such a wide scale as it has during COVID.

“[COVID] brings the question, what else?” said Dave Larsen, a professor of public health and epidemiology at Syracuse University. “We just finished up a systematic review that there’s a lot of pathogens that can be found in wastewater. Maybe all pathogens at some degree.”

Proteins produced in the body when someone is infected with a pathogen are excreted in stool, so by testing wastewater at various facilities, health officials can get a general idea if a certain virus is circulating in various communities. Experts warn it cannot supplant individual testing, but it can help officials identify communities at risk.

In suburban New York City, the first case of polio in more than a decade was confirmed in late July, but wastewater data suggests it may have been circulating in the area since April.

“Well, if we can just track infectious diseases through wastewater, that’s cheaper, that’s faster, and that increases our emergency preparedness for any emerging pathogen,” said Larsen. “[It allows us to] build a system that is ready for the next coronavirus?”

“Maybe someday we will be looking at sequences in wastewater to inform vaccine design,” added Alexandria Boehm, a professor of environmental engineering at Stanford University. “The wastewater surveillance can help us think about hospital resourcing for different diseases or even directing clinical testing. For example, if we know influenza cases are going up then clinics seeing people with respiratory disease might be more inclined to give an influenza test.”

Data suggests there are 14,000 wastewater sites nationwide that test for things other than pathogens, and just under 1,000 that test for COVID-19.