With more Americans now testing for COVID-19 at home, it's become more difficult to monitor infection rates. That's why wastewater sampling is more valuable than ever. What we flush down the drain could hold clues to the next surge of COVID-19. "It can be a sort of sentinel for what's coming up next," says Medini Annavajahla, an associate research scientist at Columbia University Medical Center.
The team at the Columbia University Medical Center is studying how wastewater can detect new outbreaks, testing sewage from the hospital, research buildings and nearby college dormitories. Because people with COVID-19 can shed the virus through their waste, the samples reveal infection trends within a community. "Anyone who has contributed to that wastewater is sort of tested at the same time. So, it's like collecting one big pool of samples from a big population," says Annavajahla.
Just by analyzing the wastewater, researchers can even detect what COVID variants are emerging. "As testing of individual people ramps down, as the pandemic sort of comes to a different phase, we don't have the infrastructure anymore to test everyone. So, wastewater is a great cost-effective way to do that at scale."
From California to Wisconsin to Florida, hundreds of communities are using the technique, with full support from the Centers for Disease Control. CDC Director Rochelle Walensky has said, "It's important for communities and health officials to use these measures to help inform prevention strategies for their local area."
More than 400 testing sites across the country are enrolled in a CDC wastewater program that allows states to compare their sewage data.