Human Waste Could Be The Next Big Weapon in Controlling COVID-19

If you’re a student or a faculty member who spends any time on the University of California, San Diego campus, you may know a lot more about what’s in your pee and poop—and that of your colleagues—than you might care to admit.

Members of the UCSD community can download an app that tells them the COVID-19 status of the wastewater generated in the buildings where they spend the most time. In fact, it offers quite a bit of additional detail too, telling users whether any disease-causing microbes are flourishing in that sewage. If the COVID-19 virus is detected, campus regulars get a notification that they might be either infected or exposed, and they are urged to get tested.

The system has already helped to reduce COVID-19 cases dramatically on campus, from 80-90% of wastewater samples testing positive for the virus between Thanksgiving and January, to only 5% in recent months. The sampling “really gives us an unprecedented ability to track the pandemic day by day as the waves of cases go up and down on campus,” says Rob Knight, professor of pediatrics, computer and engineering and director of the center for microbiome innovation at UCSD.

Not only that, but Knight and his students were also able to use wastewater samples to zero in on people who were likely infected with the virus, but asymptomatic. They placed robots to sample wastewater from individual buildings in sewage pipes before they joined a common effluent, and by last September, they were able to note when samples from a specific building went from negative to positive, and then test everyone frequenting that building to identify the positive case, remove that person from the building, and then keep testing samples to ensure they turned negative again. “Being able to take a whole building, determine which person has COVID-19, remove that person from the building, and see the signal drop back down to zero—that exceeded our wildest dreams,” Knight says. He’s since conducted similarly successfulanalyses of wastewater in San Diego County to predict upcoming surges of COVID-19 infections.

Waste—or more specifically, wastewater—could be the sleeping giant in the universe of disease detection. Because viruses like SARS-CoV-2, which is responsible for COVID-19, are generally shed in human waste, wastewater is proving to be a harbinger of future clusters—if not exactly as pleasant to manage as the proverbial canary in the coal mine, at least a practical warning of cases to come.