Wastewater samples reveal record levels of coronavirus across U.S.

With at-home Covid-19 tests in high demand and their efficacy in question, health departments from California to Massachusetts are turning to sewage samples to get a better idea of how much the coronavirus is spreading through communities and what might be in store for health care systems.

Experts say wastewater holds the key to better understanding the public health of cities and neighborhoods, especially in underserved areas that do not have equal access to care.

“Every time an infected person uses the toilet, they’re flushing this information down the toilet, where it’s collecting and aggregating and mixing with poop from thousands of other people,” said Newsha Ghaeli, a co-founder and the president of Biobot Analytics, a wastewater epidemiology company based in Massachusetts.

“Even if you can’t access a test, you’re still pooping,” Ghaeli said. “It doesn’t depend on you having access to health care or health insurance.”

Monitoring sewage can also measure other public health concerns, such as obesity, opioids and even polio, said Sheree Pagsuyoin, an associate professor of civil and environmental engineering at the University of Massachusetts Lowell. The pandemic has ushered in a new era of wastewater analysis, once a maligned discipline, to inform public health policy.

“It’s sort of like mapping a trend,” Pagsuyoin said, adding that there has been a “paradigm shift” as more cities turn to sewage analysis to better understand local challenges.

Recent wastewater analysis from a variety of sources across the country indicates an unprecedented surge in infections at a time when millions of people are forced to reconsider travel and holiday plans.

According to Biobot Analytic's wastewater dashboard, coronavirus levels detected in sewage samples across the country are higher now than at any previous point in the pandemic.

Recent wastewater samples in Houston, for example, show that there has been a sharp increase in the amount of the coronavirus detected in the city’s sewage. As of Dec. 20, Houston’s viral load, or the amount of virus found in samples, was at 546 percent compared to July 6, 2020, and the positivity rate was at 14 percent, according to the city Health Department’s wastewater dashboard. The viral load is up from 142 percent last week and 76 percent the previous week. ....