Published by
The Philadelphia Inquirer
The Philadelphia Inquirer
PHILADELPHIA — While COVID-19 cases in Philadelphia are rising to the point that the city will reimpose a mask mandate, a different metric heralded the uptick a few weeks earlier in other parts of the country. The clues were in poop. For months, the city’s public health department has been trying to set up a wastewater surveillance system as an early warning signal for coronavirus outbreaks. As home testing becomes more popular and diagnostic testing less accessible to the uninsured, wastewater numbers are an important supplement to increasingly imperfect testing data. Philadelphia was early o…